Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Gene Heskett]

On Friday 29 May 2020 22:36:43 andrew beck wrote:

> actually just another question here gene
>
> so following along that analogy you made with the single bolt for all
> ground wires.  if I connect the pc case to the bolt and also the 0v
> from 24v dc outputs,
>
>  does that mean that I don't have to connect between the mesa 7i76
> field io 0v and logic power 0v?  I think it does.

No, they are to be connected to that same bolt, or in your case to the 
same block. Those cards are NOT grounded by their mounting screws, so in 
order to function, they must also have those "grounds" connected.

If you can measure low ohmage continuity to ground from those terminals 
on the mesa cards when that wire is not connected, then you've a ground 
loop someplace, find it and break that connection. Both the - line from 
the 5 volts, and the -line from the 24 volts connect to this bolt. You 
want this bolt to BE the entire systems common ground point.  This is 
then called a STAR ground.

> just triple checking as things get expensive if I get them wrong and I
> don't want to go down that track

I don't want you to go there either.

One other thing. If you are controlling any relays from the 7i76D's,  
outputs, be sure to add a diode, between the field power +12 or +24 
terminal faced so that any voltage above that +12 or +24, is shunted 
away from the 7i76D output and dumped back into the +12 or +24 supply.

Otherwise the inductive kick which can hit shocking values from the relay 
coil as its being turned off, will blow that 35 volt rated output of the 
7i76D. Probably about the 2nd time your code turns that relay off. :(
The exact same idea applies to any "inductive" load, like a solenoid air 
valve enabling a coolant mister.

Known as a flywheel diode in the parlance of electronics.  It doesn't 
have to be a high powered diode, I keep a bag of 1N914's at $3 for a bag 
of 20 around for that. But test it, I've been known to get duds from 
such sales.

Stay well and safe Andrew.

> regards
>
> Andrew
>
> On Sat, May 30, 2020 at 2:14 PM andrew beck 
>
> wrote:
> > sweet thanks gene
> >
> > I will take your advice and connect the pc chassis to the main
> > ground.
> >
> > I think I will continue to use my grounding blocks for now though as
> > there are about 20 ground cables to connect up and that is getting a
> > bit much for one bolt I think.  hopefully I don't have a problem.  I
> > will let you know if I do haha
> >
> >
> > regards
> >
> > Andrew
> >
> > On Sat, May 30, 2020 at 2:00 PM Gene Heskett  
wrote:
> >> On Friday 29 May 2020 21:22:09 andrew beck wrote:
> >> > thanks guys
> >> >
> >> > just one question about all this gene
> >> >
> >> > why do you suggest breaking the ground off the the computer
> >> > powersupply cable and connecting a ground from the pc chassis to
> >> > the machine main ground?
> >> >
> >> > does the grounding that goes through the cable now good enough?
> >>
> >> The computers 3rd wire should remain if its the ONLY ground
> >> connection in the whole system. But since we power gear thru EMT
> >> tubing, and that also includes a generally better ground, the power
> >> cord to the computer should have that 2nd or 3rd ground removed,
> >> and the computers ground taken back to this common bolt by a direct
> >> from its chassis ground wire, UNLESS the computer is mounted to and
> >> mechanically connected to the frame of the machine and this frame
> >> is grounded to that common bolt.
> >>
> >> Anytime you can lift just one of those wires from that bolt, and
> >> still get ground continuity because its grounded someplace else
> >> too, is bad kharma, find that "other" ground and disconnect it. 
> >> Once, done well, is enough.  A shielded cable where the shield is
> >> grounded at the far end can inject many volts of noise, enough to
> >> blow the interface card. Disconnect that far end. That bolt should
> >> connect to the power wirings "static" ground, and the only
> >> allowable cross connected point to the powerline neutral is in the
> >> main entrance box. You don't care if a nearby lightning strike
> >> might cause that bolt to be 200,000 volts from ground for a
> >> microsecond during that strike, but the +5 volt line will be
> >> 200,005 volts, or 5 volts from what it considers its ground might
> >> be at that exact instant.  You will be damaged ONLY if some other
> >> point in the circuit breaks down and some of that lightning bolts
> >> energy actually flows thru your system to get to that better
> >> ground. Block it with air, the more the merrier.
> >>
> >> > regards
> >> >
> >> > Andrew
> >> >
> >> > On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia
> >> > 
> >> >
> >> > wrote:
> >> > > > Connect all grounds to this bolt, checking that they are not
> >> > > > grounded at the far end.  By doing this, you are establishing
> >> > > > a single point ground that is the zero volt reference for the
> >> > > > whole system. Connect this bolt to the building static
> >> > > > ground, 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

sweet as gene

actually on this currently I have 2 big blocks for grounding.  both
connected together with a decent 6 mm cable.  is that enough to work as one
ground block or do I really need to get and machine/ buy another grounding
block that is all one piece


the latest is the E stop circuit wasn't working.  So I disconnected it and
put a push botton right at the servo on input on the servo drives and that
works to trigger control power on and off to the servos.  so I will go
looking through the rest of the E stop circuit.  there is something on the
estop circuit that didn't like me connecting the  field io power 0v to the
machine frame ground.

regards

Andrew

On Sat, May 30, 2020 at 4:55 PM Gene Heskett  wrote:

> On Friday 29 May 2020 22:14:57 andrew beck wrote:
>
> > sweet thanks gene
> >
> > I will take your advice and connect the pc chassis to the main ground.
> >
> > I think I will continue to use my grounding blocks for now though as
> > there are about 20 ground cables to connect up and that is getting a
> > bit much for one bolt I think.  hopefully I don't have a problem.  I
> > will let you know if I do haha
> >
> Use only one block, and put them as close together as you can.
> >
> > regards
> >
> > Andrew
> >
> > On Sat, May 30, 2020 at 2:00 PM Gene Heskett 
> wrote:
> > > On Friday 29 May 2020 21:22:09 andrew beck wrote:
> > > > thanks guys
> > > >
> > > > just one question about all this gene
> > > >
> > > > why do you suggest breaking the ground off the the computer
> > > > powersupply cable and connecting a ground from the pc chassis to
> > > > the machine main ground?
> > > >
> > > > does the grounding that goes through the cable now good enough?
> > >
> > > The computers 3rd wire should remain if its the ONLY ground
> > > connection in the whole system. But since we power gear thru EMT
> > > tubing, and that also includes a generally better ground, the power
> > > cord to the computer should have that 2nd or 3rd ground removed, and
> > > the computers ground taken back to this common bolt by a direct from
> > > its chassis ground wire, UNLESS the computer is mounted to and
> > > mechanically connected to the frame of the machine and this frame is
> > > grounded to that common bolt.
> > >
> > > Anytime you can lift just one of those wires from that bolt, and
> > > still get ground continuity because its grounded someplace else too,
> > > is bad kharma, find that "other" ground and disconnect it.  Once,
> > > done well, is enough.  A shielded cable where the shield is grounded
> > > at the far end can inject many volts of noise, enough to blow the
> > > interface card. Disconnect that far end. That bolt should connect to
> > > the power wirings "static" ground, and the only allowable cross
> > > connected point to the powerline neutral is in the main entrance
> > > box. You don't care if a nearby lightning strike might cause that
> > > bolt to be 200,000 volts from ground for a microsecond during that
> > > strike, but the +5 volt line will be 200,005 volts, or 5 volts from
> > > what it considers its ground might be at that exact instant.  You
> > > will be damaged ONLY if some other point in the circuit breaks down
> > > and some of that lightning bolts energy actually flows thru your
> > > system to get to that better ground. Block it with air, the more the
> > > merrier.
> > >
> > > > regards
> > > >
> > > > Andrew
> > > >
> > > > On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia
> > > > 
> > > >
> > > > wrote:
> > > > > > Connect all grounds to this bolt, checking that they are not
> > > > > > grounded at the far end.  By doing this, you are establishing
> > > > > > a single point ground that is the zero volt reference for the
> > > > > > whole system. Connect this bolt to the building static ground,
> > > > > > the bare wire in most power cabling.
> > > > > >
> > > > > > Connect the machines frame to this bolt.
> > > > > >
> > > > > > Connect the - rails of all supplies to this bolt.
> > > > > >
> > > > > > Connect the - terminals of all cards to this bolt.
> > > > > >
> > > > > > Break the 3rd pin off the computers supply cable and connect
> > > > > > the computers chassis to this bolt. Power the computer not
> > > > > > from the wall, but from the same power feeding this box.
> > > > > >
> > > > > > Connect the shielding of all shielded cabling to this bolt. Do
> > > > > > not connect the far end of this shielding to anything that is
> > > > > > otherwise grounded.
> > > > > >
> > > > > > By making sure these grounds are not connected anyplace else
> > > > > > you are breaking any ground loops which can and will act as
> > > > > > antennas to insert noise into your control signals.
> > > > > >
> > > > > > By having this single point ground, a nearby lightning strike
> > > > > > can inject a 100k volt pulse into the system ground as what
> > > > > > would be called a "ground bounce",  but the system will not
> > > > > > see it as noise nor be damaged, because everything is 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Gene Heskett]

On Friday 29 May 2020 22:14:57 andrew beck wrote:

> sweet thanks gene
>
> I will take your advice and connect the pc chassis to the main ground.
>
> I think I will continue to use my grounding blocks for now though as
> there are about 20 ground cables to connect up and that is getting a
> bit much for one bolt I think.  hopefully I don't have a problem.  I
> will let you know if I do haha
>
Use only one block, and put them as close together as you can.
>
> regards
>
> Andrew
>
> On Sat, May 30, 2020 at 2:00 PM Gene Heskett  
wrote:
> > On Friday 29 May 2020 21:22:09 andrew beck wrote:
> > > thanks guys
> > >
> > > just one question about all this gene
> > >
> > > why do you suggest breaking the ground off the the computer
> > > powersupply cable and connecting a ground from the pc chassis to
> > > the machine main ground?
> > >
> > > does the grounding that goes through the cable now good enough?
> >
> > The computers 3rd wire should remain if its the ONLY ground
> > connection in the whole system. But since we power gear thru EMT
> > tubing, and that also includes a generally better ground, the power
> > cord to the computer should have that 2nd or 3rd ground removed, and
> > the computers ground taken back to this common bolt by a direct from
> > its chassis ground wire, UNLESS the computer is mounted to and
> > mechanically connected to the frame of the machine and this frame is
> > grounded to that common bolt.
> >
> > Anytime you can lift just one of those wires from that bolt, and
> > still get ground continuity because its grounded someplace else too,
> > is bad kharma, find that "other" ground and disconnect it.  Once,
> > done well, is enough.  A shielded cable where the shield is grounded
> > at the far end can inject many volts of noise, enough to blow the
> > interface card. Disconnect that far end. That bolt should connect to
> > the power wirings "static" ground, and the only allowable cross
> > connected point to the powerline neutral is in the main entrance
> > box. You don't care if a nearby lightning strike might cause that
> > bolt to be 200,000 volts from ground for a microsecond during that
> > strike, but the +5 volt line will be 200,005 volts, or 5 volts from
> > what it considers its ground might be at that exact instant.  You
> > will be damaged ONLY if some other point in the circuit breaks down
> > and some of that lightning bolts energy actually flows thru your
> > system to get to that better ground. Block it with air, the more the
> > merrier.
> >
> > > regards
> > >
> > > Andrew
> > >
> > > On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia
> > > 
> > >
> > > wrote:
> > > > > Connect all grounds to this bolt, checking that they are not
> > > > > grounded at the far end.  By doing this, you are establishing
> > > > > a single point ground that is the zero volt reference for the
> > > > > whole system. Connect this bolt to the building static ground,
> > > > > the bare wire in most power cabling.
> > > > >
> > > > > Connect the machines frame to this bolt.
> > > > >
> > > > > Connect the - rails of all supplies to this bolt.
> > > > >
> > > > > Connect the - terminals of all cards to this bolt.
> > > > >
> > > > > Break the 3rd pin off the computers supply cable and connect
> > > > > the computers chassis to this bolt. Power the computer not
> > > > > from the wall, but from the same power feeding this box.
> > > > >
> > > > > Connect the shielding of all shielded cabling to this bolt. Do
> > > > > not connect the far end of this shielding to anything that is
> > > > > otherwise grounded.
> > > > >
> > > > > By making sure these grounds are not connected anyplace else
> > > > > you are breaking any ground loops which can and will act as
> > > > > antennas to insert noise into your control signals.
> > > > >
> > > > > By having this single point ground, a nearby lightning strike
> > > > > can inject a 100k volt pulse into the system ground as what
> > > > > would be called a "ground bounce",  but the system will not
> > > > > see it as noise nor be damaged, because everything is bouncing
> > > > > in unison.
> > > > >
> > > > > Regardless of what that bolt does during the strike, the 5
> > > > > volt supply remains at 5 volts to this bolt, and the 24 volt
> > > > > supply remains at 24 volts to this bolt.
> > > > >
> > > > > And when the storm is done, your chances of having anything
> > > > > damaged is reduced to the vanishing point.
> > > >
> > > > Thanks for this Gene. It's more than useful to remember how to
> > > > properly ground logic circuits to avoid external noise and
> > > > dangerous voltage spikes.
> > > >
> > > > El jue., 28 may. 2020 a las 20:35, Gene Heskett
> > > > ()
> > > >
> > > > escribió:
> > > > > On Thursday 28 May 2020 18:36:10 andrew beck wrote:
> > > > > > hey gene
> > > > > >
> > > > > > sorry for the slow reply
> > > > > >
> > > > > > just getting to this grounding thing now.
> > > > > >
> > > > > > currently I have single large copper block 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

