Upograding an old Lcnc system.

Hi guys, haven't been around in a while. Hope all is good with everyone.4

I have a customer that has an old system I did about 7 years ago and the machine has been moved. Getting a weird issue. With every turn of the ballscrew it jumps. With the halscope I can see the f-error and then it corrects itself and it jumps abpout 1/16 of an inch.

I am having a hard time trying to figure out what is causing this.IT is only doing it on the X and Y axis. The Z is perfectly fine.
If I disconnect the velocity command from the mesa 7i77 card and put a battery on the wires going to the drive it works smooth. This I am baffled with.

I would like to upgrade Lcnc to latest version that can update if required. IS the version 2.9 iso version the best way to go? Also the configs I dont really want to start over so how would I get the old config to work on 2.9 version. I think the old opne is 2.6 or 2.7.

Thanks for any ideas,

Bob

 

Once per turn issues may be mechanical (loose coupling)
or encoder problems (dirt on the code wheel)

If you look at the plot, it appears that the feedback data (from the encoder)
just stops at some point.

Do the axis lose position? That is, can you jog back and forth through the 'thump"
and end up in the same mechanical position?

Doesnt really loose position. I dont know to what accuracy but If It doesnt seem to do it when I put a battery on the drive velocity input. IT works fine until I get f-error. I jacked up the ferror in the ini so I can see it move through the transition.

Idont know if I mentioned the exact thing is happening on X andY but not Z and they have the same Servo's, encoders and drives. Plus the encoders are sealed in a casing inside the servo motor cap.
 

You would not expect an error/thump running the motors open-loop
as the error seems to be encoder related (and the encoders are not
involved in open loop motion)

It might be wiring related ( intermittent open or short in the encoder
wiring that's ball screw position related

Are you sure you only get the error once per turn?

Another possible cause of the following error would be loss of the analog output
briefly but having this happen once per turn also suggests some kind of wiring
intermittent

Moving a machine really shakes them up. I would reseat every plugin terminal on the mesa boards and check each screw terminal for tightness before doing any additional troubleshooting. I moved a shop once about a mile and 4 out of 5 PC's failed to start until I did this.

Well it was the encoders.

 

Thats really shaken up!