How to go back to a previous version of NI Motion

[JWfee]

Has anyone tried going back to an older version of NI Motion?  Specifically I loaded labview 8.5 and NI Motion 7.6 on to my computer after having run Labview 6.1 and NI Motion 5.1.1 successfully for seven year.  The newer version is not compatible with my system and will not run.  I've loaded the old system on a completely different hard drive and tried to get the system back the way it was.  My motor appears to be out of tune and will not run.  I note that both the new .xml file and the firmware files are bigger in the 7.6 version.  I've tried padding the 5.1.1 firmware files with NULL characters but that didn't help.  I suspect that some part of the new .xml file is being left on the board when I write the old one back.  Anyone know a work around?

Jim Fee

[Michelle_N]

Hi Jim,

What is happening when you try to return the firmware to NI-Motion 5.1.1? Are you getting an error or does it seemingly load fine and you are not able to initialize? I do know what putting NULL characters will do with the firmware and do not suggest this.

Are you interested in going to the new LabVIEW and Motion if you are able to get this working?

[JWfee]

What I'm interested in is getting this working LAST MONTH!!!  I'm a research engineer in a children's hospital I have research subjects waiting on this thing.  We've had people from NI and the third party vendor in here and neither has made much progress.  The NI people put the amplifier in a different mode and got the motor to "find home" sometimes, but its not reliable enough to put a subject anywhere near it.  I've had our third party vendor in here and they feel certain that everything is back the way it was on a new hard drive and still the motor oscillates about the home position.  NI has lent me another board, I put that in about an hour ago, and that still behaves the same way, oscillations about the home position.  We are clearly missing something....but WHAT?????????

Jim Fee

[Michelle_N]

Jim,

This sounds a lot like an issue with pull-in moves.

"Pull-in: When stepper motors are run in closed-loop mode, the encoder feedback is used to verify the position of an axis when the motion ends. The motion controller then commands the axis to do a final move so that it is at the specified target position."

If the number of pull-in moves is set extremely high I can see this causing what you are seeing.

Can you give me more information on your setup and when you see this oscillation. I'm assuming it is only when you tell the motor to find home.

[JWfee]

Thanks Michelle

I wish it were that  simple, first its not a stepper motor its a servo motor and second these oscilation happen on ANY move, even one made with MAX.

For whatever its worth  Its a Kollmorgan Goldline XT Brushless Servomotor w/ single speed resolver # MT 506 AI R1C1.

The Amplifier controller is also Kollmorgan Servostar 600 #S61001.

Jim Fee

[Michelle_N]

Jim,

Can you tell me what the step response for this motor looks like in MAX? What do you get for settling time, rise time, peak time, max overshoot? And what do you have step length and samples set to? Does this also oscillate?

How has tuning affected the oscillations? I know you have most likely gone through and checked the tuning on this servo but I want to verify this.

Also, what National Instruments PCI/PXI controller card are you using?

[JWfee]

Step responce MY FOOT!  I can't get that far.  All I have to do is enable the drive from a dead calm stop and the motor begins to oscilate at ever increasing amplitude till I hit the kill switch.

I have not tried to retune the system as yet because it MAKES NO SENSE to me to do so...why after 7 years of operation
should the tuning parameters suddenly be wrong?

The controller card is a PCI 7344

Jim Fee

[AnalogKid2DigitalMan]

FWIW:

Recently I had a brushless servo system that had been working well for many years- one day the axis started buzzing and vibrating. I figured it was out of tune, but could not retune it back to smooth operation. Turned out the servo drive amp had a failure. Replacing the amp solved the issue.

Has a new amp been tried and or motor/resolver combination?