ok just a update here.

I connected the field IO 0v to machine ground
I connected the computer chassis to machine ground

I didn't know that I had to test for resistance between machine ground and
dc 0v with the machine turned off.  so powered it straight up..

anyway just waiting for 10 mins now for the power to all seep out so I can
go back and measure resistance

while it was live I took some readings though.  there is very low
resistance (0.00ohms) between field IO power 0v and machine ground.

the between the computer chassis and machine ground block there is very low
resistance

but between the 7i76 logic power and machine ground block there is about 70
ohms while the machine is powered up.

getting a bit lost here but will post back once I measure the machine when
the power is all off.

regards

Andrew

On Sat, May 30, 2020 at 2:36 PM andrew beck 
wrote:

> actually just another question here gene
>
> so following along that analogy you made with the single bolt for all
> ground wires.  if I connect the pc case to the bolt and also the 0v from
> 24v dc outputs,
>
>  does that mean that I don't have to connect between the mesa 7i76 field
> io 0v and logic power 0v?  I think it does.
> just triple checking as things get expensive if I get them wrong and I
> don't want to go down that track
>
> regards
>
> Andrew
>
> On Sat, May 30, 2020 at 2:14 PM andrew beck 
> wrote:
>
>> sweet thanks gene
>>
>> I will take your advice and connect the pc chassis to the main ground.
>>
>> I think I will continue to use my grounding blocks for now though as
>> there are about 20 ground cables to connect up and that is getting a bit
>> much for one bolt I think.  hopefully I don't have a problem.  I will let
>> you know if I do haha
>>
>>
>> regards
>>
>> Andrew
>>
>>
>> On Sat, May 30, 2020 at 2:00 PM Gene Heskett 
>> wrote:
>>
>>> On Friday 29 May 2020 21:22:09 andrew beck wrote:
>>>
>>> > thanks guys
>>> >
>>> > just one question about all this gene
>>> >
>>> > why do you suggest breaking the ground off the the computer
>>> > powersupply cable and connecting a ground from the pc chassis to the
>>> > machine main ground?
>>> >
>>> > does the grounding that goes through the cable now good enough?
>>> The computers 3rd wire should remain if its the ONLY ground connection
>>> in
>>> the whole system. But since we power gear thru EMT tubing, and that also
>>> includes a generally better ground, the power cord to the computer
>>> should have that 2nd or 3rd ground removed, and the computers ground
>>> taken back to this common bolt by a direct from its chassis ground wire,
>>> UNLESS the computer is mounted to and mechanically connected to the
>>> frame of the machine and this frame is grounded to that common bolt.
>>>
>>> Anytime you can lift just one of those wires from that bolt, and still
>>> get ground continuity because its grounded someplace else too, is bad
>>> kharma, find that "other" ground and disconnect it.  Once, done well, is
>>> enough.  A shielded cable where the shield is grounded at the far end
>>> can inject many volts of noise, enough to blow the interface card.
>>> Disconnect that far end. That bolt should connect to the power
>>> wirings "static" ground, and the only allowable cross connected point to
>>> the powerline neutral is in the main entrance box. You don't care if a
>>> nearby lightning strike might cause that bolt to be 200,000 volts from
>>> ground for a microsecond during that strike, but the +5 volt line will
>>> be 200,005 volts, or 5 volts from what it considers its ground might be
>>> at that exact instant.  You will be damaged ONLY if some other point in
>>> the circuit breaks down and some of that lightning bolts energy actually
>>> flows thru your system to get to that better ground. Block it with air,
>>> the more the merrier.
>>>
>>> > regards
>>> >
>>> > Andrew
>>> >
>>> > On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia
>>> > 
>>> >
>>> > wrote:
>>> > > > Connect all grounds to this bolt, checking that they are not
>>> > > > grounded at the far end.  By doing this, you are establishing a
>>> > > > single point ground that is the zero volt reference for the whole
>>> > > > system. Connect this bolt to the building static ground, the bare
>>> > > > wire in most power cabling.
>>> > > >
>>> > > > Connect the machines frame to this bolt.
>>> > > >
>>> > > > Connect the - rails of all supplies to this bolt.
>>> > > >
>>> > > > Connect the - terminals of all cards to this bolt.
>>> > > >
>>> > > > Break the 3rd pin off the computers supply cable and connect the
>>> > > > computers chassis to this bolt. Power the computer not from the
>>> > > > wall, but from the same power feeding this box.
>>> > > >
>>> > > > Connect the shielding of all shielded cabling to this bolt. Do not
>>> > > > connect the far end of this shielding to anything that is
>>> > > > otherwise grounded.
>>> > > >
>>> > > > By making sure these grounds are not connected anyplace else you
>>> > > > are breaking 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

actually just another question here gene

so following along that analogy you made with the single bolt for all
ground wires.  if I connect the pc case to the bolt and also the 0v from
24v dc outputs,

 does that mean that I don't have to connect between the mesa 7i76 field io
0v and logic power 0v?  I think it does.
just triple checking as things get expensive if I get them wrong and I
don't want to go down that track

regards

Andrew

On Sat, May 30, 2020 at 2:14 PM andrew beck 
wrote:

> sweet thanks gene
>
> I will take your advice and connect the pc chassis to the main ground.
>
> I think I will continue to use my grounding blocks for now though as there
> are about 20 ground cables to connect up and that is getting a bit much for
> one bolt I think.  hopefully I don't have a problem.  I will let you know
> if I do haha
>
>
> regards
>
> Andrew
>
>
> On Sat, May 30, 2020 at 2:00 PM Gene Heskett  wrote:
>
>> On Friday 29 May 2020 21:22:09 andrew beck wrote:
>>
>> > thanks guys
>> >
>> > just one question about all this gene
>> >
>> > why do you suggest breaking the ground off the the computer
>> > powersupply cable and connecting a ground from the pc chassis to the
>> > machine main ground?
>> >
>> > does the grounding that goes through the cable now good enough?
>> The computers 3rd wire should remain if its the ONLY ground connection in
>> the whole system. But since we power gear thru EMT tubing, and that also
>> includes a generally better ground, the power cord to the computer
>> should have that 2nd or 3rd ground removed, and the computers ground
>> taken back to this common bolt by a direct from its chassis ground wire,
>> UNLESS the computer is mounted to and mechanically connected to the
>> frame of the machine and this frame is grounded to that common bolt.
>>
>> Anytime you can lift just one of those wires from that bolt, and still
>> get ground continuity because its grounded someplace else too, is bad
>> kharma, find that "other" ground and disconnect it.  Once, done well, is
>> enough.  A shielded cable where the shield is grounded at the far end
>> can inject many volts of noise, enough to blow the interface card.
>> Disconnect that far end. That bolt should connect to the power
>> wirings "static" ground, and the only allowable cross connected point to
>> the powerline neutral is in the main entrance box. You don't care if a
>> nearby lightning strike might cause that bolt to be 200,000 volts from
>> ground for a microsecond during that strike, but the +5 volt line will
>> be 200,005 volts, or 5 volts from what it considers its ground might be
>> at that exact instant.  You will be damaged ONLY if some other point in
>> the circuit breaks down and some of that lightning bolts energy actually
>> flows thru your system to get to that better ground. Block it with air,
>> the more the merrier.
>>
>> > regards
>> >
>> > Andrew
>> >
>> > On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia
>> > 
>> >
>> > wrote:
>> > > > Connect all grounds to this bolt, checking that they are not
>> > > > grounded at the far end.  By doing this, you are establishing a
>> > > > single point ground that is the zero volt reference for the whole
>> > > > system. Connect this bolt to the building static ground, the bare
>> > > > wire in most power cabling.
>> > > >
>> > > > Connect the machines frame to this bolt.
>> > > >
>> > > > Connect the - rails of all supplies to this bolt.
>> > > >
>> > > > Connect the - terminals of all cards to this bolt.
>> > > >
>> > > > Break the 3rd pin off the computers supply cable and connect the
>> > > > computers chassis to this bolt. Power the computer not from the
>> > > > wall, but from the same power feeding this box.
>> > > >
>> > > > Connect the shielding of all shielded cabling to this bolt. Do not
>> > > > connect the far end of this shielding to anything that is
>> > > > otherwise grounded.
>> > > >
>> > > > By making sure these grounds are not connected anyplace else you
>> > > > are breaking any ground loops which can and will act as antennas
>> > > > to insert noise into your control signals.
>> > > >
>> > > > By having this single point ground, a nearby lightning strike can
>> > > > inject a 100k volt pulse into the system ground as what would be
>> > > > called a "ground bounce",  but the system will not see it as noise
>> > > > nor be damaged, because everything is bouncing in unison.
>> > > >
>> > > > Regardless of what that bolt does during the strike, the 5 volt
>> > > > supply remains at 5 volts to this bolt, and the 24 volt supply
>> > > > remains at 24 volts to this bolt.
>> > > >
>> > > > And when the storm is done, your chances of having anything
>> > > > damaged is reduced to the vanishing point.
>> > >
>> > > Thanks for this Gene. It's more than useful to remember how to
>> > > properly ground logic circuits to avoid external noise and dangerous
>> > > voltage spikes.
>> > >
>> > > El jue., 28 may. 2020 a las 20:35, Gene Heskett
>> > > ()
>> > >
>> > > 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

sweet thanks gene

I will take your advice and connect the pc chassis to the main ground.

