Re: [Emc-users] Grounding Issues

[Gregg Eshelman]

On 12/20/2015 4:06 PM, John Thornton wrote:
> Well it works fine till I plug in the VFD so I guess I'll have to rewire
> the machine and my shop again :(

VFD output directly to motor and adequate noise filtering upstream of 
the VFD?


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Re: [Emc-users] Grounding Issues

[Jon Elson]

On 12/20/2015 05:06 PM, John Thornton wrote:
> Well it works fine till I plug in the VFD so I guess I'll have to rewire
> the machine and my shop again :(
>
>
Well, that is now very important information!  Just plugging 
in the VFD, without having it start the spindle motor causes 
the problem? Then you are probably right.  If you only had 
problems when the spindle was running, then the line 
reactors might help.

I put a commercial line filter box on the VFD on my mill, I 
was having interference in a couple units, but only when the 
VFD was running the spindle.  The filter fixed it.

Jon

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Re: [Emc-users] Grounding Issues

[John Thornton]

Hi John,

You are correct I have a 220vac and a 120vac line coming into the 
machine. I didn't pull a 4 wire 220 line to those outlets in the shop so 
no neutral is there. If making a star ground doesn't fix the issue then 
I'll pull the 3 wire out and replace it with a 4 wire run. Not much fun 
but doable as I ran conduit up the wall to the attic.

Thanks for the great explanation, I'll save that and other things I've 
learned for future use.

JT

On 12/20/2015 2:25 PM, John Dammeyer wrote:
> Hi John,
>
> It sounds as if you have two AC lines coming into the machine.  One for the
> controller and one for the VFD.  The comments about a single star ground
> point are standard industry practice.  One breaker at the panel which
> protects the wire to the machine.  Another breaker inside the machine that
> protects the equipment.
>
> The Earth (green) comes in and is connected to a welded stud with a ring
> terminal, not a spade and double nutted so it can't possibly come loose.
> >From that point your controller and VFD are run.Never ever rely on the
> frame to carry the AC Ground (Earth) from one section to another.
>
> DC grounds are isolated from Earth Ground.  You can, connect the DC power
> supply minus to the Earth ground and it may even be a code requirement where
> you are.  Be aware, some PCs do this inside their power supply as do other
> types of COTS hardware.
>
> And here is the problem you have to watch out for.  Just because your DC
> volt meter reads continuity  (Zero Ohms)  between all the ground points
> doesn't mean that there is actually a path of lowest resistance following
> what you think it should.
>
> The moment you get into the switching power world which includes the VFD,
> Stepper Motors and Servos along with switching power supplies you get
> something called impedance.  That's based on the DC resistance (usually low)
> and a combination of the wire inductance and capacitance and frequency.
>
> Depending on how things are wired and routed the impedance of the return
> signal of the VFD may be lower through the RS232 (RS485) shield than it is
> through the green wire or even the shield around the power cable.  So just
> imagine the very noisy VFD signal returns through the communication shield
> because that has an impedance of 200 Ohms while the green wire has 1K.
> That's problem #1.
>
> There's two types of electrical noise.  Electrical coupling and magnetic
> coupling.  Electrical you shield against.  Usually with the shield tied to a
> common earth somewhere.
> Magnetic coupling is the same thing that makes a transformer or a motor
> function.  A rapidly changing magnetic field caused by rapidly changing
> current in a wire is coupled onto another wire that is in close proximity.
> Shielding doesn't protect against that. Twisted pairs do to a certain
> extent.
>
> The best protection is distance.  That's why you don't run the VFD power or
> Servo power tightly tie wrapped to the encoder signal.
>
> Therefore put the AC power side for the VFD on one side of the cabinet and
> run the control signals as far away as possible.
>
> There are lots of books written on this subject and probably as many
> opinions on what to do.  Ground shield at both ends.  Ground at one end.
> Don't ground.   Twist the wires.  Don't twist the wires.
>
> Start with the Star Grounding.  Make sure there aren't any DC paths that are
> unexpected as explained earlier.   Then start looking at how the noisy
> signals might find their way back through alternate paths.  Filters,
> Ferrites are all useful to block the signals.  Always best to block at the
> source.
>
> John
>
>
>
>
>
>
>> -Original Message-
>> From: John Thornton [mailto:j...@gnipsel.com]
>> Sent: December-20-15 10:27 AM
>> To: Enhanced Machine Controller (EMC)
>> Subject: Re: [Emc-users] Grounding Issues
>>
>>
>> I have a line reactor for the VFD but I've never hooked it up.
>>
>> http://www.automationdirect.com/adc/Shopping/Catalog/Drives/AC_Drive
>> _%28VFD%29_Spare_Parts_-a-_Accessories/AC_Line_Reactors/LR-23P0-1PH
>>
>> Speaking of VFD's mine is grounded to the breaker panel and not in the
>> machine anywhere. When I check from the ground terminal to the panel I
>> get 0 ohms so I assume that the back of the VFD is grounded to the
>> ground lug on the VFD.
>>
>> JT
>
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Re: [Emc-users] Grounding Issues

[Stephen Dubovsky]

Peter, this is the root cause in the change of behavior between <=2.6 and
2.7 w/ the 5i25+7i77 that a couple of us have been having (was discussed
here about a week ago)?  I have noticed an occasional warning in the prior
version I was running (just at startup iirc.)  I need to put some more
noise filters in, but my error is from the motor contactors pulling in when
I hit enable.  The original dc servo drives have big contactors that
disconnect the motor from the drive and put a braking resistor across it
when you disable them (or hit a limit switch, etc.)  Hitting the enable
(F2) causes those 3 big guys to pull in and reconnect the drives to the
motors.  That causes the sserial glitch and trips the contactors right back
off. I can't get past that step.  I haven't had time this week to play w/
the inc/dec parameters like Andy Pugh suggested.

Best,
Stephen

On Sun, Dec 20, 2015 at 1:34 PM, Peter C. Wallace  wrote:

>
> I looked into the 2.7 source and see that there is a problem with sserial
> error reporting that makes some single errors fatal (because the error
> reporting does not distinguish between per cycle error bits and sticky
> error
> status bits)
>
> That is errors that caused just a random popup on 2.6 will cause 2.7
> to shut down the sserial port (you still need a pretty bad noise spike to
> cause these errors but they should not be fatal)
>
>
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Re: [Emc-users] Grounding Issues

[John Dammeyer]

I used to have problems with one particular LED board I designed that would
reset or stop talking on IIC bus when I turned on my workbench circular
fluorescent light.  The type with the magnifying glass.  Turned out to be a
PC board layout problem and pull up resistors in the wrong place and the
wrong value.

Not an easy problem to solve when on a deadline.

Way back in the early nineties a stepper motor that adjusted the tool height
of a punch press by turning a ball screw would put noise onto the control
network.  It was worse during each punch cycle since the force on the press
would try and rotate the ball screw a tiny bit and the drive circuits became
noisier.   

The solution as simple but not applicable to CNC unfortunately.  The
engineers designed in a mechanical brake.  Once the tool was inserted and
the press closed to the calibrated position, the brake was enabled and the
stepper driver was disabled.  Noise gone.  Network better.

Moral of the story, always better to try and remove the noise from the
source rather than protect every device from it.

John Dammeyer



> -Original Message-
> From: Stephen Dubovsky [mailto:smdubov...@gmail.com]
> Sent: December-20-15 6:59 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Grounding Issues
> 
> 
> Peter, this is the root cause in the change of behavior between <=2.6 and
> 2.7 w/ the 5i25+7i77 that a couple of us have been having (was discussed
> here about a week ago)?  I have noticed an occasional warning in the prior
> version I was running (just at startup iirc.)  I need to put some more
> noise filters in, but my error is from the motor contactors pulling in
when
> I hit enable.  The original dc servo drives have big contactors that
> disconnect the motor from the drive and put a braking resistor across it
> when you disable them (or hit a limit switch, etc.)  Hitting the enable
> (F2) causes those 3 big guys to pull in and reconnect the drives to the
> motors.  That causes the sserial glitch and trips the contactors right
back
> off. I can't get past that step.  I haven't had time this week to play w/
> the inc/dec parameters like Andy Pugh suggested.
> 
> Best,
> Stephen
> 
> On Sun, Dec 20, 2015 at 1:34 PM, Peter C. Wallace 
> wrote:
> 
> >
> > I looked into the 2.7 source and see that there is a problem with
sserial
> > error reporting that makes some single errors fatal (because the error
> > reporting does not distinguish between per cycle error bits and sticky
> > error
> > status bits)
> >
> > That is errors that caused just a random popup on 2.6 will cause 2.7
> > to shut down the sserial port (you still need a pretty bad noise spike
to
> > cause these errors but they should not be fatal)
> >
> >
>

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Re: [Emc-users] Grounding Issues

[John Thornton]

I hope the procedure goes well.

Yes I have a scope.

JT

On 12/20/2015 1:23 PM, Gene Heskett wrote:
> But I am shortly going to be out of pocket till Monday afternoon. 
> Cataract fixings in the XYL's right eye are scheduled for first thing 
> in the morning, so we've reserved a room about a mile from the O.R. 
> Figures. :( Do you have an oscilloscope? Cheers, Gene Heskett 


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Re: [Emc-users] OT: Anyone have a small piece of 15/64" drill rod?

