PCI 7344 behaving erratically, random servo movements

[henradrie]

I'm using a PCI 7344 to control a 3 axis test stand. Today when I initialized it with out modifiying any settings it didn't work, just kept moving servos randomly even when controlled by MAX and a movement script. Even the kill command didn't work. I checked for disconnected wires but nothing was out of place from the last time I used the system.

The servos of all axes acted strangely. The current position, target position and following error remained at zero even though the motors were spinning. On one axis the MAX software would show the current position increasing and random velocity values while the target position and following error remained at zero. 

Something went wrong and I don't know how to fix it this time. Does anybody have any idea what to do? Ever since I was put on this project I have never enjoyed working with NI-MAX or the PCI-7344. It seems that I spend more time fixing it than using it for experiments. 

[aflojo]

Hi henradrie,

That is wierd behavior you are seeing. Are you running the script in the 1D interactive in MAX, 2D interactive in MAX or are you using the NI Motion assistant? Do you normally interact with the motor just in MAX or in LabVIEW as well? 

Do you see this same behavior after power cycling the system?

What drive are you using? What version of NI-Motion do you have on your computer? You had said there were not errors during any of this behavior, is this correct? 

[aflojo]

Hi Henradrie,

That is wierd behavior you are seeing. Are you running the script in the 1D interactive in MAX, 2D interactive in MAX or are you using the NI Motion assistant? Do you normally interact with the motor just in MAX or in LabVIEW as well? 

Do you see this same behavior after power cycling the system?

What drive are you using? What version of NI-Motion do you have on your computer? You had said there were not errors during any of this behavior, is this correct? 

[Highland_Controls]

Measure the voltage at the torque command. You will probably need a scope to properly check this.  Make sure the motion commands are not coming from somewhere else(drive issue?).

I don't use NI Motion products.  There is a lot of room for improvement there.  I use other motion products that easily interface to LabVIEW(not as easily as NI stuff, though).

[henradrie · Accepted solution]

Turns out somebody disconnected the USB cable used to power the PCI 7344. Once I plugged that back in it worked well again.