I think I will continue to use my grounding blocks for now though as there
are about 20 ground cables to connect up and that is getting a bit much for
one bolt I think.  hopefully I don't have a problem.  I will let you know
if I do haha


regards

Andrew


On Sat, May 30, 2020 at 2:00 PM Gene Heskett  wrote:

> On Friday 29 May 2020 21:22:09 andrew beck wrote:
>
> > thanks guys
> >
> > just one question about all this gene
> >
> > why do you suggest breaking the ground off the the computer
> > powersupply cable and connecting a ground from the pc chassis to the
> > machine main ground?
> >
> > does the grounding that goes through the cable now good enough?
> The computers 3rd wire should remain if its the ONLY ground connection in
> the whole system. But since we power gear thru EMT tubing, and that also
> includes a generally better ground, the power cord to the computer
> should have that 2nd or 3rd ground removed, and the computers ground
> taken back to this common bolt by a direct from its chassis ground wire,
> UNLESS the computer is mounted to and mechanically connected to the
> frame of the machine and this frame is grounded to that common bolt.
>
> Anytime you can lift just one of those wires from that bolt, and still
> get ground continuity because its grounded someplace else too, is bad
> kharma, find that "other" ground and disconnect it.  Once, done well, is
> enough.  A shielded cable where the shield is grounded at the far end
> can inject many volts of noise, enough to blow the interface card.
> Disconnect that far end. That bolt should connect to the power
> wirings "static" ground, and the only allowable cross connected point to
> the powerline neutral is in the main entrance box. You don't care if a
> nearby lightning strike might cause that bolt to be 200,000 volts from
> ground for a microsecond during that strike, but the +5 volt line will
> be 200,005 volts, or 5 volts from what it considers its ground might be
> at that exact instant.  You will be damaged ONLY if some other point in
> the circuit breaks down and some of that lightning bolts energy actually
> flows thru your system to get to that better ground. Block it with air,
> the more the merrier.
>
> > regards
> >
> > Andrew
> >
> > On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia
> > 
> >
> > wrote:
> > > > Connect all grounds to this bolt, checking that they are not
> > > > grounded at the far end.  By doing this, you are establishing a
> > > > single point ground that is the zero volt reference for the whole
> > > > system. Connect this bolt to the building static ground, the bare
> > > > wire in most power cabling.
> > > >
> > > > Connect the machines frame to this bolt.
> > > >
> > > > Connect the - rails of all supplies to this bolt.
> > > >
> > > > Connect the - terminals of all cards to this bolt.
> > > >
> > > > Break the 3rd pin off the computers supply cable and connect the
> > > > computers chassis to this bolt. Power the computer not from the
> > > > wall, but from the same power feeding this box.
> > > >
> > > > Connect the shielding of all shielded cabling to this bolt. Do not
> > > > connect the far end of this shielding to anything that is
> > > > otherwise grounded.
> > > >
> > > > By making sure these grounds are not connected anyplace else you
> > > > are breaking any ground loops which can and will act as antennas
> > > > to insert noise into your control signals.
> > > >
> > > > By having this single point ground, a nearby lightning strike can
> > > > inject a 100k volt pulse into the system ground as what would be
> > > > called a "ground bounce",  but the system will not see it as noise
> > > > nor be damaged, because everything is bouncing in unison.
> > > >
> > > > Regardless of what that bolt does during the strike, the 5 volt
> > > > supply remains at 5 volts to this bolt, and the 24 volt supply
> > > > remains at 24 volts to this bolt.
> > > >
> > > > And when the storm is done, your chances of having anything
> > > > damaged is reduced to the vanishing point.
> > >
> > > Thanks for this Gene. It's more than useful to remember how to
> > > properly ground logic circuits to avoid external noise and dangerous
> > > voltage spikes.
> > >
> > > El jue., 28 may. 2020 a las 20:35, Gene Heskett
> > > ()
> > >
> > > escribió:
> > > > On Thursday 28 May 2020 18:36:10 andrew beck wrote:
> > > > > hey gene
> > > > >
> > > > > sorry for the slow reply
> > > > >
> > > > > just getting to this grounding thing now.
> > > > >
> > > > > currently I have single large copper block with a lot of holes
> > > > > in it for terminals, this is connected to the earth(ground) wire
> > > > > that goes back to the whole shed main ground wire rod in the
> > > > > dirt
> > > > >
> > > > > all my servo drives and vfd main grounds go back to this point
> > > > > as do all motor grounds etc.  this is how heidenhain set up the
> > > > > 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Gene Heskett]

On Friday 29 May 2020 21:22:09 andrew beck wrote:

> thanks guys
>
> just one question about all this gene
>
> why do you suggest breaking the ground off the the computer
> powersupply cable and connecting a ground from the pc chassis to the
> machine main ground?
>
> does the grounding that goes through the cable now good enough?
The computers 3rd wire should remain if its the ONLY ground connection in 
the whole system. But since we power gear thru EMT tubing, and that also 
includes a generally better ground, the power cord to the computer 
should have that 2nd or 3rd ground removed, and the computers ground 
taken back to this common bolt by a direct from its chassis ground wire, 
UNLESS the computer is mounted to and mechanically connected to the 
frame of the machine and this frame is grounded to that common bolt.

Anytime you can lift just one of those wires from that bolt, and still 
get ground continuity because its grounded someplace else too, is bad 
kharma, find that "other" ground and disconnect it.  Once, done well, is 
enough.  A shielded cable where the shield is grounded at the far end 
can inject many volts of noise, enough to blow the interface card. 
Disconnect that far end. That bolt should connect to the power 
wirings "static" ground, and the only allowable cross connected point to 
the powerline neutral is in the main entrance box. You don't care if a 
nearby lightning strike might cause that bolt to be 200,000 volts from 
ground for a microsecond during that strike, but the +5 volt line will 
be 200,005 volts, or 5 volts from what it considers its ground might be 
at that exact instant.  You will be damaged ONLY if some other point in 
the circuit breaks down and some of that lightning bolts energy actually 
flows thru your system to get to that better ground. Block it with air, 
the more the merrier.
 
> regards
>
> Andrew
>
> On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia
> 
>
> wrote:
> > > Connect all grounds to this bolt, checking that they are not
> > > grounded at the far end.  By doing this, you are establishing a
> > > single point ground that is the zero volt reference for the whole
> > > system. Connect this bolt to the building static ground, the bare
> > > wire in most power cabling.
> > >
> > > Connect the machines frame to this bolt.
> > >
> > > Connect the - rails of all supplies to this bolt.
> > >
> > > Connect the - terminals of all cards to this bolt.
> > >
> > > Break the 3rd pin off the computers supply cable and connect the
> > > computers chassis to this bolt. Power the computer not from the
> > > wall, but from the same power feeding this box.
> > >
> > > Connect the shielding of all shielded cabling to this bolt. Do not
> > > connect the far end of this shielding to anything that is
> > > otherwise grounded.
> > >
> > > By making sure these grounds are not connected anyplace else you
> > > are breaking any ground loops which can and will act as antennas
> > > to insert noise into your control signals.
> > >
> > > By having this single point ground, a nearby lightning strike can
> > > inject a 100k volt pulse into the system ground as what would be
> > > called a "ground bounce",  but the system will not see it as noise
> > > nor be damaged, because everything is bouncing in unison.
> > >
> > > Regardless of what that bolt does during the strike, the 5 volt
> > > supply remains at 5 volts to this bolt, and the 24 volt supply
> > > remains at 24 volts to this bolt.
> > >
> > > And when the storm is done, your chances of having anything
> > > damaged is reduced to the vanishing point.
> >
> > Thanks for this Gene. It's more than useful to remember how to
> > properly ground logic circuits to avoid external noise and dangerous
> > voltage spikes.
> >
> > El jue., 28 may. 2020 a las 20:35, Gene Heskett
> > ()
> >
> > escribió:
> > > On Thursday 28 May 2020 18:36:10 andrew beck wrote:
> > > > hey gene
> > > >
> > > > sorry for the slow reply
> > > >
> > > > just getting to this grounding thing now.
> > > >
> > > > currently I have single large copper block with a lot of holes
> > > > in it for terminals, this is connected to the earth(ground) wire
> > > > that goes back to the whole shed main ground wire rod in the
> > > > dirt
> > > >
> > > > all my servo drives and vfd main grounds go back to this point
> > > > as do all motor grounds etc.  this is how heidenhain set up the
> > > > machine originally and they have a whole grounding schematic
> > > > showing how it all works.  I have basically copied that.
> > > >
> > > > I have 2 meanwell 24v powersupplies that have the ground wire on
> > > > the input side also connected to ground.  the output side (phase
> > > > and neutral) are floating relative to ground and not connected
> > > > to ground at all I think.  as the meanwell switching powersupply
> > > > output should be isolated from the input.  I think this is
> > > > correct
> > > >
> > > > the computer cord ground wire is currently connected to this

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

thanks guys

just one question about all this gene

why do you suggest breaking the ground off the the computer powersupply
cable and connecting a ground from the pc chassis to the machine main
ground?

does the grounding that goes through the cable now good enough?

regards

Andrew

On Fri, May 29, 2020 at 11:53 AM Leonardo Marsaglia 
wrote:

> >
> > Connect all grounds to this bolt, checking that they are not grounded at
> > the far end.  By doing this, you are establishing a single point ground
> > that is the zero volt reference for the whole system. Connect this bolt
> > to the building static ground, the bare wire in most power cabling.
> >
> > Connect the machines frame to this bolt.
> >
> > Connect the - rails of all supplies to this bolt.
> >
> > Connect the - terminals of all cards to this bolt.
> >
> > Break the 3rd pin off the computers supply cable and connect the
> > computers chassis to this bolt. Power the computer not from the wall,
> > but from the same power feeding this box.
> >
> > Connect the shielding of all shielded cabling to this bolt. Do not
> > connect the far end of this shielding to anything that is otherwise
> > grounded.
> >
> > By making sure these grounds are not connected anyplace else you are
> > breaking any ground loops which can and will act as antennas to insert
> > noise into your control signals.
> >
> > By having this single point ground, a nearby lightning strike can inject
> > a 100k volt pulse into the system ground as what would be called
> > a "ground bounce",  but the system will not see it as noise nor be
> > damaged, because everything is bouncing in unison.
> >
> > Regardless of what that bolt does during the strike, the 5 volt supply
> > remains at 5 volts to this bolt, and the 24 volt supply remains at 24
> > volts to this bolt.
> >
> > And when the storm is done, your chances of having anything damaged is
> > reduced to the vanishing point.
>
>
> Thanks for this Gene. It's more than useful to remember how to properly
> ground logic circuits to avoid external noise and dangerous voltage spikes.
>
> El jue., 28 may. 2020 a las 20:35, Gene Heskett ()
> escribió:
>
> > On Thursday 28 May 2020 18:36:10 andrew beck wrote:
> >
> > > hey gene
> > >
> > > sorry for the slow reply
> > >
> > > just getting to this grounding thing now.
> > >
> > > currently I have single large copper block with a lot of holes in it
> > > for terminals, this is connected to the earth(ground) wire that goes
> > > back to the whole shed main ground wire rod in the dirt
> > >
> > > all my servo drives and vfd main grounds go back to this point as do
> > > all motor grounds etc.  this is how heidenhain set up the machine
> > > originally and they have a whole grounding schematic showing how it
> > > all works.  I have basically copied that.
> > >
> > > I have 2 meanwell 24v powersupplies that have the ground wire on the
> > > input side also connected to ground.  the output side (phase and
> > > neutral) are floating relative to ground and not connected to ground
> > > at all I think.  as the meanwell switching powersupply output should
> > > be isolated from the input.  I think this is correct
> > >
> > > the computer cord ground wire is currently connected to this same
> > > large copper block.
> > >
> > The sheer bulk of that copper bother me a bit because it can function as
> > an antenna.  A single bolt, tightened well into the chassis with all the
> > connections stacked up on this bolt will be quieter.
> >
> > > my computer via the 5i25 currently supplies 5v logic power to the 7i76
> > Thats fine, but if using a std bob on the other 5i25 port, do NOT enable
> > the jumper for that port as the bobs std grounding will short circuit
> > that, you must supply a separated 5 volts to that bob, or plug in a usb
> > cable to steal it from the pc's usb circuitry,
> > >
> > > and one of the 24v meanwell powersupplys supplies the 24v field io for
> > > the 7i76
> > I have all supplies - outputs tied to ground.  It might work 99% of the
> > time without it, till the first nearby lightning strike...  With all
> > that grounded, it will probably keep right on working after the strike.
> >
> > > my encoder problems started when I connected up the servo drive
> > > simulated encoder output to the 7i76 encoder counter.  I haven't
> > > connected the 5v and 24 v grounds together.  they did work for awhile
> > > but don't now
> >
> > Tie the -'s to the ground bolt. Then do a full powerdown on the whole
> > thing, with about a 10 count in the dark, then boot everything back up
> > and test it.  And report what you get now...
> >
> > > I have a 7i89 and 7i84 coming soon and will need a external 5v
> > > powersupply anyway i think so will change when they arrive here from
> > > america.
> > >
> > > anyway I read your reply and got a bit confused could you read my
> > > email here and let me know what I need to change and why I should do
> > > it this way just so I understand.
> >
> > Basicly, your 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Leonardo Marsaglia]

