change analog output voltage

[Karl_T]

I've been working one this one a little every day for several days now. I'm out of ideas.

I have my VFD on the spindle all set up and running nicely. For speed control, I debugged it with a pot and varied the input voltage from 0 - 10 volts. Everything is just right.

I then disconnected the pot leads and put the signal ground* on the Galil 1900 board ground pin 17. Then the signal wire on pin 26 MOCMDZ.

*(also tried ISO ground pin 35 - it floats up to 3.8 volt and spindle won't turn)

Now I can only get the spindle to run at one speed. Correct for 3.8 volts that I read at pin 26. This pin goes from 0 to 3.8 volts as soon as I power the computer and I can't get it to change.

I've tried almost too many things to list: TEST SPINDLE, ANALOG3 ##;OUT (## everything from 0 to 10), hooked up a pot for speed on AN2 - set up \74 for speed control, all sorts of setup changes. I get nothing of use in logfile.fil


At this point, I need to prove to myself that the board is not defective. Then start over on software setup. I don't know native galil at all. I'm thinking I should try loading smartterminal and commanding through Galil. Any ideas?

Karl

[Al_The_Man]

I would run DMCTerminal and see if it works with native commands, the voltage should be 0v not 3.8 at power up. Make sure the 100 pin cable is pushed right in both ends as this has been known to cause open ground return.
Make sure you are set up for analog and not steppers with the board jumpers and also interogate using the MT command to see what type of motors are set up in the card.
To test the analog output, disconnect it from the drive and then use OF commands to set various output voltages (verify with TT) and then physically measure with a DMM. You should have a full range of roughly +/-10v. If these voltages differ, then the possibly failure could be with the analog buffer switch (ADG202AKN or MAX332 chip) located at U1 on the ICM unit. You should also make sure that TL is set to 9.9982
Set TL Z to zero should zero the analog out for Z.
Other commands that should null the analog out is SH (Servo Here) MO (motor off) and RS (reset).
Make sure you are using the main board GND and not ISO ground for the command.
I would also zero the KD,KP and KI commands for that axis.
Al.

[Karl_T]

Wow, thanks for the great helpful post. This NG wouldn't be the same without you. You truly are Al, THE MAN.

Karl

[Karl_T]

Follow up.

I had to change out the whole 1900 ICM unit. Just changing the IC mentioned didn't help.

I'm totally clueless as to why the ICM would do this, but glad the problem is solved and I can move on.

Karl


Karl

[murphy625]

I was going to jump in earlier before Al because I had a situation exactly like yours.

My problem turned out to be incorrect grounding procedures. The MoCmd was floating to around +2 volts.. More than enough to screw up the servo drive.

Turned out my grounding set up was screwy. On advice, (some from AL), I went to a "star" configuration which seemed to fix the problem. (mostly).. Then I discovered my partner did not install a grounding rod in his electrical box. (dont ask as I have worn out my nerves on him)..

My problems all went back to bad grounds..

Glad you fixed yours.

Murphy