Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-25 Thread Gene Heskett 
On Sunday 25 December 2016 17:58:00 Gene Heskett wrote:

> On Sunday 25 December 2016 17:23:08 Chris Albertson wrote:
> > Have you tried typing "sudo  synaptic-pkexec" rather than "
> > synaptic-pkexec" and is your logged in user in the  /etc/sudoers
> > file?
> >
> > Also you can alway just use "apt" or apt-get" for package management
> > at the command prompt.  Much simpler and faster.
>
> Yes it is, no question about that.
>
> But what package? apt apparently has no way to show you whats missing
> that is killing your x. I do have an /etc/init.d/x11-common, which has
> to be running if I want it to display on another machine.  And I do
> have it running that way by putting a 10 in front of the error and
> ferror values in he ini files [joint] settings.
>
> With synaptic its a piece of cake to scroll down the the X stuffs and
> look thru the list for the usual suspects, click, mark install, click
> apply and ok, done. Reboot if needed.
>
> The logs are either non-existant, or silent of any clues that might
> point to a missing package.  And lightdm is installed.
> However, /etc/lightdm/lightdm.conf has an empty [seat] stanza.
>
> Please, you who are running an r-pi, with the x gui working, send me
> the output of
>
>  grep -v '#' /etc/lightdm/lightdm.conf
>
> The one I have doesn't even start a "default seat".
> I've enabled that, and we'll see what logs if any are generated.
>
> Thanks.

Well, with that, and the 3rd option of logging into x chosen in 
raspi-config>boot options, (if I pick the bottom selection there, I do 
not have a mouse, so I can't focus the keyboard on the little terinal 
window it opens) I do get a small terminal in the upper left corner of 
the screen, which is not movable or resizable, but I can run linuxcnc 
from it.

But seriously, I need the output of the above command.  Hum, I'll see if 
I can get it off one of the other sd cards.  Hmm, no diff except it 
doesn't have the default session enabled.  My headache just got worse.

I've had lcnc freeze but the pulldown to quit still works. The power and 
enable buttons are turned off and do not respond to any mouse clicks. So 
there is no way to re-enable anything, only restart it. The watchdog led 
is off on the 7i90 when this happens, so the servo thread is still 
running I think.

All my boys have now checked in and wished us a Merry Christmas, and I 
did get the z motor to move an inch or so, so I am seeing progress, 
which makes me happier.

And I hope you all have had a day suitable to fit the reason for the 
season too.

Thanks everybody.

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)
Genes Web page 

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-25 Thread Gene Heskett 
On Sunday 25 December 2016 17:23:08 Chris Albertson wrote:

> Have you tried typing "sudo  synaptic-pkexec" rather than "
> synaptic-pkexec" and is your logged in user in the  /etc/sudoers
> file?
>
There is now a group called sudoers, and pi is a member of that group.

> Also you can alway just use "apt" or apt-get" for package management
> at the command prompt.  Much simpler and faster.
>
> On Sun, Dec 25, 2016 at 9:11 AM, Gene Heskett  
wrote:
> > Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
> > permitted by applicable law.
> > Last login: Sat Dec 24 19:49:11 2016 from coyote.coyote.den
> > pi@raspberrypi:~ $ synaptic-pkexec
> >  AUTHENTICATING FOR com.ubuntu.pkexec.synaptic ===
> > Authentication is required to run the Synaptic Package Manager
> > Authenticating as: root
> > Password:
> > polkit-agent-helper-1: pam_authenticate failed: Authentication
> > failure  AUTHENTICATION FAILED ===
> > Error executing command as another user: Not authorized
> >
> > This incident has been reported.
> > pi@raspberrypi:~ $ synaptic-pkexec
> >  AUTHENTICATING FOR com.ubuntu.pkexec.synaptic ===
> > Authentication is required to run the Synaptic Package Manager
> > Authenticating as: root
> > Password:
> > polkit-agent-helper-1: error response to PolicyKit daemon:
> > GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: No session for
> > cookie
> >  AUTHENTICATION FAILED ===
> > Error executing command as another user: Not authorized
> >
> > This incident has been reported.
> > ==
> > I tried both the root pw and mine.
> >
> > WTHeck is this com.ubuntu.pkexec.synaptic BS?  Of course its wrong,
> > but how can this be fixed so I can run synaptic from a remote login?
> >
> > Or, how do I make this machine accept a display of 10:  ??
> >
> > Thank you all & Merry Christmas everybody
> >
> > 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)
> > Genes Web page 
> >
> > 
> >-- Developer Access Program for Intel Xeon Phi Processors
> > Access to Intel Xeon Phi processor-based developer platforms.
> > With one year of Intel Parallel Studio XE.
> > Training and support from Colfax.
> > Order your platform today.http://sdm.link/intel
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users


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)
Genes Web page 

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-25 Thread Gene Heskett 
On Sunday 25 December 2016 17:23:08 Chris Albertson wrote:

> Have you tried typing "sudo  synaptic-pkexec" rather than "
> synaptic-pkexec" and is your logged in user in the  /etc/sudoers
> file?
>
> Also you can alway just use "apt" or apt-get" for package management
> at the command prompt.  Much simpler and faster.

