Viper 200 Tuning Question, Act like an Amp only?

[slimneill]

We went with:
-Viper 200 DC Servo Motor Control
-KFlop Motion Control Board from Dynomotion
-2000 CPR E6 Optical Encoder from US Digital
-Baldor Motor (taken out of original CNC machine)
-Power Supply: 165V DC

Baldor 5D42-30-A19-A40
Max Current: 15.7A continuous
Max Current: 73A peak
Torque Stall: 50 lb-in continuous
Max Speed: 3000RPM
Max V: 180DC


The way I have it set up currently is that the Viper accepts the Encoder signal and closes the position loop itself. The KFlop currently only sends the step and direction from the PC to the vipers which power the Baldor Motors. I know the Kflop can take the encoder signal and close the loop that way too but I’m not sure if the Viper can function strictly as an amplifier.


Everything is currently set up on the work bench. I have realized that these motors are big powerful units, which is making the tuning sequence with the Viper very trial and error and difficult to optimize. Have you ever try to upset the shaft of a 50lb-in servo motor working against you? It barely budges while trying with all my might.

According do the Viper manual you upset the motor and then adjust the parameters so that it returns to steady state as quickly and smoothly as possible with out continuous oscillation. The problem is that, we can only budge it 3 to 5 degrees and then is returns to it’s park position right away with no visible oscillation, only a slight hum and clicking sound. This is telling me that the servo is constantly trying to fight it’s way back to the true home position even after being a rest for a min or so. We found that applying a hand to the shaft to dampen the shafts motion helps it settle quicker but it doesn’t stay completely still for long. Taking a stethoscope to the side of the motor, you can hear it clicking back and forth as it tries to find rest and once it does it will start clicking and self adjusting randomly many times over the course of a minute, for as long as it is turned on.

• Is there a way to allow the Viper to function without requiring the step and direction?

• I’m finding it difficult to fine tune the viper and the KFlop has a very use friendly interface for fine tuning the servos. Is there anything similar for the Viper?

• Does the Viper have a deadband setting that will eliminate the constant clicking?

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[TomKerekes]

If you connected the encoder signals back to KFLOP (in parallel to the Amplifier) you could use our Step Response Screen to make plots and observe performance.

The other benefit of doing this is that KFLOP could detect following errors and after a fault the commanded position could be reset to the current encoder position without requiring a re-home.

Regards

[Larken]

When the clicking is going on, are there any errors showing on the drive ? Is the motor holding in both directions?
No, the viper can't act as an Amp only
Can you use the Kflop to jog the motor back and forth to allow you to get a responce ?
or Can you put a 6" or larger pulley on the shaft to help with tuning?

Yes there is a deadband friction command. its the h (hysterisis) setting


Thanks Tom for your input, you make a nice product.

[TomKerekes]

Can you use the Kflop to jog the motor back and forth to allow you to get a response ?

Yes, you can use the Step Reponse Screen to do a "Move" back and forth at the specified Size, Velocity, Acceleration, and Jerk.

Larken, as are yours.

Regards