[Ken Strauss]

Have you considered that 15/64 is quite close to 6mm (~5.95mm)?

> -Original Message-
> From: Gregg Eshelman [mailto:g_ala...@yahoo.com]
> Sent: Sunday, December 20, 2015 6:19 PM
> To: Enhanced Machine Controller (EMC)
> Subject: [Emc-users] OT: Anyone have a small piece of 15/64" drill rod?
>
> I need a small chunk of 15/64" drill rod, about 4 to 6" long. Nobody
within 100
> miles stocks drill rod, or not in "oddball" 64th sizes. I don't need 3
feet of it
> either, like I'd have to get from online stores.
>
> I could get a long shank drill bit and cut it off that, but single bits in
"odd" sizes
> are as commonly available nearby as the rod. :P
>
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[Emc-users] OT: Anyone have a small piece of 15/64" drill rod?

[Gregg Eshelman]

I need a small chunk of 15/64" drill rod, about 4 to 6" long. Nobody 
within 100 miles stocks drill rod, or not in "oddball" 64th sizes. I 
don't need 3 feet of it either, like I'd have to get from online stores.

I could get a long shank drill bit and cut it off that, but single bits 
in "odd" sizes are as commonly available nearby as the rod. :P

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Re: [Emc-users] Grounding Issues

[John Thornton]

An update, I made a star grounding configuration so EVERY ground comes 
from the same place. I tested with the VFD unplugged and all is fine, 
plug the VFD in and same problem sserial errors. The VFD is 220v so to 
use one power source I'd have to run new wire from the panel to the 220v 
outlet and get a 4 wire plug. Not impossible but a PIA to work up in the 
attic

JT

On 12/20/2015 7:20 AM, John Thornton wrote:
> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
> all the Anilam controls a while back. I've retained the drives and power
> supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>   From the get go I've had problems with the electronics on this machine.
> The VFD is controlled by modbus via the gs2 component. The VFD gets
> reset to default parameters all the time from noise on the modbus. the
> 5i25 get sserial errors. The sserial errors are so bad now it won't even
> move an axis. The spindle works ok. The power supply is a simple bridge
> rectifier with a huge blue cap and a large power resistor across the cap.
>
> Peter keeps telling me it's a grounding issue so where do I start
> looking and what do I need to do?
>
> Thanks
> JT
>
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Re: [Emc-users] Grounding Issues

[John Dammeyer]

John
You're welcome.
My  _Go_To_  book is "Electromagnetic Compatibility Engineering" By Henry
W.Ott.  Published by WILEY.
http://ca.wiley.com/WileyCDA/WileyTitle/productCd-0470189304.html
I've retained perhaps 5% and for a while the book went everywhere with me as
I tried to absorb the details.  
It's not black magic although it appears that way sometimes.
John Dammeyer


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Re: [Emc-users] OT: Anyone have a small piece of 15/64" drill rod?

[Gregg Eshelman]

On 12/20/2015 5:39 PM, Ken Strauss wrote:
> Have you considered that 15/64 is quite close to 6mm (~5.95mm)?

Yes, but the hole this has to fit is 15/64" and a 15/64" drill shank is 
as perfect a fit as can be without being a press fit so I don't need to 
mess that up.


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Re: [Emc-users] Grounding Issues

[John Thornton]

Well it works fine till I plug in the VFD so I guess I'll have to rewire 
the machine and my shop again :(

JT

On 12/20/2015 2:25 PM, John Dammeyer wrote:
> Hi John,
>
> It sounds as if you have two AC lines coming into the machine.  One for the
> controller and one for the VFD.  The comments about a single star ground
> point are standard industry practice.  One breaker at the panel which
> protects the wire to the machine.  Another breaker inside the machine that
> protects the equipment.
>
>


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Re: [Emc-users] Grounding Issues

[TJoseph Powderly]

if you can get a scope (2 trace)
and _SEE_ the noise
from your machine ground to a good ground,
then you can see when you make a difference.

a good ground can be tested with a megger ( hard to find)
a good ground can be a copper rod driven 10 ft into good earth
so find the best you can and look to see if theres a difference.

a scope is a very visual thing, forget the scales for now, the picture 
is more important.

my 2c ( hmm 2b here )
tomp tjtr33

On 12/20/2015 07:20 AM, John Thornton wrote:
> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
> all the Anilam controls a while back. I've retained the drives and power
> supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>   From the get go I've had problems with the electronics on this machine.
> The VFD is controlled by modbus via the gs2 component. The VFD gets
> reset to default parameters all the time from noise on the modbus. the
> 5i25 get sserial errors. The sserial errors are so bad now it won't even
> move an axis. The spindle works ok. The power supply is a simple bridge
> rectifier with a huge blue cap and a large power resistor across the cap.
>
> Peter keeps telling me it's a grounding issue so where do I start
> looking and what do I need to do?
>
> Thanks
> JT
>
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Re: [Emc-users] Grounding Issues

[John Dammeyer]

Don't get too carried away with Earth as the most important part of
grounding.  After all those big metal tubes that fly through the sky aren't
connected to ground and they have all sorts of power systems from DC to AC
(if you can afford business class).

The point is to make sure that the current that leaves from one location
ends up back there since current only flows when there's a complete circuit.


John


> -Original Message-
> From: TJoseph Powderly [mailto:tjt...@gmail.com]
> Sent: December-20-15 4:17 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Grounding Issues
> 
> 
> if you can get a scope (2 trace)
> and _SEE_ the noise
> from your machine ground to a good ground,
> then you can see when you make a difference.
> 
> a good ground can be tested with a megger ( hard to find)
> a good ground can be a copper rod driven 10 ft into good earth
> so find the best you can and look to see if theres a difference.
> 
> a scope is a very visual thing, forget the scales for now, the picture
> is more important.
> 
> my 2c ( hmm 2b here )
> tomp tjtr33
> 
> On 12/20/2015 07:20 AM, John Thornton wrote:
> > I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
> > all the Anilam controls a while back. I've retained the drives and power
> > supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
> >   From the get go I've had problems with the electronics on this
machine.
> > The VFD is controlled by modbus via the gs2 component. The VFD gets
> > reset to default parameters all the time from noise on the modbus. the
> > 5i25 get sserial errors. The sserial errors are so bad now it won't even
> > move an axis. The spindle works ok. The power supply is a simple bridge
> > rectifier with a huge blue cap and a large power resistor across the
cap.
> >
> > Peter keeps telling me it's a grounding issue so where do I start
> > looking and what do I need to do?
> >
> > Thanks
> > JT
> >
> >

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> 
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Re: [Emc-users] Grounding Issues

[John Dammeyer]

John,
I'd still take a close look at your existing system to see if it is robust.

Perhaps an example from a different project my give you an idea.  Bear with
me.  The story is kind of long.

I designed an LED lighting system that ran of a 48V bank of batteries
charged by generator.  

Charging could  raise the voltage as high as 56 volts.  The voltage
regulators on each LED lamp was good to 70V so I had plenty of leeway, or so
I thought.  The power distribution system was in the centre of a long barge.
The genset and batteries at one end.  The first time we powered up the
system and flashed the lights on and off a few times something odd happened.
The lights went a funny colour and then many of them went off.

Since I'd already built one system that ran on 24V and had been operational
for 8 months we were perplexed.  True, this one had different boards with
48V instead of 24V.  On the way back out we were discussing what could have
damaged so many lights.The Chief Engineer asked if the coil of wire
would have any impact.  I asked what coil.

Well it turns out the wire running the DC from the battery pack and the
control panel was very expensive.  So to avoid cutting out a section that
would end up useless they coiled it under the cabinet.A change from 70A
to about 10A was much like an ignition coil when the points open.  The
inductive kick was probably well over 100V especially since the generator
was running at the time.

We cut the cable to the exact length needed.  It still ran in a metal trough
under steel plates on the barge deck but looking at the power with a scope
showed the problem had gone away.  One wouldn't think a coil of about 5
turns would make a difference but it did.

The second issue that was prevalent on both systems was that each string of
lamps was up to 35m long with a restriction of 8A current on the power
conductors.  The lamps were all in the last 10m so there was 25m worth of
feed cable.   That means at full lights on the first lamp after the 20m had
the highest voltage and the last lamp 10m further down had the least voltage
due to the multiple voltage drops as each lamp used power.

I'll introduce another term here.  It's called common mode voltage.  The
power through the 24V or 48V connection to the lamps has a voltage drop
based on current consumption.  There's an identical drop across the ground
power wire.  The one on the 24V line isn't that important as long as it can
still run the load. 

But the voltage drop across the ground lead means the local lamps see a
different potential between ground and the communications bus than at the
other end of the 35m cable.  Most communications chips have a specification
called maximum common mode voltage.That essentially means you can't have
more of a difference between the grounds when the signal is also part of the
connection.  

So for example if the common mode is a 6V drop across the ground conductor
then the voltage at one end between tx and gnd might be 2.5V.  At the lamp
at the other end the signal is also 2.5V since the lamps sees the local
ground.   But that 6V shows up as soon as there's enough current on the
ground to cause the 6V drop.  Now one end sees 8.5V relative to ground.
This is static and measurable with a simple meter.

OK back to CNC.

This is the biggest reason you run 4 servo or stepper motor drives with the
power and as a single point on the power supply rather than ground to ground
to ground to ground.  If each Servo draws 8A and the last one sees the
ground shift up because of voltage drops along the ground bus and the
signals to the motors (or encoder feedback) may be compromised.