Yes it is, no question about that.

But what package? apt apparently has no way to show you whats missing 
that is killing your x. I do have an /etc/init.d/x11-common, which has 
to be running if I want it to display on another machine.  And I do have 
it running that way by putting a 10 in front of the error and ferror 
values in he ini files [joint] settings.

With synaptic its a piece of cake to scroll down the the X stuffs and 
look thru the list for the usual suspects, click, mark install, click 
apply and ok, done. Reboot if needed.

The logs are either non-existant, or silent of any clues that might point 
to a missing package.  And lightdm is installed.  
However, /etc/lightdm/lightdm.conf has an empty [seat] stanza.

Please, you who are running an r-pi, with the x gui working, send me the 
output of

 grep -v '#' /etc/lightdm/lightdm.conf

The one I have doesn't even start a "default seat".
I've enabled that, and we'll see what logs if any are generated.

Thanks.
>
> On Sun, Dec 25, 2016 at 9:11 AM, Gene Heskett  
wrote:
> > Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
> > permitted by applicable law.
> > Last login: Sat Dec 24 19:49:11 2016 from coyote.coyote.den
> > pi@raspberrypi:~ $ synaptic-pkexec
> >  AUTHENTICATING FOR com.ubuntu.pkexec.synaptic ===
> > Authentication is required to run the Synaptic Package Manager
> > Authenticating as: root
> > Password:
> > polkit-agent-helper-1: pam_authenticate failed: Authentication
> > failure  AUTHENTICATION FAILED ===
> > Error executing command as another user: Not authorized
> >
> > This incident has been reported.
> > pi@raspberrypi:~ $ synaptic-pkexec
> >  AUTHENTICATING FOR com.ubuntu.pkexec.synaptic ===
> > Authentication is required to run the Synaptic Package Manager
> > Authenticating as: root
> > Password:
> > polkit-agent-helper-1: error response to PolicyKit daemon:
> > GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: No session for
> > cookie
> >  AUTHENTICATION FAILED ===
> > Error executing command as another user: Not authorized
> >
> > This incident has been reported.
> > ==
> > I tried both the root pw and mine.
> >
> > WTHeck is this com.ubuntu.pkexec.synaptic BS?  Of course its wrong,
> > but how can this be fixed so I can run synaptic from a remote login?
> >
> > Or, how do I make this machine accept a display of 10:  ??
> >
> > Thank you all & Merry Christmas everybody
> >
> > 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)
> > Genes Web page 
> >
> > 
> >-- Developer Access Program for Intel Xeon Phi Processors
> > Access to Intel Xeon Phi processor-based developer platforms.
> > With one year of Intel Parallel Studio XE.
> > Training and support from Colfax.
> > Order your platform today.http://sdm.link/intel
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users


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)
Genes Web page 

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-25 Thread Chris Albertson 
Have you tried typing "sudo  synaptic-pkexec" rather than "
synaptic-pkexec" and is your logged in user in the  /etc/sudoers
file?

Also you can alway just use "apt" or apt-get" for package management
at the command prompt.  Much simpler and faster.

On Sun, Dec 25, 2016 at 9:11 AM, Gene Heskett  wrote:
> Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
> permitted by applicable law.
> Last login: Sat Dec 24 19:49:11 2016 from coyote.coyote.den
> pi@raspberrypi:~ $ synaptic-pkexec
>  AUTHENTICATING FOR com.ubuntu.pkexec.synaptic ===
> Authentication is required to run the Synaptic Package Manager
> Authenticating as: root
> Password:
> polkit-agent-helper-1: pam_authenticate failed: Authentication failure
>  AUTHENTICATION FAILED ===
> Error executing command as another user: Not authorized
>
> This incident has been reported.
> pi@raspberrypi:~ $ synaptic-pkexec
>  AUTHENTICATING FOR com.ubuntu.pkexec.synaptic ===
> Authentication is required to run the Synaptic Package Manager
> Authenticating as: root
> Password:
> polkit-agent-helper-1: error response to PolicyKit daemon:
> GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: No session for
> cookie
>  AUTHENTICATION FAILED ===
> Error executing command as another user: Not authorized
>
> This incident has been reported.
> ==
> I tried both the root pw and mine.
>
> WTHeck is this com.ubuntu.pkexec.synaptic BS?  Of course its wrong, but
> how can this be fixed so I can run synaptic from a remote login?
>
> Or, how do I make this machine accept a display of 10:  ??
>
> Thank you all & Merry Christmas everybody
>
> 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)
> Genes Web page 
>
> --
> Developer Access Program for Intel Xeon Phi Processors
> Access to Intel Xeon Phi processor-based developer platforms.
> With one year of Intel Parallel Studio XE.
> Training and support from Colfax.
> Order your platform today.http://sdm.link/intel
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users



