Hi
I'm having trouble tuning the Z axis servo on my Matsuura MC500v retrofit. Ive read through the manual and done enough research to understand the PID loop. I've tuned the X and Y axis fairly well with the help of the auto tuning function and manual tweaking. Something just isn't right with the Z axis though. The servos are the same on all three axis, but the gearing between the servo and the ball screw is a little lower on the Z axis to allow for more torque. The encoders are built into the back of the servos before the gearing. When I attempt to auto tune, I end up with a Proportional gain around 600 and an integral gain around 200 while the P gain on my x and y axis is around 20000. Also, the axis should be capable of around 400 inches per minute. The fastest I can get the thing to move is 40 inches per minute. If I attempt to set a max speed of 400, the machine will move at 40 inches per minute until a following error is triggered.
My thoughts are that there is something wrong with the drive. If I unplug the tach input from the encoder to the servo drive ( yaskawa cpcr-mr-052-nb), the servo seems to break free and will oscillate closer to 400 inches per minute for a moment before a following error is triggered in mach.
This is my first time tuning a machine with servos rather than steppers, so any and all help would be appreciated. Thanks!
Jonathon