Steps per revolution

[scrambled]

I am having a problem, and need some help.

For the X and A axis I am using Granite devices VSD-E serov drives, US digital 1250 encoders, and Thompson duratrue 5 to 1 gear boxes, and rack and pinion. The pinion is 1 inch in diameter.

The problem is that I keep getting following errors. I have the x and A slaved together in Mach, and for now I have the steps per rev. set at 3700.

The faults occure at higher speeds (400 + ipm) but no problems at lower speeds.


My question is can I or is it possible that the steps per rev are different per axis?

Should one be set at 3700 and the other at 3725 or do they have to be set the same since they are slaved together?

I have the Granite Devices step multiplyer set to 3 to 1.


any other suggestions?




Steve

[Torchhead]

YOu do not have to have both motors tuned EXACTLY the same. I calibated each side of my gantry and discovered the A side was a few steps per inch different.

The other day my A started getting off. I have separate home switches and normally you cannot tell which trips first (dead on) but I started to notice that A was always lagging behind Y and would always trip a little later. I crawled all over the machine, tightening all of the pulleys, pinons and anything else I could find (most common problems are mechanical). I was about ready to start tearing things down when my lead tech came over opened motor tuning and said "why is the acceleration on A so much lower than Y?". Making them the same fixed the problem.

So you can tune them different but BE CAREFUL (:-)

Tom Caudle
www.CandCNC.com

[scrambled]

Thanks Tom


I changed the settings of each drive A and X to be identical in the drive tuning, and the problem is better


Steve