-- 

Chris Albertson
Redondo Beach, California

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-25 Thread Jon Elson 
On 12/25/2016 11:11 AM, Gene Heskett wrote:
> On Saturday 24 December 2016 15:59:31 Chris Albertson wrote:
>
>> Read the little write up at the Mesa site about cable length.   They
>> claim ribbon cable is the worst and to only use it for very short
>> runs, 2 or 3 feet at most. They suggest using "real" parallel
>> cables made with twisted pairs and shielding for longer runs.  Using
>> one of their fancy IEEE cables you can go up to 25 or 30 feet, half
>> that with a normal round cable and half that again with ribbon cable.
>>
>
I have made up a number of special-purpose cables for 
interfacing parallel ports to things, including the HPIB 
bus.  You can take the twisted-pair ribbon cable and 
hand-wire the signals and grounds to appropriate pins, and 
get excellent operation up to 25 or more feet.  Every signal 
gets a pair of wires, one signal and one ground.
But, making these is tedious.

Jon

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-25 Thread Gene Heskett 
On Saturday 24 December 2016 15:59:31 Chris Albertson wrote:

> Read the little write up at the Mesa site about cable length.   They
> claim ribbon cable is the worst and to only use it for very short
> runs, 2 or 3 feet at most. They suggest using "real" parallel
> cables made with twisted pairs and shielding for longer runs.  Using
> one of their fancy IEEE cables you can go up to 25 or 30 feet, half
> that with a normal round cable and half that again with ribbon cable.
>
That would be about 6 feet, I'd assume src terminated. Mesa's cables, 
with plugs attached, I'd have to figure out how to get the plug past the 
3/4" holes presently in the box.  Even the ribbon that wide would need 
be to excavate and find some GreenLee punches I haven't used in 20 some 
years.

> For over 30 feet use some kind of differential signaling or fiber.
>
> There is nothing inherently bad about ribbon cable.  It is more about
> how it is driven.  It works well as a 50 ohm transition line if you
> terminate it at each end.  The old SCSI disk drives did that.

But not at 50 0hms! That ribbon cable, assuming every other wire is 
ground, has an impedance in the high tolerance end of 120 ohms. Assuming 
well by passed supply rails, the 220 from the signal line up to the 5 
volt rail, in parallel with the 330 to ground, simulates a 132 ohm 
parallel termination on each end.  Under ideal conditions the cable 
length limit is said to be 39 meters!

But that has one huge gotcha that the bean counters between engineering 
and the production floor, busy counting sheckles, substituted an Si 
diode for the schottky the engineers specified for the rail isolator, 
thereby dropping the nominally 5 volt bus, which should rest a logic 1  
at 3 volts, to about 2.6 volts, eating 400 mv of the logic 1's 600mv 
noise margin. Back in the day, when every midmarket tv station had half 
a dozen Amiga's doing graphics work, and crashing due to scsi bus 
errors, I had to fix every damned scsi card we ever put in an Amiga. And 
one of the two we had in pc's. No exceptions in the Amiga's. And I found 
some mistakes that were real hooodooozies.  Like the term resistor packs 
all installed end for end.  Or all the 6.3 volt electrolytic's installed 
on the 5 volt rails soldered in bas ackwards.  Surprisingly, those caps 
will last about a year that way, so by the time they start blowing their 
tops, any warranty of a $1500 68060 card was long expired.

Theres an awful lot of such stuff I've had to fix in the 66+ years I've 
chased electrons for a living, and at 82, I am still doing it 
occasionally. But understandably getting rusty too. So I ask lots of 
questions now. :)

> But 
> there is an upper limit on how fast you can push data down a parallel
> cable. This is why all the really fast computer interfaces are now
> serial
>
> Your problem might be because you are doing to much at once.  Can you
> get a one axis stepper motor to run slowly using GPIO and no FPGA
> card?  Does that work reliably through multiple upgrades and config
> changes or is it fragile?  Or even before that, can you install and
> update Linux and compile kernels and instal new drivers and run a web
> browsers and email and do upgrades and such reliably before using 
> RPi3 as a machine controller.

At this time, I would have to say that its damned fragile.

This msg sat behind the main window while I played a bit last night, and 
made it run with x remoted to this machine.  And I am seeing a data 
error that is causing it to throw joint errors, including a joint that 
is yet open pins on the 7i90 output connectors.

I am thinking that a study of the 7i90 pdf might have a clue, because the 
7i90 is still jumpered as shipped, but the r-pi is feeding it only a 3.3 
volt signal. (assumed, I have not pulled out the sampler and measured 
it, so I suppose thats next) In previous playing a month ago, I found if 
I could keep it moving the z axis at a typical rapid move rate, it did 
not throw the joint error while the z was moving. Only after it had 
stopped, did it error, always both joints. So IMO it almost has to be 
signal level caused data errors. The interconnect cable I made has all 8 
of the available grounds on the pi's 40 pin header, connected thru to 
the 8 available grounds of the 7i90's 26 pin connector. And with the box 
cover carrying the pi and 7i90 on its inside face held open, I cannot 
see radiated noise from the z axis driver, or its switching psu, getting 
back into the pi by any means than a possible ground loop.