>
> Connect all grounds to this bolt, checking that they are not grounded at
> the far end.  By doing this, you are establishing a single point ground
> that is the zero volt reference for the whole system. Connect this bolt
> to the building static ground, the bare wire in most power cabling.
>
> Connect the machines frame to this bolt.
>
> Connect the - rails of all supplies to this bolt.
>
> Connect the - terminals of all cards to this bolt.
>
> Break the 3rd pin off the computers supply cable and connect the
> computers chassis to this bolt. Power the computer not from the wall,
> but from the same power feeding this box.
>
> Connect the shielding of all shielded cabling to this bolt. Do not
> connect the far end of this shielding to anything that is otherwise
> grounded.
>
> By making sure these grounds are not connected anyplace else you are
> breaking any ground loops which can and will act as antennas to insert
> noise into your control signals.
>
> By having this single point ground, a nearby lightning strike can inject
> a 100k volt pulse into the system ground as what would be called
> a "ground bounce",  but the system will not see it as noise nor be
> damaged, because everything is bouncing in unison.
>
> Regardless of what that bolt does during the strike, the 5 volt supply
> remains at 5 volts to this bolt, and the 24 volt supply remains at 24
> volts to this bolt.
>
> And when the storm is done, your chances of having anything damaged is
> reduced to the vanishing point.


Thanks for this Gene. It's more than useful to remember how to properly
ground logic circuits to avoid external noise and dangerous voltage spikes.

El jue., 28 may. 2020 a las 20:35, Gene Heskett ()
escribió:

> On Thursday 28 May 2020 18:36:10 andrew beck wrote:
>
> > hey gene
> >
> > sorry for the slow reply
> >
> > just getting to this grounding thing now.
> >
> > currently I have single large copper block with a lot of holes in it
> > for terminals, this is connected to the earth(ground) wire that goes
> > back to the whole shed main ground wire rod in the dirt
> >
> > all my servo drives and vfd main grounds go back to this point as do
> > all motor grounds etc.  this is how heidenhain set up the machine
> > originally and they have a whole grounding schematic showing how it
> > all works.  I have basically copied that.
> >
> > I have 2 meanwell 24v powersupplies that have the ground wire on the
> > input side also connected to ground.  the output side (phase and
> > neutral) are floating relative to ground and not connected to ground
> > at all I think.  as the meanwell switching powersupply output should
> > be isolated from the input.  I think this is correct
> >
> > the computer cord ground wire is currently connected to this same
> > large copper block.
> >
> The sheer bulk of that copper bother me a bit because it can function as
> an antenna.  A single bolt, tightened well into the chassis with all the
> connections stacked up on this bolt will be quieter.
>
> > my computer via the 5i25 currently supplies 5v logic power to the 7i76
> Thats fine, but if using a std bob on the other 5i25 port, do NOT enable
> the jumper for that port as the bobs std grounding will short circuit
> that, you must supply a separated 5 volts to that bob, or plug in a usb
> cable to steal it from the pc's usb circuitry,
> >
> > and one of the 24v meanwell powersupplys supplies the 24v field io for
> > the 7i76
> I have all supplies - outputs tied to ground.  It might work 99% of the
> time without it, till the first nearby lightning strike...  With all
> that grounded, it will probably keep right on working after the strike.
>
> > my encoder problems started when I connected up the servo drive
> > simulated encoder output to the 7i76 encoder counter.  I haven't
> > connected the 5v and 24 v grounds together.  they did work for awhile
> > but don't now
>
> Tie the -'s to the ground bolt. Then do a full powerdown on the whole
> thing, with about a 10 count in the dark, then boot everything back up
> and test it.  And report what you get now...
>
> > I have a 7i89 and 7i84 coming soon and will need a external 5v
> > powersupply anyway i think so will change when they arrive here from
> > america.
> >
> > anyway I read your reply and got a bit confused could you read my
> > email here and let me know what I need to change and why I should do
> > it this way just so I understand.
>
> Basicly, your lack of a common ground has possibly allowed voltages well
> above the breakdown voltages of the chips on these cards, between the -
> connections and a real ground. They all have what can look like an SCR
> as an isolation tub under each transistor its built from, and these
> SCR's can upset the whole thing if they get turned on.  Thats why the
> count to 10 or more powerdown is done, giving these SCR's time enough at
> a low enough voltage to turn them off, at which point the circuit looks
> more normal and may even work. If not, then 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Gene Heskett]

On Thursday 28 May 2020 18:36:10 andrew beck wrote:

> hey gene
>
> sorry for the slow reply
>
> just getting to this grounding thing now.
>
> currently I have single large copper block with a lot of holes in it
> for terminals, this is connected to the earth(ground) wire that goes
> back to the whole shed main ground wire rod in the dirt
>
> all my servo drives and vfd main grounds go back to this point as do
> all motor grounds etc.  this is how heidenhain set up the machine
> originally and they have a whole grounding schematic showing how it
> all works.  I have basically copied that.
>
> I have 2 meanwell 24v powersupplies that have the ground wire on the
> input side also connected to ground.  the output side (phase and
> neutral) are floating relative to ground and not connected to ground
> at all I think.  as the meanwell switching powersupply output should
> be isolated from the input.  I think this is correct
>
> the computer cord ground wire is currently connected to this same
> large copper block.
>
The sheer bulk of that copper bother me a bit because it can function as 
an antenna.  A single bolt, tightened well into the chassis with all the 
connections stacked up on this bolt will be quieter.

> my computer via the 5i25 currently supplies 5v logic power to the 7i76
Thats fine, but if using a std bob on the other 5i25 port, do NOT enable 
the jumper for that port as the bobs std grounding will short circuit 
that, you must supply a separated 5 volts to that bob, or plug in a usb 
cable to steal it from the pc's usb circuitry,
>
> and one of the 24v meanwell powersupplys supplies the 24v field io for
> the 7i76
I have all supplies - outputs tied to ground.  It might work 99% of the 
time without it, till the first nearby lightning strike...  With all 
that grounded, it will probably keep right on working after the strike.

> my encoder problems started when I connected up the servo drive
> simulated encoder output to the 7i76 encoder counter.  I haven't
> connected the 5v and 24 v grounds together.  they did work for awhile
> but don't now

Tie the -'s to the ground bolt. Then do a full powerdown on the whole 
thing, with about a 10 count in the dark, then boot everything back up 
and test it.  And report what you get now...

> I have a 7i89 and 7i84 coming soon and will need a external 5v
> powersupply anyway i think so will change when they arrive here from
> america.
>
> anyway I read your reply and got a bit confused could you read my
> email here and let me know what I need to change and why I should do
> it this way just so I understand.

Basicly, your lack of a common ground has possibly allowed voltages well 
above the breakdown voltages of the chips on these cards, between the - 
connections and a real ground. They all have what can look like an SCR 
as an isolation tub under each transistor its built from, and these 
SCR's can upset the whole thing if they get turned on.  Thats why the 
count to 10 or more powerdown is done, giving these SCR's time enough at 
a low enough voltage to turn them off, at which point the circuit looks 
more normal and may even work. If not, then something has been damaged 
on the card and it should be replaced or tested and repaired as needed 
by Peter. His turnaround time from CA to WV here in the states has been 
very good. Its several thousand miles.  But if I recall correctly, you 
are not exactly local.

> regards
>
> Andrew
>
> On Thu, May 21, 2020 at 9:31 PM Gene Heskett  
wrote:
> > On Thursday 21 May 2020 01:57:06 andrew beck wrote:
> > > hey peter
> > >
> > > I had a look and the unless there is a shorted out pin in the
> > > servo drive connector itself I think the wiring is all good.
> > >
> > > and I highly doubt the servo drive has problems all I did was
> > > connect the 24v back into the servo on pin which is how it has
> > > been running for the last ages.
> > >
> > > anyway how do you recommend commoning the grounds?
> > >
> > > it is as simple as connecting the field power 0v ground with a
> > > wire to the logic power 0v ground?
> >
> > Yes, but how you do it can be very important.
> >
> > In your control box, install a longer bolt, #6 or #8-32 to the
> > chassis. 4mm if metric.
> >
> > Connect all grounds to this bolt, checking that they are not
> > grounded at the far end.  By doing this, you are establishing a
> > single point ground that is the zero volt reference for the whole
> > system. Connect this bolt to the building static ground, the bare
> > wire in most power cabling.
> >
> > Connect the machines frame to this bolt.
> >
> > Connect the - rails of all supplies to this bolt.
> >
> > Connect the - terminals of all cards to this bolt.
> >
> > Break the 3rd pin off the computers supply cable and connect the
> > computers chassis to this bolt. Power the computer not from the
> > wall, but from the same power feeding this box.
> >
> > Connect the shielding of all shielded cabling to this bolt. Do not
> > connect the far end of 

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Peter C. Wallace]

On Fri, 29 May 2020, andrew beck wrote:


Date: Fri, 29 May 2020 10:36:10 +1200
From: andrew beck 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

hey gene

sorry for the slow reply

just getting to this grounding thing now.

currently I have single large copper block with a lot of holes in it for
terminals, this is connected to the earth(ground) wire that goes back to
the whole shed main ground wire rod in the dirt

all my servo drives and vfd main grounds go back to this point as do all
motor grounds etc.  this is how heidenhain set up the machine originally
and they have a whole grounding schematic showing how it all works.  I have
basically copied that.

