Re: [CAD_CAM_EDM_DRO] Question regarding Tuning Servo motors

You are using the G340 with the rate multiplier. The problem may be that you have too high a setting of the rate multiplier which could cause the G340 to fault sooner.
Most gecko drives are properly set from the factory for the Gain and the Dampening. I generally set them for at 11:30 from the fully CCW position when looking at the back of the G340. I have set hundreds of motors this way and they work fine with very minor tweaking.
Other things to look at is that you may have the acceleration set way to high.
With those motors, I would take the current limiting trim box and turn it CW all the then back off 1/4 turn.

Dan Mauch
economical 3D scanner software and kits
low cost stepper and servo motors.
cases for Gecko drives
kits and assembled 3-4 axis drives
www.camtronics-cnc.com
www.seanet.com/~dmauch

----- Original Message -----
From: Preston Engebretson
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Thursday, January 01, 2009 10:38 AM
Subject: [CAD_CAM_EDM_DRO] Question regarding Tuning Servo motors


Hello Everyone,

Here's what we have:

3 Homeshopcnc Nema 34 850 oz/in 72 VDC servos with 250 count encoders.

These are mounted on the x, y, z axises of our Hurco cnc mill.

We are using Gecko 340's on a Lococnc BOB.

We have all of the belts to the ballscrews disconnected in case of a
run away...do not want to break anything, and will mount the limit
switches later.

When trying to tune the servos, there seems to be a very narrow range
for adjusting the Limit, Damp and Gain to be able to get the servos
to run without Faulting the Gecko.

My electronics engineer is thinking that the servos need to have a
load on them to tune properly and wants to hook up the belts to drive
the ballscrews...

We have had several runaways without the ballscrews hooked up and I'm
concerned...

What is the proper way to tune these servos?

Best Regards,

Preston





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