Thats problem #1.

The second problem is that I can't make x run on the pi.  And without 
synaptic I can't see whats missing. It opens a black screen with what 
almost looks like a prompt at the upper left corner, but thats as far as 
it gets, and any recovery must be done from a login from one of the 
other machines here. But an xhost + in the terminal tab I am going to 
log in from, fails to allow me to run a package manager other than apt.

Screen

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Chris Albertson 
You are right, pushing high speed signal over long distances is not an
easy task.   It is no coincidence that the faster electronics are also
physically smaller.  With a given technology the way to go faster is
to get smaller.  This applies to CPU chips and also cables.

On Sat, Dec 24, 2016 at 1:44 PM, Bertho Stultiens  wrote:
>
> On 12/24/2016 09:59 PM, Chris Albertson wrote:
> > Read the little write up at the Mesa site about cable length.   They
> > claim ribbon cable is the worst and to only use it for very short
> > runs, 2 or 3 feet at most. They suggest using "real" parallel
> > cables made with twisted pairs and shielding for longer runs.  Using
> > one of their fancy IEEE cables you can go up to 25 or 30 feet, half
> > that with a normal round cable and half that again with ribbon
> > cable.
>
> You are right, ribbon cables are not very good at carrying signals over
> long cables. They will pick up too much noise if not shielded and suffer
> often from significant cross-talk if too long.
>
> The "standard" old-school printer cables (the round ones) are often
> shielded and twisted pair, which are actually quite good.


You have to be a little careful.   Most round cables you buy today say
"IEEE 1284" and these are the ones that allow data to go up to 30 feet
at up to about 2MHz.   But this assume good driver/buffers and old
style 74xx logic chips.The really old cables or those you make
yourself are good for maybe 1/2 these specs.   But IEEE 1284 is so old
almost anything sold as a "parallel printer cable" will be made to
this spec.But not so for old "junk drawer" parts.  So there is
"old school" and "really old school" you have to check what you have

I would start by testing with signals below the KHz range.  Maybe 100
steps per second on one axis.

-- 

Chris Albertson
Redondo Beach, California

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Gene Heskett 
On Saturday 24 December 2016 16:44:53 Bertho Stultiens wrote:

> On 12/24/2016 09:59 PM, Chris Albertson wrote:
> > Read the little write up at the Mesa site about cable length.   They
> > claim ribbon cable is the worst and to only use it for very short
> > runs, 2 or 3 feet at most. They suggest using "real" parallel
> > cables made with twisted pairs and shielding for longer runs.  Using
> > one of their fancy IEEE cables you can go up to 25 or 30 feet, half
> > that with a normal round cable and half that again with ribbon
> > cable.
>
> You are right, ribbon cables are not very good at carrying signals
> over long cables. They will pick up too much noise if not shielded and
> suffer often from significant cross-talk if too long.
>
> The "standard" old-school printer cables (the round ones) are often
> shielded and twisted pair, which are actually quite good.
>
> > For over 30 feet use some kind of differential signaling or fiber.
>
> Differential signaling or fiber is of course better, but very much
> more expensive. You will also need to convert the signals on each end.
>
> > There is nothing inherently bad about ribbon cable.  It is more
> > about how it is driven.  It works well as a 50 ohm transition line
> > if you terminate it at each end.  The old SCSI disk drives did that.
> >But there is an upper limit on how fast you can push data down a
> > parallel cable. This is why all the really fast computer interfaces
> > are now serial
>
> The impedance of cables is specific for each cable. You can often get
> them with quite different specifications (but look the same). This is
> where is gets a bit difficult. Most cabling for fast computer
> electronics is 100..120 Ohms. The lower 50 Ohm cabling is too power
> hungry(*) for digital logic (mainly in use in HF radio systems).
> Symmetrical termination is only beneficial if you need to guarantee no
> reflections in the cable, but that is not a requirement if you have a
> signal only going in one direction.
>
> Digital output buffers are generally made with low output impedance
> (0.01...10 Ohms), where you make your adjustments using series
> resistors at the signal's originator (the driver).
>
> I agree that for fast comms you go to serial because it reduces
> cabling complexities. However, I have a feeling that we are not
> talking about signals surpassing 1..10MHz.

Yes we are. I just this instant got past the roadblock with an r-pi using 
the SPI interface. The cable is a 26 line ribbon, src terminated, and 
running at 30 megahertz over about a 8" total cable length.  The src 
terms are about an inch away from the gpio pins.

Needless to say, my ears hurt, the grin, after all the headache from 
beating my head on the wall, is that wide.