Now let's look at the AC side of things.  You run all your power to  a
single point doing it right. 

Each wire to each driver has inductance.  And there's capacitance between
the wire and the cabinet.  At the right frequencies the noise ground return
path is now through the capacitance to the cabinet rather than along the
wire.  

Since each driver and each wire is further away from the power supply we're
back to the daisy chained power distribution system with more common mode
voltage at the far end higher than at the end close to the power.  And again
that can affect the encoder or control signals.  But now it's sporadic.
Hard to track.  Stepper winding current collapsing creating noise spikes at
the same instant as a message to a VFD.

So shielding power cabling to your devices with the shield terminated at the
distribution end and open at the other can suppress those kinds of problems.
Now the high frequency signals and noise are brought back to where you want.

Does that all make sense?

John Dammeyer







> -Original Message-
> From: John Thornton [mailto:j...@gnipsel.com]
> Sent: December-20-15 3:06 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Grounding Issues
> 
> 
> Well it works fine till I plug in the VFD so I guess I'll have to rewire
> the machine and my shop again :(

Re: [Emc-users] Grounding Issues

[Bertho Stultiens]

On 12/21/2015 12:59 AM, John Thornton wrote:
> An update, I made a star grounding configuration so EVERY ground comes 
> from the same place. I tested with the VFD unplugged and all is fine, 
> plug the VFD in and same problem sserial errors. The VFD is 220v so to 
> use one power source I'd have to run new wire from the panel to the 220v 
> outlet and get a 4 wire plug. Not impossible but a PIA to work up in the 
> attic

If you have a dual supply and a transformer for AC 110V -> 220V (or the
other way around), then you may need to reverse the polarity of phase
and neutral of the transformer.

You may see common-mode injection because the phase-polarity of the two
supplies are 180 degrees out of sync. The chassis will then be
conducting the capacitively coupled common-mode, which may interfere a lot.


-- 
Greetings Bertho

(disclaimers are disclaimed)

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Re: [Emc-users] Grounding Issues

[R.L. Wurdack]

Some of them tubes are Carbon fiber composite these days. Makes grounding 
more fun.


- Original Message - 
From: "John Dammeyer" 
To: "'Enhanced Machine Controller (EMC)'" 
Sent: Sunday, December 20, 2015 4:59 PM
Subject: Re: [Emc-users] Grounding Issues


> Don't get too carried away with Earth as the most important part of
> grounding.  After all those big metal tubes that fly through the sky 
> aren't
> connected to ground and they have all sorts of power systems from DC to AC
> (if you can afford business class).
>
> The point is to make sure that the current that leaves from one location
> ends up back there since current only flows when there's a complete 
> circuit.
>
>
> John
>
>
>> -Original Message-
>> From: TJoseph Powderly [mailto:tjt...@gmail.com]
>> Sent: December-20-15 4:17 PM
>> To: Enhanced Machine Controller (EMC)
>> Subject: Re: [Emc-users] Grounding Issues
>>
>>
>> if you can get a scope (2 trace)
>> and _SEE_ the noise
>> from your machine ground to a good ground,
>> then you can see when you make a difference.
>>
>> a good ground can be tested with a megger ( hard to find)
>> a good ground can be a copper rod driven 10 ft into good earth
>> so find the best you can and look to see if theres a difference.
>>
>> a scope is a very visual thing, forget the scales for now, the picture
>> is more important.
>>
>> my 2c ( hmm 2b here )
>> tomp tjtr33
>>
>> On 12/20/2015 07:20 AM, John Thornton wrote:
>> > I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
>> > all the Anilam controls a while back. I've retained the drives and 
>> > power
>> > supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>> >   From the get go I've had problems with the electronics on this
> machine.
>> > The VFD is controlled by modbus via the gs2 component. The VFD gets
>> > reset to default parameters all the time from noise on the modbus. the
>> > 5i25 get sserial errors. The sserial errors are so bad now it won't 
>> > even
>> > move an axis. The spindle works ok. The power supply is a simple bridge
>> > rectifier with a huge blue cap and a large power resistor across the
> cap.
>> >
>> > Peter keeps telling me it's a grounding issue so where do I start
>> > looking and what do I need to do?
>> >
>> > Thanks
>> > JT
>> >
>> >
> 
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>>
>>
>>
> 
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> 



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Re: [Emc-users] Grounding Issues

[Peter C. Wallace]

On Sun, 20 Dec 2015, Stephen Dubovsky wrote:

> Date: Sun, 20 Dec 2015 21:59:26 -0500
> From: Stephen Dubovsky 
> Reply-To: "Enhanced Machine Controller (EMC)"
> 
> To: "Enhanced Machine Controller (EMC)" 
> Subject: Re: [Emc-users] Grounding Issues
> 
> Peter, this is the root cause in the change of behavior between <=2.6 and
> 2.7 w/ the 5i25+7i77 that a couple of us have been having (was discussed
> here about a week ago)?  I have noticed an occasional warning in the prior
> version I was running (just at startup iirc.)  I need to put some more
> noise filters in, but my error is from the motor contactors pulling in when
> I hit enable.  The original dc servo drives have big contactors that
> disconnect the motor from the drive and put a braking resistor across it
> when you disable them (or hit a limit switch, etc.)  Hitting the enable
> (F2) causes those 3 big guys to pull in and reconnect the drives to the
> motors.  That causes the sserial glitch and trips the contactors right back
> off. I can't get past that step.  I haven't had time this week to play w/
> the inc/dec parameters like Andy Pugh suggested.
>
> Best,
> Stephen


Yes I'm pretty sure this is the issue. Error reporting was improved in 2.7
but the error reporting of sticky error bits needs to be conditional on per 
cycle general (new) error flags and its not.

I will try and get this fixed ASAP

Also there is a small chance that updating the 5I25 sserial firmware from 
pre-35 versions to the current version 43 makes the RX UART a bit more
sensitive to input noise as the internal processor and UART clock are
changed from 33 MHz to 100 MHz.

I do have a fix for this ( a 1/2 bit time digital filter on the RX 
UART input ) and will add this to all bitfiles containing sserial firmware
but currently I have new bitfiles for the 5I25/6I25 and 7I76 and 7I77 here:

http://freeby.mesanet.com/filtered.zip


>
> On Sun, Dec 20, 2015 at 1:34 PM, Peter C. Wallace  wrote:
>
>>
>> I looked into the 2.7 source and see that there is a problem with sserial
>> error reporting that makes some single errors fatal (because the error
>> reporting does not distinguish between per cycle error bits and sticky
>> error
>> status bits)
>>
>> That is errors that caused just a random popup on 2.6 will cause 2.7
>> to shut down the sserial port (you still need a pretty bad noise spike to
>> cause these errors but they should not be fatal)
>>
>>
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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] Grounding Issues

[tom-emc]

There was a thread back in May (11-15) of 2015 Subject was "If there's one 
thing I hate, all the noise, noise, noise, noise” where I was having strange 
noise issues.  There are a lot of helpful suggestions there for tracking down 
noise.  In my case the problem was an overly sensitive keyboard, but before I 
narrowed that down I spent quite a bit of time tracing down grounds and also 
adding both an input power filter (ebay search "Rasmi Filter" for inexpensive 
options) for the VFD and also adding 4 Ferrites to the output VFD power leads 
to the motor.  These are the ferrites I used: 
https://www.digikey.com/product-detail/en/74277290/732-3092-ND/2626031

Good luck.
-Tom

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Re: [Emc-users] [was] Anybody know where to find a pdf on the HOYMK SSR40DA SSR?

[John Kasunich]

On Sun, Dec 20, 2015, at 03:45 PM, Gene Heskett wrote:
> On Sunday 20 December 2015 04:27:39 Gene Heskett wrote:
> 
> [... back to readable size, on my charge-pump detection to run the SSR's]
> 
> > Has anyone else concocted such a circuit, and were you able to get
> > enough pump power out of it running the BoB on 5 volts, with the pump
> > at 500 hz, to run an SSR without resorting to an external current
> > booster?
> 
> Now I am both bumfuzzled and confused. There really ought to be a formula 
> for calculating the size of the capacitors needed, but there is 
> absolutely zip in ITT #5, nor in the hambook of about the same vintage. 
> 
> So, I guess its build it, and test it by the old fashioned cuss & cry 
> method. Seems to me there really ought to be, in the year 2015, a plug 
> in the blanks formula for that.  Sigh...
> 

My gut feeling is that you won't be able to do it.

First, lets make sure we are talking about the same circuit.  A google image
search found this schematic of a charge pump, which is the circuit I normally
use.
http://www.zen22142.zen.co.uk/Theory/diode_pump/Image152.jpg
(refer to the circuit on the left)

Assume that the input is swinging from 0.0 to 5.0 volts.  Also assume that
the loading is negligible.  When the input is low, the voltage on the left side
of Cp is 0.0, and the right side is -0.7V due to the drop in D1.  When the input
goes high, the left side of Cp is 5.0V, and the right side is 4.3V, assuming 
zero change in the voltage across Cp.  Because of the drop across D2, the
output is 4.3-0.7 = 3.6V.  Pretty marginal.  And that is with zero load, and 
an output that swings a full 5V.  No real output will swing all the way down
to 0.0 or up to 5.0V, so you lose another couple tenths of a volt.

