Author Topic: Motors won't sit still  (Read 1068 times)

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Offline marc1b

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Motors won't sit still
« on: January 31, 2018, 11:51:47 AM »
I have been running my Mach3/Intergra (closed loop option) machine for a few years no problem with Maxsine drives & servos. A drive recently failed and I changed drives to the next larger model (TL10F to TL15F) which required setting parameters and  re-tuning the drives. So I got that all done and everything mostly works.

However when Mach is running the DRO's for X & Y are bouncing around by .0001 or so. There is a monitor utility in the Maxsine software that confirms the motors are actually moving. If I kill Mach the movement stops. I'm trying to figure out what I missed.

Thanks for any input!

Offline Vital System Support

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Re: Motors won't sit still
« Reply #1 on: January 31, 2018, 03:39:15 PM »
The motor encoders will bounce if the motors are not installed into a machine. Once the motors are installed into a machine and there is load on the motors, the encoders should sit still.

Offline marc1b

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Re: Motors won't sit still
« Reply #2 on: January 31, 2018, 03:51:19 PM »
Yes I can understand that but this is a live machine. Did not have this problem with the previous drives. And does not do it unless Mach is running. See videos here

https://drive.google.com/open?id=1uIjDfTO16HN-9hBmevzmx6gnxvB7Rluw

Offline TOTALLYRC

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Re: Motors won't sit still
« Reply #3 on: January 31, 2018, 08:28:30 PM »
A servo system will bounce back and forth (This is called Dithering) trying to maintain position since when it is not seeing encoder counts it doesn't know what to do(simplification of the actual reason). Try putting a number greater than 0 in the dead band setting. On my machine which has 80K steps/inch it takes at least 10 to quiet it down. Since 10K steps/inch is .0001" and I have 8 times more stpes than that 10 is really nothing.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

Offline marc1b

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Re: Motors won't sit still
« Reply #4 on: February 04, 2018, 11:54:34 AM »
Got it figured out. I had to set the drives to the correct model motors and be a little less aggressive with my tuning in the drive.