I have 2 meanwell 24v powersupplies that have the ground wire on the input
side also connected to ground.  the output side (phase and neutral) are
floating relative to ground and not connected to ground at all I think.  as
the meanwell switching powersupply output should be isolated from the
input.  I think this is correct

the computer cord ground wire is currently connected to this same large
copper block.

my computer via the 5i25 currently supplies 5v logic power to the 7i76

and one of the 24v meanwell powersupplys supplies the 24v field io for the
7i76

my encoder problems started when I connected up the servo drive simulated
encoder output to the 7i76 encoder counter.  I haven't connected the 5v and
24 v grounds together.  they did work for awhile but don't now

I have a 7i89 and 7i84 coming soon and will need a external 5v powersupply
anyway i think so will change when they arrive here from america.

anyway I read your reply and got a bit confused could you read my email
here and let me know what I need to change and why I should do it this way
just so I understand.

regards

Andrew



From your symptoms (no signal from A, /A wires) the issue is not likely to be

on the interface side but on the drive or wiring side. One other possibility
is a A, /A short on the 7I76E. This can be ruled out by unplugging the encoder
connector from the 7I76E and re-checking for those signals.




On Thu, May 21, 2020 at 9:31 PM Gene Heskett  wrote:


On Thursday 21 May 2020 01:57:06 andrew beck wrote:


hey peter

I had a look and the unless there is a shorted out pin in the servo
drive connector itself I think the wiring is all good.

and I highly doubt the servo drive has problems all I did was connect
the 24v back into the servo on pin which is how it has been running
for the last ages.

anyway how do you recommend commoning the grounds?

it is as simple as connecting the field power 0v ground with a wire to
the logic power 0v ground?


Yes, but how you do it can be very important.

In your control box, install a longer bolt, #6 or #8-32 to the chassis.
4mm if metric.

Connect all grounds to this bolt, checking that they are not grounded at
the far end.  By doing this, you are establishing a single point ground
that is the zero volt reference for the whole system. Connect this bolt
to the building static ground, the bare wire in most power cabling.

Connect the machines frame to this bolt.

Connect the - rails of all supplies to this bolt.

Connect the - terminals of all cards to this bolt.

Break the 3rd pin off the computers supply cable and connect the
computers chassis to this bolt. Power the computer not from the wall,
but from the same power feeding this box.

Connect the shielding of all shielded cabling to this bolt. Do not
connect the far end of this shielding to anything that is otherwise
grounded.

By making sure these grounds are not connected anyplace else you are
breaking any ground loops which can and will act as antennas to insert
noise into your control signals.

By having this single point ground, a nearby lightning strike can inject
a 100k volt pulse into the system ground as what would be called
a "ground bounce",  but the system will not see it as noise nor be
damaged, because everything is bouncing in unison.

Regardless of what that bolt does during the strike, the 5 volt supply
remains at 5 volts to this bolt, and the 24 volt supply remains at 24
volts to this bolt.

And when the storm is done, your chances of having anything damaged is
reduced to the vanishing point.

Stay well Andrew.

[...]

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

hey gene

sorry for the slow reply

just getting to this grounding thing now.

currently I have single large copper block with a lot of holes in it for
terminals, this is connected to the earth(ground) wire that goes back to
the whole shed main ground wire rod in the dirt

all my servo drives and vfd main grounds go back to this point as do all
motor grounds etc.  this is how heidenhain set up the machine originally
and they have a whole grounding schematic showing how it all works.  I have
basically copied that.

I have 2 meanwell 24v powersupplies that have the ground wire on the input
side also connected to ground.  the output side (phase and neutral) are
floating relative to ground and not connected to ground at all I think.  as
the meanwell switching powersupply output should be isolated from the
input.  I think this is correct

the computer cord ground wire is currently connected to this same large
copper block.

my computer via the 5i25 currently supplies 5v logic power to the 7i76

and one of the 24v meanwell powersupplys supplies the 24v field io for the
7i76

my encoder problems started when I connected up the servo drive simulated
encoder output to the 7i76 encoder counter.  I haven't connected the 5v and
24 v grounds together.  they did work for awhile but don't now

I have a 7i89 and 7i84 coming soon and will need a external 5v powersupply
anyway i think so will change when they arrive here from america.

anyway I read your reply and got a bit confused could you read my email
here and let me know what I need to change and why I should do it this way
just so I understand.

regards

Andrew

On Thu, May 21, 2020 at 9:31 PM Gene Heskett  wrote:

> On Thursday 21 May 2020 01:57:06 andrew beck wrote:
>
> > hey peter
> >
> > I had a look and the unless there is a shorted out pin in the servo
> > drive connector itself I think the wiring is all good.
> >
> > and I highly doubt the servo drive has problems all I did was connect
> > the 24v back into the servo on pin which is how it has been running
> > for the last ages.
> >
> > anyway how do you recommend commoning the grounds?
> >
> > it is as simple as connecting the field power 0v ground with a wire to
> > the logic power 0v ground?
> >
> Yes, but how you do it can be very important.
>
> In your control box, install a longer bolt, #6 or #8-32 to the chassis.
> 4mm if metric.
>
> Connect all grounds to this bolt, checking that they are not grounded at
> the far end.  By doing this, you are establishing a single point ground
> that is the zero volt reference for the whole system. Connect this bolt
> to the building static ground, the bare wire in most power cabling.
>
> Connect the machines frame to this bolt.
>
> Connect the - rails of all supplies to this bolt.
>
> Connect the - terminals of all cards to this bolt.
>
> Break the 3rd pin off the computers supply cable and connect the
> computers chassis to this bolt. Power the computer not from the wall,
> but from the same power feeding this box.
>
> Connect the shielding of all shielded cabling to this bolt. Do not
> connect the far end of this shielding to anything that is otherwise
> grounded.
>
> By making sure these grounds are not connected anyplace else you are
> breaking any ground loops which can and will act as antennas to insert
> noise into your control signals.
>
> By having this single point ground, a nearby lightning strike can inject
> a 100k volt pulse into the system ground as what would be called
> a "ground bounce",  but the system will not see it as noise nor be
> damaged, because everything is bouncing in unison.
>
> Regardless of what that bolt does during the strike, the 5 volt supply
> remains at 5 volts to this bolt, and the 24 volt supply remains at 24
> volts to this bolt.
>
> And when the storm is done, your chances of having anything damaged is
> reduced to the vanishing point.
>
> Stay well Andrew.
>
> [...]
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Gene Heskett]

On Thursday 21 May 2020 01:57:06 andrew beck wrote:

> hey peter
>
> I had a look and the unless there is a shorted out pin in the servo
> drive connector itself I think the wiring is all good.
>
> and I highly doubt the servo drive has problems all I did was connect
> the 24v back into the servo on pin which is how it has been running
> for the last ages.
>
> anyway how do you recommend commoning the grounds?
>
> it is as simple as connecting the field power 0v ground with a wire to
> the logic power 0v ground?
>
Yes, but how you do it can be very important.

In your control box, install a longer bolt, #6 or #8-32 to the chassis. 
4mm if metric.

Connect all grounds to this bolt, checking that they are not grounded at 
the far end.  By doing this, you are establishing a single point ground 
that is the zero volt reference for the whole system. Connect this bolt 
to the building static ground, the bare wire in most power cabling.

Connect the machines frame to this bolt.

Connect the - rails of all supplies to this bolt.

Connect the - terminals of all cards to this bolt.

Break the 3rd pin off the computers supply cable and connect the 
computers chassis to this bolt. Power the computer not from the wall, 
but from the same power feeding this box. 

Connect the shielding of all shielded cabling to this bolt. Do not 
connect the far end of this shielding to anything that is otherwise 
grounded.

By making sure these grounds are not connected anyplace else you are 
breaking any ground loops which can and will act as antennas to insert 
noise into your control signals.

By having this single point ground, a nearby lightning strike can inject 
a 100k volt pulse into the system ground as what would be called 
a "ground bounce",  but the system will not see it as noise nor be 
damaged, because everything is bouncing in unison.

Regardless of what that bolt does during the strike, the 5 volt supply 
remains at 5 volts to this bolt, and the 24 volt supply remains at 24 
volts to this bolt. 

And when the storm is done, your chances of having anything damaged is 
reduced to the vanishing point.

Stay well Andrew.

[...]

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

hey peter

I had a look and the unless there is a shorted out pin in the servo drive
connector itself I think the wiring is all good.

and I highly doubt the servo drive has problems all I did was connect the
24v back into the servo on pin which is how it has been running for the
last ages.

anyway how do you recommend commoning the grounds?

it is as simple as connecting the field power 0v ground with a wire to the
logic power 0v ground?

regards

Andrew

On Thu, May 21, 2020 at 4:26 PM andrew beck 
wrote:

> the 24v common is currently not connected to the frame ground.  It is
> floating.  well the meanwell powersupply has a ground terminal on the input
> side that is connected to machine ground.  but the output side is
> completely unconnected eg the 24 v and 0v are floating
>
> I will double check the wiring and check if there is a problem
>
>
> On Thu, May 21, 2020 at 4:22 PM Peter C. Wallace  wrote:
>
>> On Thu, 21 May 2020, andrew beck wrote:
>>
>> > Date: Thu, 21 May 2020 15:53:45 +1200
>> > From: andrew beck 
>> > Reply-To: "Enhanced Machine Controller (EMC)"
>> > 
>> > To: "Enhanced Machine Controller (EMC)" <
>> emc-users@lists.sourceforge.net>
>> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
>> >
>> > hey PCW and andy
>> >
>> > I just checked the mpg with a multimeter.
>> >
>> > I had my brother jogging .005mm at a time to try and catch the encoder
>> > pulses.
>> >
>> > when measuring between the B and /B pulses I could measure 2.5 volts
>> when
>> > the encoder triggered.
>> >
>> > I could not measure any voltage at any time through the A and /A
>> channels.
>> >
>>
>> Broken wire or connecoto problem?
>>
>> > PCW how do I common the 5v and 24v grounds together on the 7i76?
>> >
>> > I saw this sheet here for the 7i76E that seems to show that the 7i76E
>> only
>> > needs 24v and makes its own 5v if you set the jumpers right.  (is the
>> 7i76
>> > also the same?)  that would make life really easy
>>
>> No its normally suggested to have the 7I76 use FPGA power
>>
>> >
>> > [image: image.png]
>> >
>> > If I do have to use a separate 5v powersupply eg 5i25 for now can I just
>> > connect a wire between 24v ground and a unused logic 0v ground pin on a
>> > step gen port or something?  Or should I do something more elegant
>> >
>> I would check to see if the 24V common is already connected to frame
>> ground
>> if it is you should be OK
>>
>> > regards
>> >
>> > Andrew
>> >
>> > On Thu, May 21, 2020 at 3:19 PM andrew beck 
>> > wrote:
>> >
>> >> hey peter I will check that now before I put the machine together
>> >> again without the encoder config to make parts again
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> On Thu, May 21, 2020 at 3:05 PM Peter C. Wallace 
>> wrote:
>> >>
>> >>> On Thu, 21 May 2020, andrew beck wrote:
>> >>>
>> >>>> Date: Thu, 21 May 2020 14:05:02 +1200
>> >>>> From: andrew beck 
>> >>>> Reply-To: "Enhanced Machine Controller (EMC)"
>> >>>> 
>> >>>> To: "Enhanced Machine Controller (EMC)" <
>> >>> emc-users@lists.sourceforge.net>
>> >>>> Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting
>> suddenly
>> >>>>
>> >>>> hey peter
>> >>>>
>> >>>> I am using a 5i25 and 7i76 combo.  and currently supplying power
>> from the
>> >>>> 5i25
>> >>>>
>> >>>> so I don't particularly want to make the computer ground the same as
>> >>>> everything else lol.
>> >>>>
>> >>>
>> >>> Except the the computer ground is frame ground and the common for the
>> >>> servo
>> >>> drive quadrature outputs should also be returned to frame ground
>> >>>
>> >>>> it sounds like I need to connect a external 5v powersupply up to the
>> 7i76
>> >>>> and change the jumpers around to suit.  and then connect up
>> everything
>> >>>> again.
>> >>>
>> >>> That will not change anything ground related
>> >>>>
>> >>>> I have a