The above assumes that there is NO CHANGE in the voltage across Cp.
That means no current flows into or out of Cp, and the circuit delivers 
no output current (I said "assume loading is negligable").

To deliver any load current, the voltage across Cp has to change, and that
will further drop the output voltage.  Say you need a load current of 10mA.
That is 10 milli-coulombs per second.  If the input frequency is 500Hz, then
each cycle needs to deliver 0.010/500 = 20 micro-coulombs.  If you need
an output voltage of 3V, and the ideal no-load output is 3.6V, then the voltage 
across Cp can only be allowed to drop 0.6V when 20 micro-coulombs of
charge is extracted from it.  C = Q/V = 0.20 / 0.6 = 33uF.  That is a
HUGE pump cap, and will badly load down whatever is driving it.

When I make a charge pump, I usually think of something like Cr = 0.1uF,
and Cp = 0.01uF.  Charge per cycle at 0.6V droop is 0.006 micro-coulombs,
and I run it at 10kHz instead of 500Hz, for a total load current of 60 micro-
amps.  Put a 100K load resistor as a load and drive the gate of a logic 
level MOSFET and it works fine.  But getting milli-amp currents out of a
low-powered charge pump is much much harder.

John Kasunich





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Re: [Emc-users] Grounding Issues

[John Thornton]

I have a line reactor for the VFD but I've never hooked it up.

http://www.automationdirect.com/adc/Shopping/Catalog/Drives/AC_Drive_%28VFD%29_Spare_Parts_-a-_Accessories/AC_Line_Reactors/LR-23P0-1PH

Speaking of VFD's mine is grounded to the breaker panel and not in the 
machine anywhere. When I check from the ground terminal to the panel I 
get 0 ohms so I assume that the back of the VFD is grounded to the 
ground lug on the VFD.

JT

On 12/20/2015 11:44 AM, Kirk Wallace wrote:
> On 12/20/2015 05:20 AM, John Thornton wrote:
>> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
>> all the Anilam controls a while back. I've retained the drives and power
>> supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>>From the get go I've had problems with the electronics on this machine.
> I have had good results (noise on encoder lines) by adding mains filters
> to my VFD power inputs.
>
> The shiny box here:
> http://www.wallacecompany.com/cnc_lathe/HNC/00024-1a.jpg
>
> I suspect any switching power circuit might benefit from installing an
> input filter.
>


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Re: [Emc-users] Grounding Issues

[John Thornton]

The bpel04 has a star washer and the stud is welded to the back plane. 
The cases are bolted tight to the main column. The DIN rail is fastened 
down with star washers and the locking screws are tight.

JT

On 12/20/2015 11:42 AM, Dave Caroline wrote:
> The din rail in the 05 pic is that real tight to the back panel (add
> star washers to cut through paint), make sure the green/yellow blocks
> have the middle screw tight.
>
> One mighty thin grounding wire in bpel04.jpg, also could add star
> washer to cut through paint
>
> You could measure the ground resistance too if you can.
>
> Others are likely to mention you have two grounds rather than a star
> ground. Make sure cases are tight to frame to guarantee continuity
>
> Dave Caroline
>
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Re: [Emc-users] Grounding Issues

[Peter C. Wallace]

On Sun, 20 Dec 2015, John Thornton wrote:

> Date: Sun, 20 Dec 2015 12:26:51 -0600
> From: John Thornton 
> Reply-To: "Enhanced Machine Controller (EMC)"
> 
> To: "Enhanced Machine Controller (EMC)" 
> Subject: Re: [Emc-users] Grounding Issues
> 
> I have a line reactor for the VFD but I've never hooked it up.
>
> http://www.automationdirect.com/adc/Shopping/Catalog/Drives/AC_Drive_%28VFD%29_Spare_Parts_-a-_Accessories/AC_Line_Reactors/LR-23P0-1PH
>
> Speaking of VFD's mine is grounded to the breaker panel and not in the
> machine anywhere. When I check from the ground terminal to the panel I
> get 0 ohms so I assume that the back of the VFD is grounded to the
> ground lug on the VFD.
>
> JT

I looked into the 2.7 source and see that there is a problem with sserial 
error reporting that makes some single errors fatal (because the error 
reporting does not distinguish between per cycle error bits and sticky error 
status bits)

That is errors that caused just a random popup on 2.6 will cause 2.7
to shut down the sserial port (you still need a pretty bad noise spike to 
cause these errors but they should not be fatal)


Peter Wallace

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Re: [Emc-users] Grounding Issues

[John Thornton]

On 12/20/2015 11:47 AM, Gene Heskett wrote:
> On Sunday 20 December 2015 12:15:21 John Thornton wrote:
>
>> Back from shopping...
>>
>> Pencil sketch of the power side
>> http://gnipsel.com/images/bp-knee-mill/bpel03.in
> the left box probably needs the paint cleaned off under it, and maybe a
> star washer under the spade lug for extra connection bite. And there
> ought to be a similar ground to the box in the right box. But as sub
> boxes generally have isolated busses for the static (bare wires in the
> romex */3 wires) in order to bot short circuit the connection at the
> main entrance a foot or so from the meterhead.
>
>> Incoming terminal block on left panel where extra ground is
>> http://gnipsel.com/images/bp-knee-mill/bpel04.jpg
> Here I cannot see the above green wire, the static, while connected to
> the  to the box, but it does not leave to connect the rest of the stuff,
> just the white (neutral) and black (127 hot) wires leaving are all I see
> leaving. Tieing to the box, is to ground the box to the static
> grounding.
>
>> next terminal block on right panel
>> http://gnipsel.com/images/bp-knee-mill/bpel05.jpg
>>
> And here, unless its in the block mounting for the two green wires I can
> see, and I am not at all familiar with that style of terminal block,
> they are floating.  Are the two pieces of SJ I see coming in at the top,
> source or load?

The green/yellow terminal blocks are standard ground blocks, the center 
screw tightens a gripper that forces a tight metal to metal contact with 
the DIN rail and the terminals. It's very much grounded to the DIN rail 
and the DIN rail is fastened to the back plane with welded on studs and 
star washers and nuts.

http://www.automationdirect.com/adc/Shopping/Catalog/Terminal_Blocks/DINnector_DIN-Rail_Terminal_Blocks/Ground_Terminal_Blocks/DN-G10

They are very expensive...
> Offhand, it does tend to look like a noise factory from here. :(  Those
> green wires should come from the real ground at the service entrance and
> go all the way to that single point bolt in the driver cabinet wall,
> then from there to everything else as a star ground.
>
>> JT
>>
>> On 12/20/2015 8:37 AM, Gene Heskett wrote:
>>> On Sunday 20 December 2015 08:20:38 John Thornton wrote:
 I have a BP knee mill with an Anilam 1100M CNC kit on it. I've
 removed all the Anilam controls a while back. I've retained the
 drives and power supply and added a GS2 VFD for the spindle. I have
 a 5i25 7i77 setup. From the get go I've had problems with the
 electronics on this machine. The VFD is controlled by modbus via
 the gs2 component. The VFD gets reset to default parameters all the
 time from noise on the modbus. the 5i25 get sserial errors. The
 sserial errors are so bad now it won't even move an axis. The
 spindle works ok. The power supply is a simple bridge rectifier
 with a huge blue cap and a large power resistor across the cap.

 Peter keeps telling me it's a grounding issue so where do I start
 looking and what do I need to do?

 Thanks
 JT
>>> Start with a roll of flat braid equ to a 8 or 10 gauge wire.
>>> Establish a bolt to the case of the controller as a master ground,
>>> and make sure everything that references ground in the controller
>>> box is grounded at this bolt.
>>>
>>> Tie this bolt to the buildings static ground using that pin of the
>>> controllers power cable, BUT not to the building supply neutral as
>>> thats usually noisy as can be.  Or to a real ground rod but that may
>>> have a considerable damaging joltage on it when there is lightning
>>> nearby so is both against the NEC and would be poor practice.
>>>
>>> Then extend that ground, using this braid, to the bridgeports main
>>> casting, and perhaps also to the table and knee as the lube oil in
>>> the ways might preclude a really good ground on the table without
>>> it.
>>>
>>> Extend that ground from that bolt to the computers case if it is
>>> separated from the controller box.
>>>
>>> This is called a star ground system, where everything is common at
>>> this bolt.  If you can disconnect each wire from that bolt, and
>>> still measure continuity of 200 ohms or less from the bolt to the
>>> disconnected wire, then that wire has an unwanted ground somewhere,
>>> run it down and remove it, you want that to be "grounded" only at
>>> that bolt.
>>>
>>> The idea is that even if it does bounce a bit from a nearby
>>> lightning strike, it all bounces in unison with no big voltage drops
>>> between anything that can damage it, or induce noise that would be
>>> miss-detected as a signal.
>>>
>>> Years ago when I was screwing with vz & their bad copper, I figured
>>> on losing a modem everytime I heard thunder. Getting PO'd, I first
>>> opened up the wall a bit, pulled out the duplex that was going to
>>> power what I had in mind, and soldered all the connections in that
>>> box. Then I bought the biggest surge arrestor I could find, one that

Re: [Emc-users] Anybody know where to find a pdf on the HOYMK SSR40DA SSR?

