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Submitted by lgulyas on Wed, 05/03/2017 - 05:34

Hi,
I have an old DCM 2050 microcontroller connected to a Yokogawa UR1BG3 drive, which is powering a Yokogawa DR1B brushless servo motor, which is rotating a 0,5T hemisphere. The drive's A+/A-, B+/B-, z-pulse signal is connected to the microcontroller and the microcontroller commands the velocity over it's analog output for the drive.

Lately we were experiencing some issues. I can't fine tune the motor to follow the commanded position precisely. In the WSDK software I'am scoping the motor's position error and I get small position error spikes (+/-150 count), while tring to rotate the motor at a fixed speed. First I thought it's the encoder in the motor but after replacing the motor, the issue still exist. I'am tring to find out if there is an issue with the DCM 2050 or with the drive. When manualy turning the motor I can see the position change in the WSDK software, if the motor is in stady position the position doesn't jumping around. There is no mechanical issue in the system.
Since the drive is not manufactured by Yokogawa anymore we cant change the driver for testing.
What if the controller's analog velocity command is not precis (due to noise) or it's not been able to convert the A+/A-, B+/B- signal to position information correctly? Is there a method to rule out the drive or the Galil?
Is there any waveform's for the expected A+/A-, B+/B-, z-pulse input signal or the analog output velocity command signal?

Best regards,

Laszlo

Comments 1

Coryl on 05/16/2017 - 09:29

Hello Laszlo,

This issue looks more complex than can be solved over the forum.

Please contact me directly at cory l at galil dot com or call us at 916-626-0101 to discuss more in-depth.

Thank you,

Cory D. Lent