Ultra 3000 E20 error

[catfaneng]

We have been having alot a problems with our Ultra 3000 servo drives faulting out on E20 error. I was wanting to see if anyone else is having this problem. We are using a high res. encoder for feedback with the specified shielded cable. We have three different machines with this setup and have tried everything imaginable to resolve this issue but have been unsuccesful. One machine has the encoder cable in conduit from motor to drive, two are in cable tray with only other shielded cables. One of the machines with the cable in tray does not have the issue but the other does. I can not find any difference in the two of them. We have tried it with shield grounded and ungrounded. All machines have the encoder cable spliced about 10 ft from the motor. This is done for quick changeout of damaged cable due to harsh environment. AB's solution is below: Changing out encoder/motor does not help.

E20
Motor Encoder State Error The motor encoder encountered an illegal transition.
• Replace the motor/encoder.
• Use shielded cables with twisted pair wires.
• Route the feedback away from potential noise sources.
• Check the system grounds.
• Verify that the unbuffered encoder signals are not subjected to EMI in the CN1 cable. Remove these signals from the CN1 cable if they are not being used.
• Verify that the motor has a high-frequency bond to the drive’s enclosure panel.
• Verify that any stage connected to the motor shaft (for example using a ball screw) has a high-frequency bond to the machine frame and the drive’s enclosure panel.

 

[itsmoked]

A scope is required. They generally promptly show what the issue is. Most of the noise issues are really actually pretty bad and the controllers handle most of it. So you get thousands or millions of noise events and only one, here or there, actually cause an obvious/detected problem. So when you hook up a scope you see them all. Then you can, in real time, see what your mitigation efforts produce.

I will also point out that often systems have a much higher bandwidth than is needed for the task at hand. {Much higher!} This trips up the system as it becomes more sensitive to noise than it would be otherwise. I have fixed these systems with judicious addition of capacitors which reduce the bandwidth with NO down side on the operational side. Again, stuff like this can be easily assessed only with a scope.

Keith Cress
kcress -

http://www.flaminsystems.com