[Gene Heskett]

On Saturday 19 December 2015 19:46:23 Gene Heskett wrote:

> On Saturday 19 December 2015 18:34:23 Gene Heskett wrote:
> > On Saturday 19 December 2015 18:07:58 Gene Heskett wrote:
> > > My google-fu seems unusable for this.
> > >
> > > The SSR's arrived this afternoon, and I need to figure out what
> > > sort of an R to use as buildout as I think I will enable it with
> > > the same 0-12 volt signal that enables the pwm servo amplifier I
> > > am using to drive the spindle.
> > >
> > > They are rated 3-32 volts in, and <10 ma to fire. But I've no real
> > > data on the opto from sparkfun that I am using to drive the pwm
> > > servo's 12 volt enable. I've no clue how many mills it can
> > > actually source.
> > >
> > > I will go see how many it can spare with a 1k load resistor
> > > though.
> >
> > That turns out to be around 10.4 mills, but my testing found another
> > problem with that idea, so apparently I must use a 2nd one, and find
> > a pin to drive it, such that the power input is switched by the
> > presence or lack thereof, of a charge pump signal at 500 hz from
> > LCNC. Why? powered up, but LCNC is not running, the default outputs
> > of the 5i25 are a logic one. So that enables the servo amp (and this
> > SSR) even if it has no controlling signal, which in turn defeats the
> > soft-start. And I've no clue 5 months later, if I have a spare pin
> > on the first BoB. I do not believe I do without ripping out my
> > ability to drive an A/B/C 4th axis.
> >
> > Fun & games, including finding a mounting place for both of them.
>
> That I found, on the outside of the box unforch.  Might be advisable
> to make a cover just to keep the NEC happy.  At some point an
> indeterminant time in the future.  Its up on a high shelf I have to
> climb a small ladder or tall stepstool to access it.
>
> No pins left on P3 of the 5i25 though as I had set it up originally
> for an A axis, but because of driver space in the box, will have to be
> considered as a package in a separate driver box if and when I need it
> but it will be up to PCW to tell me how to load 4 stepgens when one of
> them is going to be driving P2.  So pins 8-9 are now free to be used
> for these 2 functions as I have now commented out any references to
> the A axis in both the .ini and .hal files. But again, because the
> LCNC off is a logic high, I will build the charge pump detectors to
> drive the - terminal of the SSR.  With enough filter to prevent the
> powerup-powerdown 1 or 3 cycle triggers associated with turning it on
> or off from the power switch.
[...]
Charge pump continued;

I found a pdf, on a different brand of SSR that carries the same SSR-40DA 
designation.

>From that on=>2.4 volts, off = <1.0 volt, but on the next line it says 
the trigger current 7.5 mills/12 volts. So I am somewhat confused.
The BoB can only swing 5 volts, and its current delivery into the usual 
voltage doubler, 2 diode, 2 capacitor circuit would be limited by what 
it can deliver as pullup. At 500 hz, the pump capacitor should be 
perhaps 10% that of the output capacitor, which for power up surges 
should be directly across the input to the SSR. But my choices there are 
limited by my lack of a decent assortment of tantalum caps. 
Electrolitics are out because of the low voltages involved since they 
will deform and lose capacitance in just a couple years.

Now, I know the T=RC enters into this, and that T is a millisecond up and 
a millisecond down. So that would seem, since R is in owms and C is in 
farads, that its going to take some multi-microfarad caps to make this 
work at the leasurely charge pump frequency available when there is 
no "base thread".

I've found some assortments, one even coming with a carry box with 18 
drawers and 5 of each value starting with 1 u-f, and am considering 
buying such a kit.

See figure 7 at 
but with the diodes reversed in order to drive the - terminal of the SSR. 
+ terminal will be grounded, and the left hand current source connected 
there also. By that means I hope to prevent the mains switch power 
on/off's from falsly triggering it.

I am using a similar circuit, with smaller electrolitic caps that I know 
will fail eventually, driving a scrap bin to-220 transistor which drives 
a 24 volt P to switch the vacuum cleaner. This power on surge as the 5 
volts come up on the BoB is strong enough that it gets about a .2 second 
power on when the mains is turned on.  Causes a noisy growl as it winds 
back down.  Poor choice of caps coupled with excessive gain in the 
to-220.

Has anyone else concocted such a circuit, and were you able to get enough 
pump power out of it running the BoB on 5 volts, with the pump at 500 
hz, to run an SSR without resorting to an external current booster?

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)
Some mill pix are 

[Emc-users] Grounding Issues

[John Thornton]

I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed 
all the Anilam controls a while back. I've retained the drives and power 
supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup. 
 From the get go I've had problems with the electronics on this machine. 
The VFD is controlled by modbus via the gs2 component. The VFD gets 
reset to default parameters all the time from noise on the modbus. the 
5i25 get sserial errors. The sserial errors are so bad now it won't even 
move an axis. The spindle works ok. The power supply is a simple bridge 
rectifier with a huge blue cap and a large power resistor across the cap.

Peter keeps telling me it's a grounding issue so where do I start 
looking and what do I need to do?

Thanks
JT

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Re: [Emc-users] Grounding Issues

[Gene Heskett]

On Sunday 20 December 2015 08:20:38 John Thornton wrote:

> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
> all the Anilam controls a while back. I've retained the drives and
> power supply and added a GS2 VFD for the spindle. I have a 5i25 7i77
> setup. From the get go I've had problems with the electronics on this
> machine. The VFD is controlled by modbus via the gs2 component. The
> VFD gets reset to default parameters all the time from noise on the
> modbus. the 5i25 get sserial errors. The sserial errors are so bad now
> it won't even move an axis. The spindle works ok. The power supply is
> a simple bridge rectifier with a huge blue cap and a large power
> resistor across the cap.
>
> Peter keeps telling me it's a grounding issue so where do I start
> looking and what do I need to do?
>
> Thanks
> JT
>
Start with a roll of flat braid equ to a 8 or 10 gauge wire. Establish a 
bolt to the case of the controller as a master ground, and make sure 
everything that references ground in the controller box is grounded at 
this bolt. 

Tie this bolt to the buildings static ground using that pin of the 
controllers power cable, BUT not to the building supply neutral as thats 
usually noisy as can be.  Or to a real ground rod but that may have a 
considerable damaging joltage on it when there is lightning nearby so is 
both against the NEC and would be poor practice.

Then extend that ground, using this braid, to the bridgeports main 
casting, and perhaps also to the table and knee as the lube oil in the 
ways might preclude a really good ground on the table without it.  

Extend that ground from that bolt to the computers case if it is 
separated from the controller box.

This is called a star ground system, where everything is common at this 
bolt.  If you can disconnect each wire from that bolt, and still measure 
continuity of 200 ohms or less from the bolt to the disconnected wire, 
then that wire has an unwanted ground somewhere, run it down and remove 
it, you want that to be "grounded" only at that bolt.

The idea is that even if it does bounce a bit from a nearby lightning 
strike, it all bounces in unison with no big voltage drops between 
anything that can damage it, or induce noise that would be miss-detected 
as a signal.

Years ago when I was screwing with vz & their bad copper, I figured on 
losing a modem everytime I heard thunder. Getting PO'd, I first opened 
up the wall a bit, pulled out the duplex that was going to power what I 
had in mind, and soldered all the connections in that box. Then I bought 
the biggest surge arrestor I could find, one that had phone line & cable 
tv arrestors in it.  And I bought the biggest home UPS I could find. 
Everything in this room but the lights is plugged in either to that UPS 
or that surge arrestor, and both are plugged into this all soldered 
duplex. Now lightning can hit the pole my transformer is on, possibly 
bouncing everything in this room by 100 kilovolts, but it all bounces in 
unison and I haven't lost a modem or anything else that I could 
associate the loss with local lightning strikes. But since I did get, 
from a wired keyboard I was typing on at the time, a really good jolt 
thru my fingers like shuffling ones feet on the rug and then grabbing 
the doorknob, but it didn't hurt the computer or the keyboard, but I now 
use wireless keyboard and mice.

If the frame of the bridgeport is grounded thru other means, such as a 
3rd pin on a power cable, this should be defeated in order to remove the 
potential ground loop which can be a source of quite a bit of induced 
noise.

Motor drive, and feedback cables from the motors should be shielded, with 
the shields cut off at the motor ends of the cable but tied to this bolt 
at the controller end, thereby interrupting that potential ground loop.

The general idea is to have one common "ground" point, even if its is not 
an earthen ground. That s/b, by the NEC, at the service entrance, a 
minimum of two full rods driven 6 feet apart, with an 8 gauge wire 
bonding them to the buildings static ground for the 3rd pin of all the 
duplexes and neutral from the pole drop, the only place it is legal to 
interconnect them.  Hanging an amprobe on any of the bare static wires 
in the service box should get you a zero reading regardless of what is 
powered up.  If you do see a reading, something out on that circuit is 
miss-wired. Fix it. Its just good practice.

It and I, may sound arbitrary John, but it works.  And its NEC legal.
If you have a decent scope, just waving a probe around with the gain 
turned up near suspected noise sources can be very educational.

I've had to follow too many electricians around, fixing their mix-n-match 
attitude about static and neutral being the same thing, way too many 
times.

Let us know what you did find when you've cleaned up the problem, please.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, 

Re: [Emc-users] Grounding Issues

[John Thornton]

Ok, I'll work on that this morning.

