Problems

[ViperTX]

Oscilloscope......now for a question.....are these 100 volt servos...like in DC Servos.....??

[HillBilly]

One thing to check will be your armature to groung resistance. Servo motors that have been in use for a while can built up brush dust and conduct (see attached pic.).

Darek

[vebers]

Thanks for all of your help and advice. I think (very hopefull) that we have the problem solved. What I ended up having to do was leave the sheild on both ends of the motor cable all the way from the motor to the board. I stripped less than a half an inch back to get a couple of ring terminal on it. This seems to have made a world of diffrence in this machines behavior. I am still occasionally getting some funky stuff when I tune, but the encoder readings have quit jumping and I am no longer getting communication errors. The servo's are 100 VDC. I am going to try hooking the other two axis up and hopefully my luck holds. I will let everyong know. I also noticed that it works best with the sheild drain not connected on either end and the motor case ground not connected. I hope this thread can save someone some time putting together a system like mine in the future. Thanks for the help.

Vince

[HillBilly]

Originally Posted by vebers I also noticed that it works best with the sheild drain not connected on either end and the motor case ground not connected. Vince

That sounds like a sure sign of armature current leaking to ground and returning through the sheild. If this is the problem a regular ohm meter should see it, a megar would be better.

Darek

[miljnor]

Not only what hillbilly said, but you might as well not use sheilded wire at all if your not grounding one end.

Without a return path for the voltage created in the shield it doesn't really do anything!

[dpaulson]

You are using the sheild as a common ground. I would suggest running a single wire as a ground and disconnecting one side of the shield drain and using it to sheild noise.

[vebers]

I would Like to thank all of you for your contributions, your advice and encouragment kept me from throwing the whole thing against the wall. To update you the machine is making money. A combination of many of the ideas you all provided helped get it that way.

Thanks

Vince Ebers
MVM Precision Machine

[miljnor]

good job man and glad to hear it!