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Author Topic: erratic behavior on servo machine  (Read 8404 times)

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Re: erratic behavior on servo machine
« Reply #10 on: August 25, 2006, 12:16:35 PM »
Jerry if you have to much trouble mail me off list and I will help you with setting up the shielding
Fixing problems one post at a time ;)

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Re: erratic behavior on servo machine
« Reply #11 on: August 25, 2006, 12:18:22 PM »
Brian,
Yes thanks about the grounding, the shields are grounded at the control box only.


I have some 16/2 shielded wire, do you think changing the twisted pair would enable me to re-bundle signal and power lines? I run the servos at 70 V and seldom pull more than 2 amps.

Thanks,
Jerry
Re: erratic behavior on servo machine
« Reply #12 on: August 25, 2006, 12:20:06 PM »
I would hook the shield to the encoder ground of the gecko...
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: erratic behavior on servo machine
« Reply #13 on: August 25, 2006, 12:35:06 PM »
Brian,
The signal shield, Yes?
What about shielding the motor power leads? Think that'll help?
Jerry
Re: erratic behavior on servo machine
« Reply #14 on: August 25, 2006, 01:22:59 PM »
Okay, Final Wrap,
Put the shield wire in the Gecko "encoder minus" terminal, partially rebundled, changed indicator to .0001 unit.

Repeatability .00015 and that's probably in the indicator stand. the indicator is so sensitive it moves in a big wind. :-) :-) :-)

It appears that the ground connection had deteriorated over time!???

Jerry
Re: erratic behavior on servo machine
« Reply #15 on: August 25, 2006, 06:35:18 PM »
Good to hear you got it working again!
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: erratic behavior on servo machine
« Reply #16 on: October 29, 2006, 07:05:42 PM »
I have a Y axis running with ac servos at 600IPM, everything works perfectly, the repeatability is dead on, except it seems like I loose steps at power down which results in a descrepancy of a consistant 0.0005 inches of loss.  It is very small and not a probl;em as long as I reset the axis to its home position at startup, but it would be nice to shut it dow and be able to re-start in exactly the same position. 
In other words, when I start up, I have to jog +0.0005 inches and shut down to reboot so that I am at my prefereed machine zero.  Any idea what would cause this loss of 0.0005 in.  at shut down?  It is extremely consistant.
« Last Edit: October 29, 2006, 07:44:55 PM by Halfnutz »
Re: erratic behavior on servo machine
« Reply #17 on: October 30, 2006, 07:55:18 AM »
The only way that you are ever going to get better then that is with ABS encoders... we don't run them so I think you need to home the machine :) Is homing that machine that big of a problem? We do it many times a day when we are running the mills at the shop :)


Thanks
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: erratic behavior on servo machine
« Reply #18 on: October 30, 2006, 06:23:29 PM »
No,not a problem, just wanted to make sure that this is normal behavior, I geusse the servo's move slightly when powered down
.  I am still putting this machine together so I will implement homing switches and problems solved.  Thanks
« Last Edit: October 30, 2006, 06:27:08 PM by Halfnutz »