Thanks
JT

On 12/20/2015 7:57 AM, Dave Caroline wrote:
> It might help to draw a diagram showing the electronics (drives
> modules etc) and where they are grounded showing outlines of the
> cases.
>
> This is to get an idea where any common mode interference signals can come 
> from.
>
> Also pictures of the wiring with annotation of wire bundles to get an
> idea of any capacitive or inductive coupling.
>
> Dave Caroline
>
> On 20/12/2015, John Thornton  wrote:
>> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
>> all the Anilam controls a while back. I've retained the drives and power
>> supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>>   From the get go I've had problems with the electronics on this machine.
>> The VFD is controlled by modbus via the gs2 component. The VFD gets
>> reset to default parameters all the time from noise on the modbus. the
>> 5i25 get sserial errors. The sserial errors are so bad now it won't even
>> move an axis. The spindle works ok. The power supply is a simple bridge
>> rectifier with a huge blue cap and a large power resistor across the cap.
>>
>> Peter keeps telling me it's a grounding issue so where do I start
>> looking and what do I need to do?
>>
>> Thanks
>> JT
>>
>> --
>> ___
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>>
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Re: [Emc-users] Grounding Issues

[John Thornton]

I'll start with a couple of photos of the el cabinets before breakfast 
and get more details after.

http://gnipsel.com/images/bp-knee-mill/bpel01.jpg
http://gnipsel.com/images/bp-knee-mill/bpel02.jpg

JT


On 12/20/2015 7:57 AM, Dave Caroline wrote:
> It might help to draw a diagram showing the electronics (drives
> modules etc) and where they are grounded showing outlines of the
> cases.
>
> This is to get an idea where any common mode interference signals can come 
> from.
>
> Also pictures of the wiring with annotation of wire bundles to get an
> idea of any capacitive or inductive coupling.
>
> Dave Caroline
>
> On 20/12/2015, John Thornton  wrote:
>> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
>> all the Anilam controls a while back. I've retained the drives and power
>> supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>>   From the get go I've had problems with the electronics on this machine.
>> The VFD is controlled by modbus via the gs2 component. The VFD gets
>> reset to default parameters all the time from noise on the modbus. the
>> 5i25 get sserial errors. The sserial errors are so bad now it won't even
>> move an axis. The spindle works ok. The power supply is a simple bridge
>> rectifier with a huge blue cap and a large power resistor across the cap.
>>
>> Peter keeps telling me it's a grounding issue so where do I start
>> looking and what do I need to do?
>>
>> Thanks
>> JT
>>
>> --
>> ___
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>>
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Re: [Emc-users] Grounding Issues

[Marius Liebenberg]

John
Some things to look for.
1: Make sure that you field supply is not grounded to the same ground as 
the VFD. I.E the 24v Filed supply must be floating.
2: All cables must be screened where possible.
3: Screen must only be connected at the source and and to one single 
place to the physical earth of the box as well as the mains earth.
4: Earth must only be connected at one single point (star connection)

I had a similar problem with my lathe and found in the end that my 
spindle motor cage was not physical earth and caused huge noise.




>I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
>all the Anilam controls a while back. I've retained the drives and 
>power
>supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>  From the get go I've had problems with the electronics on this 
>machine.
>The VFD is controlled by modbus via the gs2 component. The VFD gets
>reset to default parameters all the time from noise on the modbus. the
>5i25 get sserial errors. The sserial errors are so bad now it won't 
>even
>move an axis. The spindle works ok. The power supply is a simple bridge
>rectifier with a huge blue cap and a large power resistor across the 
>cap.
>
>Peter keeps telling me it's a grounding issue so where do I start
>looking and what do I need to do?
>
>Thanks
>JT
>
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Re: [Emc-users] Grounding Issues

[John Thornton]

On 12/20/2015 8:37 AM, Gene Heskett wrote:
> Start with a roll of flat braid equ to a 8 or 10 gauge wire. Establish a
> bolt to the case of the controller as a master ground, and make sure
> everything that references ground in the controller box is grounded at
> this bolt.
>
> Tie this bolt to the buildings static ground using that pin of the
> controllers power cable, BUT not to the building supply neutral as thats
> usually noisy as can be.  Or to a real ground rod but that may have a
> considerable damaging joltage on it when there is lightning nearby so is
> both against the NEC and would be poor practice.
I'll start here, I see 4 places where things are grounded, the encoders 
all have a ground connection to the electrical cabinet and one on the 
other cabinet where the VFD lives. I know without looking that every 
panel has the neutral bonded to ground and I have two ground rods one 
for the house and one for the garage/shop (one panel for each one back 
to back). I do think this is local to the machine as I have other 
machines in the shop that do not have this problem. Let me study the 
grounds a bit...
> Then extend that ground, using this braid, to the bridgeports main
> casting, and perhaps also to the table and knee as the lube oil in the
> ways might preclude a really good ground on the table without it.
>
> Extend that ground from that bolt to the computers case if it is
> separated from the controller box.
>
> This is called a star ground system, where everything is common at this
> bolt.  If you can disconnect each wire from that bolt, and still measure
> continuity of 200 ohms or less from the bolt to the disconnected wire,
> then that wire has an unwanted ground somewhere, run it down and remove
> it, you want that to be "grounded" only at that bolt.
>
> The idea is that even if it does bounce a bit from a nearby lightning
> strike, it all bounces in unison with no big voltage drops between
> anything that can damage it, or induce noise that would be miss-detected
> as a signal.
>
> Years ago when I was screwing with vz & their bad copper, I figured on
> losing a modem everytime I heard thunder. Getting PO'd, I first opened
> up the wall a bit, pulled out the duplex that was going to power what I
> had in mind, and soldered all the connections in that box. Then I bought
> the biggest surge arrestor I could find, one that had phone line & cable
> tv arrestors in it.  And I bought the biggest home UPS I could find.
> Everything in this room but the lights is plugged in either to that UPS
> or that surge arrestor, and both are plugged into this all soldered
> duplex. Now lightning can hit the pole my transformer is on, possibly
> bouncing everything in this room by 100 kilovolts, but it all bounces in
> unison and I haven't lost a modem or anything else that I could
> associate the loss with local lightning strikes. But since I did get,
> from a wired keyboard I was typing on at the time, a really good jolt
> thru my fingers like shuffling ones feet on the rug and then grabbing
> the doorknob, but it didn't hurt the computer or the keyboard, but I now
> use wireless keyboard and mice.
>
> If the frame of the bridgeport is grounded thru other means, such as a
> 3rd pin on a power cable, this should be defeated in order to remove the
> potential ground loop which can be a source of quite a bit of induced
> noise.
>
> Motor drive, and feedback cables from the motors should be shielded, with
> the shields cut off at the motor ends of the cable but tied to this bolt
> at the controller end, thereby interrupting that potential ground loop.
>
> The general idea is to have one common "ground" point, even if its is not
> an earthen ground. That s/b, by the NEC, at the service entrance, a
> minimum of two full rods driven 6 feet apart, with an 8 gauge wire
> bonding them to the buildings static ground for the 3rd pin of all the
> duplexes and neutral from the pole drop, the only place it is legal to
> interconnect them.  Hanging an amprobe on any of the bare static wires
> in the service box should get you a zero reading regardless of what is
> powered up.  If you do see a reading, something out on that circuit is
> miss-wired. Fix it. Its just good practice.
>
> It and I, may sound arbitrary John, but it works.  And its NEC legal.
> If you have a decent scope, just waving a probe around with the gain
> turned up near suspected noise sources can be very educational.
>
> I've had to follow too many electricians around, fixing their mix-n-match
> attitude about static and neutral being the same thing, way too many
> times.
>
> Let us know what you did find when you've cleaned up the problem, please.
>
> Cheers, Gene Heskett


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Re: [Emc-users] Grounding Issues

[Dave Caroline]

It might help to draw a diagram showing the electronics (drives
modules etc) and where they are grounded showing outlines of the
cases.

This is to get an idea where any common mode interference signals can come from.

Also pictures of the wiring with annotation of wire bundles to get an
idea of any capacitive or inductive coupling.

Dave Caroline

On 20/12/2015, John Thornton  wrote:
> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
> all the Anilam controls a while back. I've retained the drives and power
> supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>  From the get go I've had problems with the electronics on this machine.
> The VFD is controlled by modbus via the gs2 component. The VFD gets
> reset to default parameters all the time from noise on the modbus. the
> 5i25 get sserial errors. The sserial errors are so bad now it won't even
> move an axis. The spindle works ok. The power supply is a simple bridge
> rectifier with a huge blue cap and a large power resistor across the cap.
>
> Peter keeps telling me it's a grounding issue so where do I start
> looking and what do I need to do?
>
> Thanks
> JT
>
> --
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Re: [Emc-users] Grounding Issues

[John Thornton]

Back from shopping...