> > Your problem might be because you are doing to much at once.  Can
> > you get a one axis stepper motor to run slowly using GPIO and no
> > FPGA card?  Does that work reliably through multiple upgrades and
> > config changes or is it fragile?  Or even before that, can you
> > install and update Linux and compile kernels and instal new drivers
> > and run a web browsers and email and do upgrades and such reliably
> > before using  RPi3 as a machine controller.
>
> You are right that not too much must be tested at the same time. But,
> it reminds me of a caution I did not mention. The cable must be driven
> by actual /drivers/. FPGA outputs or the RPi GPIO pins are not
> suitable as cable drivers. You need to use something that can pack a
> punch, current wise, to get the signal energy into the cable and to
> re-absorb it when reflected.
>
> If you use FPGA outputs or a RPi GPIO directly, then you can expect
> problems with cabling from about 0.2m onwards. Cable capacitance will
> start to influence the signals and reflections are so fast that you
> may overload the output pin, which might even result in silicon
> latch-up problems (and subsequent crash).
>
> Interfacing from RPi or FPGA should preferably be done using buffers.
> The electronic inputs you are controlling are often not or marginally
> compatible with the digital output of the computer board.
>
> Fwiw, an old style printer port uses a 74xx245 (74xx244), where xx is
> LS (very old PCs) or HCT ("newer" versions). These are real bus
> drivers, which can handle the load (most of the time). The (V)LSI
> printer-port chips in modern computers, just before the printer port
> was abandoned, may not have a very good output drivers.
>
>
>
> (*) This relates to the maximum power transfer theorem.


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)
Genes Web page 

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Bertho Stultiens 
On 12/24/2016 09:59 PM, Chris Albertson wrote:
> Read the little write up at the Mesa site about cable length.   They
> claim ribbon cable is the worst and to only use it for very short
> runs, 2 or 3 feet at most. They suggest using "real" parallel
> cables made with twisted pairs and shielding for longer runs.  Using
> one of their fancy IEEE cables you can go up to 25 or 30 feet, half
> that with a normal round cable and half that again with ribbon
> cable.

You are right, ribbon cables are not very good at carrying signals over
long cables. They will pick up too much noise if not shielded and suffer
often from significant cross-talk if too long.

The "standard" old-school printer cables (the round ones) are often
shielded and twisted pair, which are actually quite good.


> For over 30 feet use some kind of differential signaling or fiber.

Differential signaling or fiber is of course better, but very much more
expensive. You will also need to convert the signals on each end.


> There is nothing inherently bad about ribbon cable.  It is more about how
> it is driven.  It works well as a 50 ohm transition line if you terminate
> it at each end.  The old SCSI disk drives did that.But there is an
> upper limit on how fast you can push data down a parallel cable. This is
> why all the really fast computer interfaces are now serial

The impedance of cables is specific for each cable. You can often get
them with quite different specifications (but look the same). This is
where is gets a bit difficult. Most cabling for fast computer
electronics is 100..120 Ohms. The lower 50 Ohm cabling is too power
hungry(*) for digital logic (mainly in use in HF radio systems).
Symmetrical termination is only beneficial if you need to guarantee no
reflections in the cable, but that is not a requirement if you have a
signal only going in one direction.

Digital output buffers are generally made with low output impedance
(0.01...10 Ohms), where you make your adjustments using series resistors
at the signal's originator (the driver).

I agree that for fast comms you go to serial because it reduces cabling
complexities. However, I have a feeling that we are not talking about
signals surpassing 1..10MHz.


> Your problem might be because you are doing to much at once.  Can you get a
> one axis stepper motor to run slowly using GPIO and no FPGA card?  Does
> that work reliably through multiple upgrades and config changes or is it
> fragile?  Or even before that, can you install and update Linux and compile
> kernels and instal new drivers and run a web browsers and email and do
> upgrades and such reliably before using  RPi3 as a machine controller.

You are right that not too much must be tested at the same time. But, it
reminds me of a caution I did not mention. The cable must be driven by
actual /drivers/. FPGA outputs or the RPi GPIO pins are not suitable as
cable drivers. You need to use something that can pack a punch, current
wise, to get the signal energy into the cable and to re-absorb it when
reflected.

If you use FPGA outputs or a RPi GPIO directly, then you can expect
problems with cabling from about 0.2m onwards. Cable capacitance will
start to influence the signals and reflections are so fast that you may
overload the output pin, which might even result in silicon latch-up
problems (and subsequent crash).

Interfacing from RPi or FPGA should preferably be done using buffers.
The electronic inputs you are controlling are often not or marginally
compatible with the digital output of the computer board.

Fwiw, an old style printer port uses a 74xx245 (74xx244), where xx is LS
(very old PCs) or HCT ("newer" versions). These are real bus drivers,
which can handle the load (most of the time). The (V)LSI printer-port
chips in modern computers, just before the printer port was abandoned,
may not have a very good output drivers.



(*) This relates to the maximum power transfer theorem.

-- 
Greetings Bertho

(disclaimers are disclaimed)

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Chris Albertson 
Read the little write up at the Mesa site about cable length.   They claim
ribbon cable is the worst and to only use it for very short runs, 2 or 3
feet at most. They suggest using "real" parallel cables made with
twisted pairs and shielding for longer runs.  Using one of their fancy IEEE
cables you can go up to 25 or 30 feet, half that with a normal round cable
and half that again with ribbon cable.