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

the 24v common is currently not connected to the frame ground.  It is
floating.  well the meanwell powersupply has a ground terminal on the input
side that is connected to machine ground.  but the output side is
completely unconnected eg the 24 v and 0v are floating

I will double check the wiring and check if there is a problem


On Thu, May 21, 2020 at 4:22 PM Peter C. Wallace  wrote:

> On Thu, 21 May 2020, andrew beck wrote:
>
> > Date: Thu, 21 May 2020 15:53:45 +1200
> > From: andrew beck 
> > Reply-To: "Enhanced Machine Controller (EMC)"
> > 
> > To: "Enhanced Machine Controller (EMC)"  >
> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
> >
> > hey PCW and andy
> >
> > I just checked the mpg with a multimeter.
> >
> > I had my brother jogging .005mm at a time to try and catch the encoder
> > pulses.
> >
> > when measuring between the B and /B pulses I could measure 2.5 volts when
> > the encoder triggered.
> >
> > I could not measure any voltage at any time through the A and /A
> channels.
> >
>
> Broken wire or connecoto problem?
>
> > PCW how do I common the 5v and 24v grounds together on the 7i76?
> >
> > I saw this sheet here for the 7i76E that seems to show that the 7i76E
> only
> > needs 24v and makes its own 5v if you set the jumpers right.  (is the
> 7i76
> > also the same?)  that would make life really easy
>
> No its normally suggested to have the 7I76 use FPGA power
>
> >
> > [image: image.png]
> >
> > If I do have to use a separate 5v powersupply eg 5i25 for now can I just
> > connect a wire between 24v ground and a unused logic 0v ground pin on a
> > step gen port or something?  Or should I do something more elegant
> >
> I would check to see if the 24V common is already connected to frame ground
> if it is you should be OK
>
> > regards
> >
> > Andrew
> >
> > On Thu, May 21, 2020 at 3:19 PM andrew beck 
> > wrote:
> >
> >> hey peter I will check that now before I put the machine together
> >> again without the encoder config to make parts again
> >>
> >>
> >>
> >>
> >>
> >> On Thu, May 21, 2020 at 3:05 PM Peter C. Wallace 
> wrote:
> >>
> >>> On Thu, 21 May 2020, andrew beck wrote:
> >>>
> >>>> Date: Thu, 21 May 2020 14:05:02 +1200
> >>>> From: andrew beck 
> >>>> Reply-To: "Enhanced Machine Controller (EMC)"
> >>>> 
> >>>> To: "Enhanced Machine Controller (EMC)" <
> >>> emc-users@lists.sourceforge.net>
> >>>> Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting
> suddenly
> >>>>
> >>>> hey peter
> >>>>
> >>>> I am using a 5i25 and 7i76 combo.  and currently supplying power from
> the
> >>>> 5i25
> >>>>
> >>>> so I don't particularly want to make the computer ground the same as
> >>>> everything else lol.
> >>>>
> >>>
> >>> Except the the computer ground is frame ground and the common for the
> >>> servo
> >>> drive quadrature outputs should also be returned to frame ground
> >>>
> >>>> it sounds like I need to connect a external 5v powersupply up to the
> 7i76
> >>>> and change the jumpers around to suit.  and then connect up everything
> >>>> again.
> >>>
> >>> That will not change anything ground related
> >>>>
> >>>> I have a 7i89 coming soon and I will wait until then to sort this out
> I
> >>>> think.  I will just disconnect the encoder feedback for now and make
> some
> >>>> parts.
> >>>>
> >>>> as my servo drives are tuned now.
> >>>>
> >>>>
> >>>>
> >>>> its a bit silly that it only just now failed though.  it was working
> >>>> perfectly yesterday.
> >>>> regards
> >>>>
> >>>> Andrew
> >>>
> >>> Do you have valid differential signals across the A /A and B /B pairs?
> >>>
> >>>   ( >2 V absolute across the pins, that is more positive than +2V or
> more
> >>> negative than -2V )
> >>>
> >>> Thats would be the most diagnostic test
> >>>
> >>>
> >>> On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace 
> wro

Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Peter C. Wallace]

On Thu, 21 May 2020, andrew beck wrote:


Date: Thu, 21 May 2020 15:53:45 +1200
From: andrew beck 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

hey PCW and andy

I just checked the mpg with a multimeter.

I had my brother jogging .005mm at a time to try and catch the encoder
pulses.

when measuring between the B and /B pulses I could measure 2.5 volts when
the encoder triggered.

I could not measure any voltage at any time through the A and /A channels.



Broken wire or connecoto problem?


PCW how do I common the 5v and 24v grounds together on the 7i76?

I saw this sheet here for the 7i76E that seems to show that the 7i76E only
needs 24v and makes its own 5v if you set the jumpers right.  (is the 7i76
also the same?)  that would make life really easy


No its normally suggested to have the 7I76 use FPGA power



[image: image.png]

If I do have to use a separate 5v powersupply eg 5i25 for now can I just
connect a wire between 24v ground and a unused logic 0v ground pin on a
step gen port or something?  Or should I do something more elegant


I would check to see if the 24V common is already connected to frame ground
if it is you should be OK


regards

Andrew

On Thu, May 21, 2020 at 3:19 PM andrew beck 
wrote:


hey peter I will check that now before I put the machine together
again without the encoder config to make parts again





On Thu, May 21, 2020 at 3:05 PM Peter C. Wallace  wrote:


On Thu, 21 May 2020, andrew beck wrote:


Date: Thu, 21 May 2020 14:05:02 +1200
From: andrew beck 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" <

emc-users@lists.sourceforge.net>

Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

hey peter

I am using a 5i25 and 7i76 combo.  and currently supplying power from the
5i25

so I don't particularly want to make the computer ground the same as
everything else lol.



Except the the computer ground is frame ground and the common for the
servo
drive quadrature outputs should also be returned to frame ground


it sounds like I need to connect a external 5v powersupply up to the 7i76
and change the jumpers around to suit.  and then connect up everything
again.


That will not change anything ground related


I have a 7i89 coming soon and I will wait until then to sort this out I
think.  I will just disconnect the encoder feedback for now and make some
parts.

as my servo drives are tuned now.



its a bit silly that it only just now failed though.  it was working
perfectly yesterday.
regards

Andrew


Do you have valid differential signals across the A /A and B /B pairs?

  ( >2 V absolute across the pins, that is more positive than +2V or more
negative than -2V )

Thats would be the most diagnostic test


On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace  wrote:


On Thu, 21 May 2020, andy pugh wrote:


Date: Thu, 21 May 2020 02:33:16 +0100
From: andy pugh 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" <

emc-users@lists.sourceforge.net


Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting

suddenly


On Thu, 21 May 2020 at 02:22, andrew beck 

wrote:


I read a post you made while ago saying that the 5v and 24v

powersupplies

need to be within a certain threshold to work well.  or else they

need

to

be commoned together



This is really a question for PCW. I think that they need to be within
12 (17?) volts to work.


There should be no substantial common mode voltage. That is the
quadrature source and the 7I76E must have a common ground.

The input common mode range on the 7I76E encoder input is -7 to +12V
you can easily exceed this (and even damage the reciever chip)
if the source and 7I76E do not have a common grouns



so if I test between the 7i76 mesa 24 field power ground ( this is

the

same

power as the servo drive control power)  and the logic 0v on 7i76 I

should

get close to 0v  is that correct?



The important thing is that the difference between + and - is a couple
of volts or so (positive or negative) and in both states the
difference between each input and 7i76 gnd is <12V (or possibly 17,
the number is in the manual)



--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
 George Fitch, Atlanta Constitution Newspaper, 1912


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Mesa Electronics

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(")_(") signature to help him gain world domination.
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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

hey peter I will check that now before I put the machine together
again without the encoder config to make parts again





On Thu, May 21, 2020 at 3:05 PM Peter C. Wallace  wrote:

> On Thu, 21 May 2020, andrew beck wrote:
>
> > Date: Thu, 21 May 2020 14:05:02 +1200
> > From: andrew beck 
> > Reply-To: "Enhanced Machine Controller (EMC)"
> > 
> > To: "Enhanced Machine Controller (EMC)"  >
> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
> >
> > hey peter
> >
> >I am using a 5i25 and 7i76 combo.  and currently supplying power from the
> >5i25
> >
> >so I don't particularly want to make the computer ground the same as
> >everything else lol.
> >
>
> Except the the computer ground is frame ground and the common for the
> servo
> drive quadrature outputs should also be returned to frame ground
>
> >it sounds like I need to connect a external 5v powersupply up to the 7i76
> >and change the jumpers around to suit.  and then connect up everything
> >again.
>
> That will not change anything ground related
> >
> >I have a 7i89 coming soon and I will wait until then to sort this out I
> >think.  I will just disconnect the encoder feedback for now and make some
> >parts.
> >
> >as my servo drives are tuned now.
> >
> >
> >
> >its a bit silly that it only just now failed though.  it was working
> >perfectly yesterday.
> >regards
> >
> >Andrew
>
> Do you have valid differential signals across the A /A and B /B pairs?
>
>   ( >2 V absolute across the pins, that is more positive than +2V or more
> negative than -2V )
>
> Thats would be the most diagnostic test
>
>
> On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace  wrote:
>
> > On Thu, 21 May 2020, andy pugh wrote:
> >
> > > Date: Thu, 21 May 2020 02:33:16 +0100
> > > From: andy pugh 
> > > Reply-To: "Enhanced Machine Controller (EMC)"
> > > 
> > > To: "Enhanced Machine Controller (EMC)" <
> emc-users@lists.sourceforge.net
> > >
> > > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting
> suddenly
> > >
> > > On Thu, 21 May 2020 at 02:22, andrew beck 
> > wrote:
> >
> > >> I read a post you made while ago saying that the 5v and 24v
> > powersupplies
> > >> need to be within a certain threshold to work well.  or else they need
> > to
> > >> be commoned together
> >
> > >This is really a question for PCW. I think that they need to be within
> > >12 (17?) volts to work.
> >
> > There should be no substantial common mode voltage. That is the
> > quadrature source and the 7I76E must have a common ground.
> >
> > The input common mode range on the 7I76E encoder input is -7 to +12V
> > you can easily exceed this (and even damage the reciever chip)
> > if the source and 7I76E do not have a common grouns
> >
> >
> > >> so if I test between the 7i76 mesa 24 field power ground ( this is the
> > same
> > >> power as the servo drive control power)  and the logic 0v on 7i76 I
> > should
> > >> get close to 0v  is that correct?
> >
> > >The important thing is that the difference between + and - is a couple
> > >of volts or so (positive or negative) and in both states the
> > >difference between each input and 7i76 gnd is <12V (or possibly 17,
> > >the number is in the manual)
> >
> >
> > --
> > atp
> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > designed for the especial use of mechanical geniuses, daredevils and
> > lunatics."
> >  George Fitch, Atlanta Constitution Newspaper, 1912
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> > Peter Wallace
> > Mesa Electronics
> >
> > (\__/)
> > (='.'=) This is Bunny. Copy and paste bunny into your
> > (")_(") signature to help him gain world domination.
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
> ___
> Emc-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>
> Peter Wallace
> Mesa Electronics
>
> (\__/)
> (='.'=) This is Bunny. Copy and paste bunny into your
> (")_(") signature to help him gain world domination.
> ___
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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Peter C. Wallace]

On Thu, 21 May 2020, andrew beck wrote:


Date: Thu, 21 May 2020 14:05:02 +1200
From: andrew beck 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

hey peter

I am using a 5i25 and 7i76 combo.  and currently supplying power from the
5i25

so I don't particularly want to make the computer ground the same as
everything else lol.