Pencil sketch of the power side
http://gnipsel.com/images/bp-knee-mill/bpel03.jpg

Incoming terminal block on left panel where extra ground is
http://gnipsel.com/images/bp-knee-mill/bpel04.jpg

next terminal block on right panel
http://gnipsel.com/images/bp-knee-mill/bpel05.jpg

JT

On 12/20/2015 8:37 AM, Gene Heskett wrote:
> On Sunday 20 December 2015 08:20:38 John Thornton wrote:
>
>> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
>> all the Anilam controls a while back. I've retained the drives and
>> power supply and added a GS2 VFD for the spindle. I have a 5i25 7i77
>> setup. From the get go I've had problems with the electronics on this
>> machine. The VFD is controlled by modbus via the gs2 component. The
>> VFD gets reset to default parameters all the time from noise on the
>> modbus. the 5i25 get sserial errors. The sserial errors are so bad now
>> it won't even move an axis. The spindle works ok. The power supply is
>> a simple bridge rectifier with a huge blue cap and a large power
>> resistor across the cap.
>>
>> Peter keeps telling me it's a grounding issue so where do I start
>> looking and what do I need to do?
>>
>> Thanks
>> JT
>>
> Start with a roll of flat braid equ to a 8 or 10 gauge wire. Establish a
> bolt to the case of the controller as a master ground, and make sure
> everything that references ground in the controller box is grounded at
> this bolt.
>
> Tie this bolt to the buildings static ground using that pin of the
> controllers power cable, BUT not to the building supply neutral as thats
> usually noisy as can be.  Or to a real ground rod but that may have a
> considerable damaging joltage on it when there is lightning nearby so is
> both against the NEC and would be poor practice.
>
> Then extend that ground, using this braid, to the bridgeports main
> casting, and perhaps also to the table and knee as the lube oil in the
> ways might preclude a really good ground on the table without it.
>
> Extend that ground from that bolt to the computers case if it is
> separated from the controller box.
>
> This is called a star ground system, where everything is common at this
> bolt.  If you can disconnect each wire from that bolt, and still measure
> continuity of 200 ohms or less from the bolt to the disconnected wire,
> then that wire has an unwanted ground somewhere, run it down and remove
> it, you want that to be "grounded" only at that bolt.
>
> The idea is that even if it does bounce a bit from a nearby lightning
> strike, it all bounces in unison with no big voltage drops between
> anything that can damage it, or induce noise that would be miss-detected
> as a signal.
>
> Years ago when I was screwing with vz & their bad copper, I figured on
> losing a modem everytime I heard thunder. Getting PO'd, I first opened
> up the wall a bit, pulled out the duplex that was going to power what I
> had in mind, and soldered all the connections in that box. Then I bought
> the biggest surge arrestor I could find, one that had phone line & cable
> tv arrestors in it.  And I bought the biggest home UPS I could find.
> Everything in this room but the lights is plugged in either to that UPS
> or that surge arrestor, and both are plugged into this all soldered
> duplex. Now lightning can hit the pole my transformer is on, possibly
> bouncing everything in this room by 100 kilovolts, but it all bounces in
> unison and I haven't lost a modem or anything else that I could
> associate the loss with local lightning strikes. But since I did get,
> from a wired keyboard I was typing on at the time, a really good jolt
> thru my fingers like shuffling ones feet on the rug and then grabbing
> the doorknob, but it didn't hurt the computer or the keyboard, but I now
> use wireless keyboard and mice.
>
> If the frame of the bridgeport is grounded thru other means, such as a
> 3rd pin on a power cable, this should be defeated in order to remove the
> potential ground loop which can be a source of quite a bit of induced
> noise.
>
> Motor drive, and feedback cables from the motors should be shielded, with
> the shields cut off at the motor ends of the cable but tied to this bolt
> at the controller end, thereby interrupting that potential ground loop.
>
> The general idea is to have one common "ground" point, even if its is not
> an earthen ground. That s/b, by the NEC, at the service entrance, a
> minimum of two full rods driven 6 feet apart, with an 8 gauge wire
> bonding them to the buildings static ground for the 3rd pin of all the
> duplexes and neutral from the pole drop, the only place it is legal to
> interconnect them.  Hanging an amprobe on any of the bare static wires
> in the service box should get you a zero reading regardless of what is
> powered up.  If you do see a reading, something out on that circuit is
> miss-wired. Fix it. Its just good practice.
>
> It and I, may sound arbitrary John, but it works.  And its NEC legal.
> If you have a 

Re: [Emc-users] Grounding Issues

[Kirk Wallace]

On 12/20/2015 05:20 AM, John Thornton wrote:
> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've removed
> all the Anilam controls a while back. I've retained the drives and power
> supply and added a GS2 VFD for the spindle. I have a 5i25 7i77 setup.
>   From the get go I've had problems with the electronics on this machine.

I have had good results (noise on encoder lines) by adding mains filters 
to my VFD power inputs.

The shiny box here:
http://www.wallacecompany.com/cnc_lathe/HNC/00024-1a.jpg

I suspect any switching power circuit might benefit from installing an 
input filter.

-- 
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/

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Re: [Emc-users] Grounding Issues

[Dave Caroline]

The din rail in the 05 pic is that real tight to the back panel (add
star washers to cut through paint), make sure the green/yellow blocks
have the middle screw tight.

One mighty thin grounding wire in bpel04.jpg, also could add star
washer to cut through paint

You could measure the ground resistance too if you can.

Others are likely to mention you have two grounds rather than a star
ground. Make sure cases are tight to frame to guarantee continuity

Dave Caroline

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Re: [Emc-users] Grounding Issues

[Gene Heskett]

On Sunday 20 December 2015 12:15:21 John Thornton wrote:

> Back from shopping...
>
> Pencil sketch of the power side
> http://gnipsel.com/images/bp-knee-mill/bpel03.in
the left box probably needs the paint cleaned off under it, and maybe a 
star washer under the spade lug for extra connection bite. And there 
ought to be a similar ground to the box in the right box. But as sub 
boxes generally have isolated busses for the static (bare wires in the 
romex */3 wires) in order to bot short circuit the connection at the 
main entrance a foot or so from the meterhead.

> Incoming terminal block on left panel where extra ground is
> http://gnipsel.com/images/bp-knee-mill/bpel04.jpg

Here I cannot see the above green wire, the static, while connected to 
the  to the box, but it does not leave to connect the rest of the stuff, 
just the white (neutral) and black (127 hot) wires leaving are all I see 
leaving. Tieing to the box, is to ground the box to the static 
grounding.

> next terminal block on right panel
> http://gnipsel.com/images/bp-knee-mill/bpel05.jpg
>
And here, unless its in the block mounting for the two green wires I can 
see, and I am not at all familiar with that style of terminal block, 
they are floating.  Are the two pieces of SJ I see coming in at the top, 
source or load?

Offhand, it does tend to look like a noise factory from here. :(  Those 
green wires should come from the real ground at the service entrance and 
go all the way to that single point bolt in the driver cabinet wall, 
then from there to everything else as a star ground.

> JT
>
> On 12/20/2015 8:37 AM, Gene Heskett wrote:
> > On Sunday 20 December 2015 08:20:38 John Thornton wrote:
> >> I have a BP knee mill with an Anilam 1100M CNC kit on it. I've
> >> removed all the Anilam controls a while back. I've retained the
> >> drives and power supply and added a GS2 VFD for the spindle. I have
> >> a 5i25 7i77 setup. From the get go I've had problems with the
> >> electronics on this machine. The VFD is controlled by modbus via
> >> the gs2 component. The VFD gets reset to default parameters all the
> >> time from noise on the modbus. the 5i25 get sserial errors. The
> >> sserial errors are so bad now it won't even move an axis. The
> >> spindle works ok. The power supply is a simple bridge rectifier
> >> with a huge blue cap and a large power resistor across the cap.
> >>
> >> Peter keeps telling me it's a grounding issue so where do I start
> >> looking and what do I need to do?
> >>
> >> Thanks
> >> JT
> >
> > Start with a roll of flat braid equ to a 8 or 10 gauge wire.
> > Establish a bolt to the case of the controller as a master ground,
> > and make sure everything that references ground in the controller
> > box is grounded at this bolt.
> >
> > Tie this bolt to the buildings static ground using that pin of the
> > controllers power cable, BUT not to the building supply neutral as
> > thats usually noisy as can be.  Or to a real ground rod but that may
> > have a considerable damaging joltage on it when there is lightning
> > nearby so is both against the NEC and would be poor practice.
> >
> > Then extend that ground, using this braid, to the bridgeports main
> > casting, and perhaps also to the table and knee as the lube oil in
> > the ways might preclude a really good ground on the table without
> > it.
> >
> > Extend that ground from that bolt to the computers case if it is
> > separated from the controller box.
> >
> > This is called a star ground system, where everything is common at
> > this bolt.  If you can disconnect each wire from that bolt, and
> > still measure continuity of 200 ohms or less from the bolt to the
> > disconnected wire, then that wire has an unwanted ground somewhere,
> > run it down and remove it, you want that to be "grounded" only at
> > that bolt.
> >
> > The idea is that even if it does bounce a bit from a nearby
> > lightning strike, it all bounces in unison with no big voltage drops
> > between anything that can damage it, or induce noise that would be
> > miss-detected as a signal.
> >
> > Years ago when I was screwing with vz & their bad copper, I figured
> > on losing a modem everytime I heard thunder. Getting PO'd, I first
> > opened up the wall a bit, pulled out the duplex that was going to
> > power what I had in mind, and soldered all the connections in that
> > box. Then I bought the biggest surge arrestor I could find, one that
> > had phone line & cable tv arrestors in it.  And I bought the biggest
> > home UPS I could find. Everything in this room but the lights is
> > plugged in either to that UPS or that surge arrestor, and both are
> > plugged into this all soldered duplex. Now lightning can hit the
> > pole my transformer is on, possibly bouncing everything in this room
> > by 100 kilovolts, but it all bounces in unison and I haven't lost a
> > modem or anything else that I could associate the loss with local
> > lightning strikes. But since I did get, from a wired 