For over 30 feet use some kind of differential signaling or fiber.

There is nothing inherently bad about ribbon cable.  It is more about how
it is driven.  It works well as a 50 ohm transition line if you terminate
it at each end.  The old SCSI disk drives did that.But there is an
upper limit on how fast you can push data down a parallel cable. This is
why all the really fast computer interfaces are now serial

Your problem might be because you are doing to much at once.  Can you get a
one axis stepper motor to run slowly using GPIO and no FPGA card?  Does
that work reliably through multiple upgrades and config changes or is it
fragile?  Or even before that, can you install and update Linux and compile
kernels and instal new drivers and run a web browsers and email and do
upgrades and such reliably before using  RPi3 as a machine controller.

On Sat, Dec 24, 2016 at 4:20 AM, Gene Heskett  wrote:

> Greetings folks;
>
> This is a heck of a thing to throw out on Christmas Eve.
>
> I am about burned out on trying to make the raspi 3b work.
>
> I saw it work once, for about 2 days, then an update blew it up by
> replacing the rt kernel, and it has not worked since. In the sd cards
> I've made since, probably 8 or more, following the recipe given, the
> halrun;halc md loadrt hostmot2;loadrt hm2_rpspi test procedure works
> perfectly.  But linuxcnc refuses to load that hm2_rpspi driver.
>
> Mr. Martinjack built me an image and sent me the link to it. No gui, so
> testing would have to be done over an ssh -Y login.  He, I believe went
> to quite some effort to do that, and I assume that it worked on his
> raspi-3b. But when I wrote it to a zeroed 32Gb card, expanded the
> filesystem on the first boot, then configured the networking in static
> mode, making it immutable as I went so whatever raspian uses in place of
> network-mangler can't tear it down on the next boot, the result can't do
> the halrun test.
> ---
> pi@raspberrypi:~ $ halrun
> halcmd: loadrt hostmot2
> Note: Using POSIX realtime
> hm2: loading Mesa HostMot2 driver version 0.15
> halcmd: loadrt hm2_rpspi
> Unknown board: HOST
> hm2_rpspi: rtapi_app_main: Operation not permitted (-1)
> :2: waitpid failed /usr/bin/rtapi_app hm2_rpspi
> :2: /usr/bin/rtapi_app exited without becoming ready
> :2: insmod for hm2_rpspi failed, returned -1
> -
> which is the same failure I get when trying to start linuxcnc on one of
> my builds.
>
> And this is the 2nd pi-3b I've put in.
>
> Does my use of a 32GB card have anything to do with this?
> Does my use of the full jessie install instead of the jessie-lite have
> anything to do with this? I can try that once.
>
> If that fails, I'll quit beating my head with a hammer and reset this
> 7i90 to an epp interface and go back to an x86 computer to drive it, but
> that brings up the next $64K question.  The big old Dell I have to drive
> it with isn't swarf proof by any means, and it will take at least 6 or
> even 8 feet of ribbon cable to get it far enough away from the swarf to
> be safe from flying chips.  Can I use a ribbon cable that long with good
> results?  The man page says it could be a problem but doesn't say how
> long is too long.  And I've no clue if the parport on this old Dell can
> be made epp-1.9 compliant.  TBD I guess.
>
> Thanks everybody. And have a Merry Christmas.
>
> 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)
> Genes Web page 
>
> 
> --
> Developer Access Program for Intel Xeon Phi Processors
> Access to Intel Xeon Phi processor-based developer platforms.
> With one year of Intel Parallel Studio XE.
> Training and support from Colfax.
> Order your platform today.http://sdm.link/intel
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>



-- 

Chris Albertson
Redondo Beach, California
--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Gene Heskett 
On Saturday 24 December 2016 12:40:43 Bertho Stultiens wrote:

> On 12/24/2016 01:20 PM, Gene Heskett wrote:
> > If that fails, I'll quit beating my head with a hammer and reset
> > this 7i90 to an epp interface and go back to an x86 computer to
> > drive it, but that brings up the next $64K question.  The big old
> > Dell I have to drive it with isn't swarf proof by any means, and it
> > will take at least 6 or even 8 feet of ribbon cable to get it far
> > enough away from the swarf to be safe from flying chips.  Can I use
> > a ribbon cable that long with good results?  The man page says it
> > could be a problem but doesn't say how long is too long.  And I've
> > no clue if the parport on this old Dell can be made epp-1.9
> > compliant.  TBD I guess.
>
> The achievable length of the cable is usually determined by the cable
> loss and the impedance matching of the cable.
>
> In principle, you can roll out 25m of parallel port cable if you
> ensure that firstly, the drive power is sufficient to overcome the
> capacitive load of the cable and secondly, that the cable-impedance is
> matched either with driver-side series resistors or symmetrical
> termination on each side. (*)
>
> The drive power of most "old-style" parallel ports is enough to drive
> 10m of cable. However, the reflections are significant and interfere
> with higher frequency signaling (step-signals are fast enough to
> suffer).
>
> The cable impedance is usually around 100 Ohms (maybe 120 for some).
> Thus, inserting a 100..120 Ohm series-resistor on each output driver,
> just before entering the cable (ideally at the driver output pins of
> the driver chip), should be a nice enough match for most cases and
> uses. Just be sure that you identify the correct side of the cable
> where to insert the resistor. It must be done on the drive-side to be
> effective. If you have bidirectional communication on a wire, then it
> becomes a bit more difficult. But that usually does not happen on most
> EPP setups and the inputs and outputs are perfectly defined and
> constant.
>
> (*) I am ignoring common-mode and ground problems here, just as
> shielding. If your environment is balanced enough and not EMI
> infested, then you should not see too many problems.