Except the the computer ground is frame ground and the common for the servo 
drive quadrature outputs should also be returned to frame ground



it sounds like I need to connect a external 5v powersupply up to the 7i76
and change the jumpers around to suit.  and then connect up everything
again.


That will not change anything ground related


I have a 7i89 coming soon and I will wait until then to sort this out I
think.  I will just disconnect the encoder feedback for now and make some
parts.

as my servo drives are tuned now.



its a bit silly that it only just now failed though.  it was working
perfectly yesterday.
regards

Andrew


Do you have valid differential signals across the A /A and B /B pairs?

 ( >2 V absolute across the pins, that is more positive than +2V or more 
negative than -2V )


Thats would be the most diagnostic test


On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace  wrote:


On Thu, 21 May 2020, andy pugh wrote:

> Date: Thu, 21 May 2020 02:33:16 +0100
> From: andy pugh 
> Reply-To: "Enhanced Machine Controller (EMC)"
> 
> To: "Enhanced Machine Controller (EMC)" 
> Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
>
> On Thu, 21 May 2020 at 02:22, andrew beck 
wrote:

>> I read a post you made while ago saying that the 5v and 24v
powersupplies
>> need to be within a certain threshold to work well.  or else they need
to
>> be commoned together

>This is really a question for PCW. I think that they need to be within
>12 (17?) volts to work.

There should be no substantial common mode voltage. That is the
quadrature source and the 7I76E must have a common ground.

The input common mode range on the 7I76E encoder input is -7 to +12V
you can easily exceed this (and even damage the reciever chip)
if the source and 7I76E do not have a common grouns


>> so if I test between the 7i76 mesa 24 field power ground ( this is the
same
>> power as the servo drive control power)  and the logic 0v on 7i76 I
should
>> get close to 0v  is that correct?

>The important thing is that the difference between + and - is a couple
>of volts or so (positive or negative) and in both states the
>difference between each input and 7i76 gnd is <12V (or possibly 17,
>the number is in the manual)


--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
 George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

andy and PCW thanks so much for the help.

I will be back in touch when my other cards come  I will probably just
update my build thread on the forum so that the next person having issues
can seach the posts for my issue

regards

Andrew

On Thu, May 21, 2020 at 2:05 PM andrew beck 
wrote:

> hey peter
>
> I am using a 5i25 and 7i76 combo.  and currently supplying power from the
> 5i25
>
> so I don't particularly want to make the computer ground the same as
> everything else lol.
>
> it sounds like I need to connect a external 5v powersupply up to the 7i76
> and change the jumpers around to suit.  and then connect up everything
> again.
>
> I have a 7i89 coming soon and I will wait until then to sort this out I
> think.  I will just disconnect the encoder feedback for now and make some
> parts.
>
> as my servo drives are tuned now.
>
>
>
> its a bit silly that it only just now failed though.  it was working
> perfectly yesterday.
> regards
>
> Andrew
>
> On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace  wrote:
>
>> On Thu, 21 May 2020, andy pugh wrote:
>>
>> > Date: Thu, 21 May 2020 02:33:16 +0100
>> > From: andy pugh 
>> > Reply-To: "Enhanced Machine Controller (EMC)"
>> >     
>> > To: "Enhanced Machine Controller (EMC)" <
>> emc-users@lists.sourceforge.net>
>> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
>> >
>> > On Thu, 21 May 2020 at 02:22, andrew beck 
>> wrote:
>>
>> >> I read a post you made while ago saying that the 5v and 24v
>> powersupplies
>> >> need to be within a certain threshold to work well.  or else they need
>> to
>> >> be commoned together
>>
>> >This is really a question for PCW. I think that they need to be within
>> >12 (17?) volts to work.
>>
>> There should be no substantial common mode voltage. That is the
>> quadrature source and the 7I76E must have a common ground.
>>
>> The input common mode range on the 7I76E encoder input is -7 to +12V
>> you can easily exceed this (and even damage the reciever chip)
>> if the source and 7I76E do not have a common grouns
>>
>>
>> >> so if I test between the 7i76 mesa 24 field power ground ( this is the
>> same
>> >> power as the servo drive control power)  and the logic 0v on 7i76 I
>> should
>> >> get close to 0v  is that correct?
>>
>> >The important thing is that the difference between + and - is a couple
>> >of volts or so (positive or negative) and in both states the
>> >difference between each input and 7i76 gnd is <12V (or possibly 17,
>> >the number is in the manual)
>>
>>
>> --
>> atp
>> "A motorcycle is a bicycle with a pandemonium attachment and is
>> designed for the especial use of mechanical geniuses, daredevils and
>> lunatics."
>> яя George Fitch, Atlanta Constitution Newspaper, 1912
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>> Peter Wallace
>> Mesa Electronics
>>
>> (\__/)
>> (='.'=) This is Bunny. Copy and paste bunny into your
>> (")_(") signature to help him gain world domination.
>> ___
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>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>

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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

hey peter

I am using a 5i25 and 7i76 combo.  and currently supplying power from the
5i25

so I don't particularly want to make the computer ground the same as
everything else lol.

it sounds like I need to connect a external 5v powersupply up to the 7i76
and change the jumpers around to suit.  and then connect up everything
again.

I have a 7i89 coming soon and I will wait until then to sort this out I
think.  I will just disconnect the encoder feedback for now and make some
parts.

as my servo drives are tuned now.



its a bit silly that it only just now failed though.  it was working
perfectly yesterday.
regards

Andrew

On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace  wrote:

> On Thu, 21 May 2020, andy pugh wrote:
>
> > Date: Thu, 21 May 2020 02:33:16 +0100
> > From: andy pugh 
> > Reply-To: "Enhanced Machine Controller (EMC)"
> > 
> > To: "Enhanced Machine Controller (EMC)"  >
> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
> >
> > On Thu, 21 May 2020 at 02:22, andrew beck 
> wrote:
>
> >> I read a post you made while ago saying that the 5v and 24v
> powersupplies
> >> need to be within a certain threshold to work well.  or else they need
> to
> >> be commoned together
>
> >This is really a question for PCW. I think that they need to be within
> >12 (17?) volts to work.
>
> There should be no substantial common mode voltage. That is the
> quadrature source and the 7I76E must have a common ground.
>
> The input common mode range on the 7I76E encoder input is -7 to +12V
> you can easily exceed this (and even damage the reciever chip)
> if the source and 7I76E do not have a common grouns
>
>
> >> so if I test between the 7i76 mesa 24 field power ground ( this is the
> same
> >> power as the servo drive control power)  and the logic 0v on 7i76 I
> should
> >> get close to 0v  is that correct?
>
> >The important thing is that the difference between + and - is a couple
> >of volts or so (positive or negative) and in both states the
> >difference between each input and 7i76 gnd is <12V (or possibly 17,
> >the number is in the manual)
>
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> яя George Fitch, Atlanta Constitution Newspaper, 1912
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
> Peter Wallace
> Mesa Electronics
>
> (\__/)
> (='.'=) This is Bunny. Copy and paste bunny into your
> (")_(") signature to help him gain world domination.
> ___
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Peter C. Wallace]

On Thu, 21 May 2020, andrew beck wrote:


Date: Thu, 21 May 2020 13:44:03 +1200
From: andrew beck 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

actually I just found the A and B inputs in the Hal configuration window

the B input changes from red to yellow if I put some force on the table and
try move it slowly.

but the A input doesn't change color at all.

is that expected with a problem like this?


Yes, if the raw counts only change going back and forth by 1, it usually means A 
or B is not changing




thanks for the reply PCW

hey is that different to just checking the raw count in Hal?

what pin am I looking for?  and can I monitor it from the Hal
configuration window?

regards

Andrew

On Thu, May 21, 2020 at 1:36 PM Peter C. Wallace  wrote:


On Thu, 21 May 2020, andy pugh wrote:

>> Date: Thu, 21 May 2020 02:21:02 +0100
>> From: andy pugh 
>> Reply-To: "Enhanced Machine Controller (EMC)"
>> 
>> To: "Enhanced Machine Controller (EMC)" <
emc-users@lists.sourceforge.net>
>> Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting
suddenly
>>
>> On Thu, 21 May 2020 at 02:14, andrew beck 
wrote:

>> I am wired up with differential twisted pairs.

>That's a good start.

>> also the 5i25 is connected powering the 7i76 spindle encoder power
which I
>> am using (I don't have a external 5v powersupply.

>If you put a multimeter on the A+ / A- and B+ / B- pairs at the 7i76
>termianls and turn the encoder slowly, what do you see?

>(also check that all wires are in the clamp. not under the clamp...)


You should also be able to tell whether A or B is not changing
by looking at the encoder A,B pins in hal


--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
 George Fitch, Atlanta Constitution Newspaper, 191


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Peter C. Wallace]

On Thu, 21 May 2020, andrew beck wrote:


Date: Thu, 21 May 2020 13:38:08 +1200
From: andrew beck 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

thanks for the reply PCW



hey is that different to just checking the raw count in Hal?


Yes because you can tell which of A or B is not working


what pin am I looking for?  and can I monitor it from the Hal configuration
window?


hm2_7i76e.0.encoder.00.input-a
hm2_7i76e.0.encoder.00.input-b





regards

Andrew


On Thu, May 21, 2020 at 1:36 PM Peter C. Wallace  wrote:


On Thu, 21 May 2020, andy pugh wrote:

>> Date: Thu, 21 May 2020 02:21:02 +0100
>> From: andy pugh 
>> Reply-To: "Enhanced Machine Controller (EMC)"
>> 
>> To: "Enhanced Machine Controller (EMC)" <
emc-users@lists.sourceforge.net>
>> Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
>>
>> On Thu, 21 May 2020 at 02:14, andrew beck 
wrote:

>> I am wired up with differential twisted pairs.

>That's a good start.

>> also the 5i25 is connected powering the 7i76 spindle encoder power
which I
>> am using (I don't have a external 5v powersupply.

>If you put a multimeter on the A+ / A- and B+ / B- pairs at the 7i76
>termianls and turn the encoder slowly, what do you see?

>(also check that all wires are in the clamp. not under the clamp...)


You should also be able to tell whether A or B is not changing
by looking at the encoder A,B pins in hal


--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
 George Fitch, Atlanta Constitution Newspaper, 191


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Peter C. Wallace]

On Thu, 21 May 2020, andy pugh wrote:


Date: Thu, 21 May 2020 02:33:16 +0100
From: andy pugh 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

On Thu, 21 May 2020 at 02:22, andrew beck  wrote:



I read a post you made while ago saying that the 5v and 24v powersupplies
need to be within a certain threshold to work well.  or else they need to
be commoned together



This is really a question for PCW. I think that they need to be within
12 (17?) volts to work.