Re: [Emc-users] Grounding Issues

[Gene Heskett]

On Sunday 20 December 2015 13:37:38 John Thornton wrote:

> On 12/20/2015 11:47 AM, Gene Heskett wrote:
> > On Sunday 20 December 2015 12:15:21 John Thornton wrote:
> >> Back from shopping...
> >>
> >> Pencil sketch of the power side
> >> http://gnipsel.com/images/bp-knee-mill/bpel03.in
> >
> > the left box probably needs the paint cleaned off under it, and
> > maybe a star washer under the spade lug for extra connection bite.
> > And there ought to be a similar ground to the box in the right box.
> > But as sub boxes generally have isolated busses for the static (bare
> > wires in the romex */3 wires) in order to bot short circuit the
> > connection at the main entrance a foot or so from the meterhead.
> >
> >> Incoming terminal block on left panel where extra ground is
> >> http://gnipsel.com/images/bp-knee-mill/bpel04.jpg
> >
> > Here I cannot see the above green wire, the static, while connected
> > to the  to the box, but it does not leave to connect the rest of the
> > stuff, just the white (neutral) and black (127 hot) wires leaving
> > are all I see leaving. Tieing to the box, is to ground the box to
> > the static grounding.
> >
> >> next terminal block on right panel
> >> http://gnipsel.com/images/bp-knee-mill/bpel05.jpg
> >
> > And here, unless its in the block mounting for the two green wires I
> > can see, and I am not at all familiar with that style of terminal
> > block, they are floating.  Are the two pieces of SJ I see coming in
> > at the top, source or load?
>
> The green/yellow terminal blocks are standard ground blocks, the
> center screw tightens a gripper that forces a tight metal to metal
> contact with the DIN rail and the terminals. It's very much grounded
> to the DIN rail and the DIN rail is fastened to the back plane with
> welded on studs and star washers and nuts.
>
That makes me feel a lot better John.

But I am shortly going to be out of pocket till Monday afternoon. 
Cataract fixings in the XYL's right eye are scheduled for first thing in 
the morning, so we've reserved a room about a mile from the O.R.

> http://www.automationdirect.com/adc/Shopping/Catalog/Terminal_Blocks/D
>INnector_DIN-Rail_Terminal_Blocks/Ground_Terminal_Blocks/DN-G10
>
> They are very expensive...

Figures. :(

Do you have an oscilloscope?

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)
Some mill pix are at:
Genes Web page 

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Re: [Emc-users] Grounding Issues

[John Dammeyer]

Hi John,

It sounds as if you have two AC lines coming into the machine.  One for the
controller and one for the VFD.  The comments about a single star ground
point are standard industry practice.  One breaker at the panel which
protects the wire to the machine.  Another breaker inside the machine that
protects the equipment.

The Earth (green) comes in and is connected to a welded stud with a ring
terminal, not a spade and double nutted so it can't possibly come loose.
>From that point your controller and VFD are run.Never ever rely on the
frame to carry the AC Ground (Earth) from one section to another.  

DC grounds are isolated from Earth Ground.  You can, connect the DC power
supply minus to the Earth ground and it may even be a code requirement where
you are.  Be aware, some PCs do this inside their power supply as do other
types of COTS hardware.

And here is the problem you have to watch out for.  Just because your DC
volt meter reads continuity  (Zero Ohms)  between all the ground points
doesn't mean that there is actually a path of lowest resistance following
what you think it should.

The moment you get into the switching power world which includes the VFD,
Stepper Motors and Servos along with switching power supplies you get
something called impedance.  That's based on the DC resistance (usually low)
and a combination of the wire inductance and capacitance and frequency.  

Depending on how things are wired and routed the impedance of the return
signal of the VFD may be lower through the RS232 (RS485) shield than it is
through the green wire or even the shield around the power cable.  So just
imagine the very noisy VFD signal returns through the communication shield
because that has an impedance of 200 Ohms while the green wire has 1K.
That's problem #1.

There's two types of electrical noise.  Electrical coupling and magnetic
coupling.  Electrical you shield against.  Usually with the shield tied to a
common earth somewhere.   
Magnetic coupling is the same thing that makes a transformer or a motor
function.  A rapidly changing magnetic field caused by rapidly changing
current in a wire is coupled onto another wire that is in close proximity.
Shielding doesn't protect against that. Twisted pairs do to a certain
extent.  

The best protection is distance.  That's why you don't run the VFD power or
Servo power tightly tie wrapped to the encoder signal.  

Therefore put the AC power side for the VFD on one side of the cabinet and
run the control signals as far away as possible.

There are lots of books written on this subject and probably as many
opinions on what to do.  Ground shield at both ends.  Ground at one end.
Don't ground.   Twist the wires.  Don't twist the wires.  

Start with the Star Grounding.  Make sure there aren't any DC paths that are
unexpected as explained earlier.   Then start looking at how the noisy
signals might find their way back through alternate paths.  Filters,
Ferrites are all useful to block the signals.  Always best to block at the
source.

John






> -Original Message-
> From: John Thornton [mailto:j...@gnipsel.com]
> Sent: December-20-15 10:27 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Grounding Issues
> 
> 
> I have a line reactor for the VFD but I've never hooked it up.
> 
> http://www.automationdirect.com/adc/Shopping/Catalog/Drives/AC_Drive
> _%28VFD%29_Spare_Parts_-a-_Accessories/AC_Line_Reactors/LR-23P0-1PH
> 
> Speaking of VFD's mine is grounded to the breaker panel and not in the
> machine anywhere. When I check from the ground terminal to the panel I
> get 0 ohms so I assume that the back of the VFD is grounded to the
> ground lug on the VFD.
> 
> JT


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Re: [Emc-users] Grounding Issues

[tom-emc]

I bought some Weidmuller WPE6 off ebay for less than $1/ea.  In fact, I bought 
various DIN terminal blocks off ebay for a fraction of the price new.  I’d 
watch ebay, you may find a deal…
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XWEIDMULLER+WPE6.TRS0&_nkw=WEIDMULLER+WPE6&_sacat=0

-Tom


> On Dec 20, 2015, at 1:37 PM, John Thornton  wrote:
> The green/yellow terminal blocks are standard ground blocks, the center 
> screw tightens a gripper that forces a tight metal to metal contact with 
> the DIN rail and the terminals. It's very much grounded to the DIN rail 
> and the DIN rail is fastened to the back plane with welded on studs and 
> star washers and nuts.
> 
> http://www.automationdirect.com/adc/Shopping/Catalog/Terminal_Blocks/DINnector_DIN-Rail_Terminal_Blocks/Ground_Terminal_Blocks/DN-G10
>  
> 
> 
> They are very expensive...

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Re: [Emc-users] Grounding Issues

[Rafael]

John,

On 12/20/2015 06:31 AM, John Thornton wrote:
> I'll start with a couple of photos of the el cabinets before breakfast
> and get more details after.
>
> http://gnipsel.com/images/bp-knee-mill/bpel01.jpg
> http://gnipsel.com/images/bp-knee-mill/bpel02.jpg
>
> JT
>

We used to have cabinet grounding problems on PDP-11 series until we 
connected ground wires from each cabinet, doors, and computer chassis to 
one point in the power entry cabinet. Wires were thick, over 2mm or so 
if I remember correctly.

As Gene and others have pointed out, star configuration is the only way 
to go. As far as I can see from your pictures (bpel01.jpg right top 
corner for example), you seem to have more than one ground connection in 
the box. That seem OK logically but it's not good for a number of 
reasons, resistance, ground loops, RF. Box is not a GND star center. 
Metal brackets don't seem to be grounded to one point either but they 
have circuit boards with spacers on them.

You can get a copper grounding bar with holes and screws in hardware 
store to create a large ground post for everything in the box. Outside 
ground from power cable needs to be attached to it first then other 
things including box, the door, and shielded wires between the 
electronic devices. Don't forget the fans.

Since this is a retrofit (?) I would remove all ground wires, check for 
corrosion or electrolytic effects, and connect them to one ground. Note 
that a mix of steel washers and copper wires has it's own issues. In 
addition, I would turn all screws on boards back and forth to make 
better connections also.

Next thing is PSU. Old electrolytic caps may not be good enough anymore, 
there might be RF noise problem between the circuits, wires too thin to 
carry the current, etc.

-- 
Rafael

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Re: [Emc-users] [was] Anybody know where to find a pdf on the HOYMK SSR40DA SSR?

[Gene Heskett]

On Sunday 20 December 2015 04:27:39 Gene Heskett wrote:

[... back to readable size, on my charge-pump detection to run the SSR's]

> Has anyone else concocted such a circuit, and were you able to get
> enough pump power out of it running the BoB on 5 volts, with the pump
> at 500 hz, to run an SSR without resorting to an external current
> booster?

Now I am both bumfuzzled and confused. There really ought to be a formula 
for calculating the size of the capacitors needed, but there is 
absolutely zip in ITT #5, nor in the hambook of about the same vintage. 

So, I guess its build it, and test it by the old fashioned cuss & cry 
method. Seems to me there really ought to be, in the year 2015, a plug 
in the blanks formula for that.  Sigh...

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)
Some mill pix are at:
Genes Web page 

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