Thats encouraging Bertho. If I can beat the parport into epp,v1.9 mode, 
we'll try 10 feet.  EMI could be a problem as the power goes up to the 
VFD, and the VFD drive comes back, thru the same length non-shielded 
plastic bx. That isn't going to be common with the ribbon cable, nor 
with the isolated 4 wire from the spinx1 to the vfd.

I won't know for sure till its been tried. :) or :(  But this is 
Christmas Eve. So almost nothing will be done till Monday.

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)
Genes Web page 

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Bertho Stultiens 
On 12/24/2016 01:20 PM, Gene Heskett wrote:
> If that fails, I'll quit beating my head with a hammer and reset this 
> 7i90 to an epp interface and go back to an x86 computer to drive it, but 
> that brings up the next $64K question.  The big old Dell I have to drive 
> it with isn't swarf proof by any means, and it will take at least 6 or 
> even 8 feet of ribbon cable to get it far enough away from the swarf to 
> be safe from flying chips.  Can I use a ribbon cable that long with good 
> results?  The man page says it could be a problem but doesn't say how 
> long is too long.  And I've no clue if the parport on this old Dell can 
> be made epp-1.9 compliant.  TBD I guess. 

The achievable length of the cable is usually determined by the cable
loss and the impedance matching of the cable.

In principle, you can roll out 25m of parallel port cable if you ensure
that firstly, the drive power is sufficient to overcome the capacitive
load of the cable and secondly, that the cable-impedance is matched
either with driver-side series resistors or symmetrical termination on
each side. (*)

The drive power of most "old-style" parallel ports is enough to drive
10m of cable. However, the reflections are significant and interfere
with higher frequency signaling (step-signals are fast enough to suffer).

The cable impedance is usually around 100 Ohms (maybe 120 for some).
Thus, inserting a 100..120 Ohm series-resistor on each output driver,
just before entering the cable (ideally at the driver output pins of the
driver chip), should be a nice enough match for most cases and uses.
Just be sure that you identify the correct side of the cable where to
insert the resistor. It must be done on the drive-side to be effective.
If you have bidirectional communication on a wire, then it becomes a bit
more difficult. But that usually does not happen on most EPP setups and
the inputs and outputs are perfectly defined and constant.

(*) I am ignoring common-mode and ground problems here, just as
shielding. If your environment is balanced enough and not EMI infested,
then you should not see too many problems.

-- 
Greetings Bertho

(disclaimers are disclaimed)

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread John Thornton 
Merry Christmas Gene.

JT


On 12/24/2016 9:58 AM, Gene Heskett wrote:
> On Saturday 24 December 2016 09:41:48 John Thornton wrote:
>
>> Hi Gene,
>>
>> You could use this:
>>
>> http://mesaus.com/index.php?route=product/product=71_id=5
>> 9
>>
>> with this:
>>
>> http://mesaus.com/index.php?route=product/product=71_id=7
>> 0
>>
>> To get 7' between the 7i90 and the PC.
>>
>> JT
> The 5i25 doesn't have a bit file that can drive the 7i90 in epp mode
> according to Peter. So this cable would be from the parport on the dell,
> to the 7i90. I'll find out as I have a box of cable and some connectors.
>
> Thanks John. Have a Merry Christmas.
>
> Cheers, Gene Heskett


--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Gene Heskett 
On Saturday 24 December 2016 09:41:48 John Thornton wrote:

> Hi Gene,
>
> You could use this:
>
> http://mesaus.com/index.php?route=product/product=71_id=5
>9
>
> with this:
>
> http://mesaus.com/index.php?route=product/product=71_id=7
>0
>
> To get 7' between the 7i90 and the PC.
>
> JT

The 5i25 doesn't have a bit file that can drive the 7i90 in epp mode 
according to Peter. So this cable would be from the parport on the dell, 
to the 7i90. I'll find out as I have a box of cable and some connectors.

Thanks John. Have a Merry Christmas.

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)
Genes Web page 

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread John Thornton 
Hi Gene,

You could use this:

http://mesaus.com/index.php?route=product/product=71_id=59

with this:

http://mesaus.com/index.php?route=product/product=71_id=70

To get 7' between the 7i90 and the PC.