There should be no substantial common mode voltage. That is the 
quadrature source and the 7I76E must have a common ground.


The input common mode range on the 7I76E encoder input is -7 to +12V
you can easily exceed this (and even damage the reciever chip)
if the source and 7I76E do not have a common grouns



so if I test between the 7i76 mesa 24 field power ground ( this is the same
power as the servo drive control power)  and the logic 0v on 7i76 I should
get close to 0v  is that correct?



The important thing is that the difference between + and - is a couple
of volts or so (positive or negative) and in both states the
difference between each input and 7i76 gnd is <12V (or possibly 17,
the number is in the manual)



--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
?? George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

actually I just found the A and B inputs in the Hal configuration window

the B input changes from red to yellow if I put some force on the table and
try move it slowly.

 but the A input doesn't change color at all.

is that expected with a problem like this?



On Thu, May 21, 2020 at 1:38 PM andrew beck 
wrote:

> thanks for the reply PCW
>
> hey is that different to just checking the raw count in Hal?
>
> what pin am I looking for?  and can I monitor it from the Hal
> configuration window?
>
> regards
>
> Andrew
>
> On Thu, May 21, 2020 at 1:36 PM Peter C. Wallace  wrote:
>
>> On Thu, 21 May 2020, andy pugh wrote:
>>
>> >> Date: Thu, 21 May 2020 02:21:02 +0100
>> >> From: andy pugh 
>> >> Reply-To: "Enhanced Machine Controller (EMC)"
>> >>     
>> >> To: "Enhanced Machine Controller (EMC)" <
>> emc-users@lists.sourceforge.net>
>> >> Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting
>> suddenly
>> >>
>> >> On Thu, 21 May 2020 at 02:14, andrew beck 
>> wrote:
>>
>> >> I am wired up with differential twisted pairs.
>>
>> >That's a good start.
>>
>> >> also the 5i25 is connected powering the 7i76 spindle encoder power
>> which I
>> >> am using (I don't have a external 5v powersupply.
>>
>> >If you put a multimeter on the A+ / A- and B+ / B- pairs at the 7i76
>> >termianls and turn the encoder slowly, what do you see?
>>
>> >(also check that all wires are in the clamp. not under the clamp...)
>>
>>
>> You should also be able to tell whether A or B is not changing
>> by looking at the encoder A,B pins in hal
>>
>>
>> --
>> atp
>> "A motorcycle is a bicycle with a pandemonium attachment and is
>> designed for the especial use of mechanical geniuses, daredevils and
>> lunatics."
>> яя George Fitch, Atlanta Constitution Newspaper, 191
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>> Peter Wallace
>> Mesa Electronics
>>
>> (\__/)
>> (='.'=) This is Bunny. Copy and paste bunny into your
>> (")_(") signature to help him gain world domination.
>> ___
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>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>

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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

thanks for the reply PCW

hey is that different to just checking the raw count in Hal?

what pin am I looking for?  and can I monitor it from the Hal configuration
window?

regards

Andrew

On Thu, May 21, 2020 at 1:36 PM Peter C. Wallace  wrote:

> On Thu, 21 May 2020, andy pugh wrote:
>
> >> Date: Thu, 21 May 2020 02:21:02 +0100
> >> From: andy pugh 
> >> Reply-To: "Enhanced Machine Controller (EMC)"
> >> 
> >> To: "Enhanced Machine Controller (EMC)" <
> emc-users@lists.sourceforge.net>
> >> Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
> >>
> >> On Thu, 21 May 2020 at 02:14, andrew beck 
> wrote:
>
> >> I am wired up with differential twisted pairs.
>
> >That's a good start.
>
> >> also the 5i25 is connected powering the 7i76 spindle encoder power
> which I
> >> am using (I don't have a external 5v powersupply.
>
> >If you put a multimeter on the A+ / A- and B+ / B- pairs at the 7i76
> >termianls and turn the encoder slowly, what do you see?
>
> >(also check that all wires are in the clamp. not under the clamp...)
>
>
> You should also be able to tell whether A or B is not changing
> by looking at the encoder A,B pins in hal
>
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> яя George Fitch, Atlanta Constitution Newspaper, 191
>
>
> ___
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>
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> Mesa Electronics
>
> (\__/)
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> (")_(") signature to help him gain world domination.
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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Peter C. Wallace]

On Thu, 21 May 2020, andy pugh wrote:


Date: Thu, 21 May 2020 02:21:02 +0100
From: andy pugh 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

On Thu, 21 May 2020 at 02:14, andrew beck  wrote:



I am wired up with differential twisted pairs.



That's a good start.



also the 5i25 is connected powering the 7i76 spindle encoder power which I
am using (I don't have a external 5v powersupply.



If you put a multimeter on the A+ / A- and B+ / B- pairs at the 7i76
termianls and turn the encoder slowly, what do you see?



(also check that all wires are in the clamp. not under the clamp...)



You should also be able to tell whether A or B is not changing
by looking at the encoder A,B pins in hal


--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
?? George Fitch, Atlanta Constitution Newspaper, 191


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

hey andy

just to make this crystal clear

do you want me to check with a multimeter between A+/A- and then afterwards
separately check between B+/B-

that will be slightly hard to do as the encoder is a simulated output or
something from the servo drive..

I might need to get another person to help here.

Or I could disconnect the encoder in hal and then command a really slow
feed for and go behind the machine and test it while it is running to test

On Thu, May 21, 2020 at 1:23 PM andy pugh  wrote:

> On Thu, 21 May 2020 at 02:14, andrew beck 
> wrote:
>
> > I am wired up with differential twisted pairs.
>
> That's a good start.
>
> > also the 5i25 is connected powering the 7i76 spindle encoder power which
> I
> > am using (I don't have a external 5v powersupply.
>
> If you put a multimeter on the A+ / A- and B+ / B- pairs at the 7i76
> termianls and turn the encoder slowly, what do you see?
>
> (also check that all wires are in the clamp. not under the clamp...)
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 191
>
>
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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andy pugh]

On Thu, 21 May 2020 at 02:22, andrew beck  wrote:

> I read a post you made while ago saying that the 5v and 24v powersupplies
> need to be within a certain threshold to work well.  or else they need to
> be commoned together

This is really a question for PCW. I think that they need to be within
12 (17?) volts to work.

> so if I test between the 7i76 mesa 24 field power ground ( this is the same
> power as the servo drive control power)  and the logic 0v on 7i76 I should
> get close to 0v  is that correct?

The important thing is that the difference between + and - is a couple
of volts or so (positive or negative) and in both states the
difference between each input and 7i76 gnd is <12V (or possibly 17,
the number is in the manual)


-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andy pugh]

On Thu, 21 May 2020 at 02:14, andrew beck  wrote:

> I am wired up with differential twisted pairs.

That's a good start.

> also the 5i25 is connected powering the 7i76 spindle encoder power which I
> am using (I don't have a external 5v powersupply.

If you put a multimeter on the A+ / A- and B+ / B- pairs at the 7i76
termianls and turn the encoder slowly, what do you see?

(also check that all wires are in the clamp. not under the clamp...)

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 191


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

I read a post you made while ago saying that the 5v and 24v powersupplies
need to be within a certain threshold to work well.  or else they need to
be commoned together

so if I test between the 7i76 mesa 24 field power ground ( this is the same
power as the servo drive control power)  and the logic 0v on 7i76 I should
get close to 0v  is that correct?

regards

Andrew

On Thu, May 21, 2020 at 1:12 PM andrew beck 
wrote:

> hey andy thanks for the quick reply.
>
> I am wired up with differential twisted pairs.
>
> I have the 24v dc power supply powering all the general clean power needs
> on the machine.  eg mesa 7i76 card and servo drives logic power.  also
> powering the servo on pin on the servo drive connector.
>
> I am still using the same powersupply I have always used.
>
> also the 5i25 is connected powering the 7i76 spindle encoder power which I
> am using (I don't have a external 5v powersupply.
>
> I checked the voltages between the 24v io and the 5v from 5i25 and they
> are within 1.5volts
>
> what would be the thing to test next?
>
> regards
>
> Andrew
>
> On Thu, May 21, 2020 at 1:03 PM andy pugh  wrote:
>
>> On Thu, 21 May 2020 at 01:47, andrew beck 
>> wrote:
>>
>> > Now all it seems to do is change from 0 to 1 on the count and there is
>> not
>> > any sense to the numbers changing.  it is not counting as it was before.
>>
>> This is what you see if one of the A or B channels has stopped
>> working. You can probably see this with halscope.
>>
>> What I suspect has happened is that you have added another DC source
>> to the mix with a different 0V reference, and that has exceeded the
>> common-mode limit of the encoder inputs (this only makes sense if your
>> encoder is wired as differential pairs. And jumpered accordingly)
>>
>> If your encoders are wired single-ended, then it's probably the same
>> root cause, and, in fact, it's easier to get this problem single-ended
>> (if you _can_ wire as different pairs, then you really should)
>>
>> If there are terms here that are unfamiliar I am happy to explain further.
>>
>> --
>> atp
>> "A motorcycle is a bicycle with a pandemonium attachment and is
>> designed for the especial use of mechanical geniuses, daredevils and
>> lunatics."
>> — George Fitch, Atlanta Constitution Newspaper, 1912
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>

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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

hey andy thanks for the quick reply.

I am wired up with differential twisted pairs.

I have the 24v dc power supply powering all the general clean power needs
on the machine.  eg mesa 7i76 card and servo drives logic power.  also
powering the servo on pin on the servo drive connector.

I am still using the same powersupply I have always used.

also the 5i25 is connected powering the 7i76 spindle encoder power which I
am using (I don't have a external 5v powersupply.

I checked the voltages between the 24v io and the 5v from 5i25 and they are
within 1.5volts

what would be the thing to test next?

regards

Andrew

On Thu, May 21, 2020 at 1:03 PM andy pugh  wrote:

> On Thu, 21 May 2020 at 01:47, andrew beck 
> wrote:
>
> > Now all it seems to do is change from 0 to 1 on the count and there is
> not
> > any sense to the numbers changing.  it is not counting as it was before.
>
> This is what you see if one of the A or B channels has stopped
> working. You can probably see this with halscope.
>
> What I suspect has happened is that you have added another DC source
> to the mix with a different 0V reference, and that has exceeded the
> common-mode limit of the encoder inputs (this only makes sense if your
> encoder is wired as differential pairs. And jumpered accordingly)
>
> If your encoders are wired single-ended, then it's probably the same
> root cause, and, in fact, it's easier to get this problem single-ended
> (if you _can_ wire as different pairs, then you really should)
>
> If there are terms here that are unfamiliar I am happy to explain further.
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andy pugh]

On Thu, 21 May 2020 at 01:47, andrew beck  wrote:

> Now all it seems to do is change from 0 to 1 on the count and there is not
> any sense to the numbers changing.  it is not counting as it was before.

This is what you see if one of the A or B channels has stopped
working. You can probably see this with halscope.

What I suspect has happened is that you have added another DC source
to the mix with a different 0V reference, and that has exceeded the
common-mode limit of the encoder inputs (this only makes sense if your
encoder is wired as differential pairs. And jumpered accordingly)

If your encoders are wired single-ended, then it's probably the same
root cause, and, in fact, it's easier to get this problem single-ended
(if you _can_ wire as different pairs, then you really should)

If there are terms here that are unfamiliar I am happy to explain further.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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