JT


On 12/24/2016 6:20 AM, Gene Heskett wrote:
> Greetings folks;
>
> This is a heck of a thing to throw out on Christmas Eve.
>
> I am about burned out on trying to make the raspi 3b work.
>
> I saw it work once, for about 2 days, then an update blew it up by
> replacing the rt kernel, and it has not worked since. In the sd cards
> I've made since, probably 8 or more, following the recipe given, the
> halrun;halc md loadrt hostmot2;loadrt hm2_rpspi test procedure works
> perfectly.  But linuxcnc refuses to load that hm2_rpspi driver.
>
> Mr. Martinjack built me an image and sent me the link to it. No gui, so
> testing would have to be done over an ssh -Y login.  He, I believe went
> to quite some effort to do that, and I assume that it worked on his
> raspi-3b. But when I wrote it to a zeroed 32Gb card, expanded the
> filesystem on the first boot, then configured the networking in static
> mode, making it immutable as I went so whatever raspian uses in place of
> network-mangler can't tear it down on the next boot, the result can't do
> the halrun test.
> ---
> pi@raspberrypi:~ $ halrun
> halcmd: loadrt hostmot2
> Note: Using POSIX realtime
> hm2: loading Mesa HostMot2 driver version 0.15
> halcmd: loadrt hm2_rpspi
> Unknown board: HOST
> hm2_rpspi: rtapi_app_main: Operation not permitted (-1)
> :2: waitpid failed /usr/bin/rtapi_app hm2_rpspi
> :2: /usr/bin/rtapi_app exited without becoming ready
> :2: insmod for hm2_rpspi failed, returned -1
> -
> which is the same failure I get when trying to start linuxcnc on one of
> my builds.
>
> And this is the 2nd pi-3b I've put in.
>
> Does my use of a 32GB card have anything to do with this?
> Does my use of the full jessie install instead of the jessie-lite have
> anything to do with this? I can try that once.
>
> If that fails, I'll quit beating my head with a hammer and reset this
> 7i90 to an epp interface and go back to an x86 computer to drive it, but
> that brings up the next $64K question.  The big old Dell I have to drive
> it with isn't swarf proof by any means, and it will take at least 6 or
> even 8 feet of ribbon cable to get it far enough away from the swarf to
> be safe from flying chips.  Can I use a ribbon cable that long with good
> results?  The man page says it could be a problem but doesn't say how
> long is too long.  And I've no clue if the parport on this old Dell can
> be made epp-1.9 compliant.  TBD I guess.
>
> Thanks everybody. And have a Merry Christmas.
>
> Cheers, Gene Heskett


--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

[Emc-users] Allowable length of db25 interconnect cabling to talk to an epp version of a 7i90?

2016-12-24 Thread Gene Heskett 
Greetings folks;

This is a heck of a thing to throw out on Christmas Eve.

I am about burned out on trying to make the raspi 3b work.

I saw it work once, for about 2 days, then an update blew it up by 
replacing the rt kernel, and it has not worked since. In the sd cards 
I've made since, probably 8 or more, following the recipe given, the 
halrun;halc md loadrt hostmot2;loadrt hm2_rpspi test procedure works 
perfectly.  But linuxcnc refuses to load that hm2_rpspi driver.

Mr. Martinjack built me an image and sent me the link to it. No gui, so 
testing would have to be done over an ssh -Y login.  He, I believe went 
to quite some effort to do that, and I assume that it worked on his 
raspi-3b. But when I wrote it to a zeroed 32Gb card, expanded the 
filesystem on the first boot, then configured the networking in static 
mode, making it immutable as I went so whatever raspian uses in place of 
network-mangler can't tear it down on the next boot, the result can't do 
the halrun test.
---
pi@raspberrypi:~ $ halrun
halcmd: loadrt hostmot2
Note: Using POSIX realtime
hm2: loading Mesa HostMot2 driver version 0.15
halcmd: loadrt hm2_rpspi
Unknown board: HOST
hm2_rpspi: rtapi_app_main: Operation not permitted (-1)
:2: waitpid failed /usr/bin/rtapi_app hm2_rpspi
:2: /usr/bin/rtapi_app exited without becoming ready
:2: insmod for hm2_rpspi failed, returned -1
-
which is the same failure I get when trying to start linuxcnc on one of 
my builds.

And this is the 2nd pi-3b I've put in.

Does my use of a 32GB card have anything to do with this?
Does my use of the full jessie install instead of the jessie-lite have 
anything to do with this? I can try that once.

If that fails, I'll quit beating my head with a hammer and reset this 
7i90 to an epp interface and go back to an x86 computer to drive it, but 
that brings up the next $64K question.  The big old Dell I have to drive 
it with isn't swarf proof by any means, and it will take at least 6 or 
even 8 feet of ribbon cable to get it far enough away from the swarf to 
be safe from flying chips.  Can I use a ribbon cable that long with good 
results?  The man page says it could be a problem but doesn't say how 
long is too long.  And I've no clue if the parport on this old Dell can 
be made epp-1.9 compliant.  TBD I guess. 

Thanks everybody. And have a Merry Christmas.

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)
Genes Web page 

--
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users