Encoder Error

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Greg82
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Encoder Error

Post by Greg82 »

I am working on a new install on a Biesse Router. The router has Yaskawa SGDH drives. I got the oak, nuc and yaskawa pre made cables to make a quick install. The X axis (Axis 1) was up and running without a problem. The Y (Axis 2) and Z (Axis 3) are both giving me encoder error count that doesn't go away when the machine stops.

The DRO on Y and Z would not go to where they were commanded. There would always be a distance to go left when movement stopped.

I originally assumed this was bad encoders on Y and Z so I swapped the X and Y encoders since they were the same and the problem stayed on the Y axis. I then connected the Y motor and encoder to the X axis servo drive and there was no error. This ruled out the encoder, motor and wires were working properly on the Y axis so I put the motor and encoder cables back to the proper drives.

I double triple and quadruple checked that the settings in the drives were right and even tried changing the PG Divider setting in the drives which changed the error count but didn't solve the problem.

I then connected my Y axis servo drive to (Axis 1) port on the oak and there was no error. The axis moved with little error count and zeroed out when the motor stopped. I monitored this with the Alt-P screen and also the DRO. Connecting Z drive to (Axis 1) port also worked properly.

I tried changing the revs/in and the jog speeds on the Y and Z but still get an error when plugged into ports (Axis 2), (Axis 3) and (Axis 4). I can Jog the Y axis a high speeds while plugged into (Axis 1) port without error.

So where I am is all drives seem to work as they should when plugged into (Axis 1) port on the Oak but not when they are plugged into any of the other ports.
Are there parameters I may have missed that control how each axis port handles the drives? I have setting 256 set to precision mode. Is there one for each port?

There is a picture of the drives and a picture of the Alt-P screen showing the motor stopped before it gets to its commanded location with the encoder count error. This error increases when traveling one direction and decreases when traveling back but does not zero when ABS also gets to zero. The report will show only one axis enabled but 1-4 were enabled and disabled as I tried different ports and settings. I also tried naming (Axis 1) port to Y to see if that would show any Y specific settings that were creating an error but it still worked properly.
Attachments
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cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: Encoder Error

Post by cncsnw »

All things considered, this looks like a hardware issue. I recommend contacting Centroid Support.

If you want to make the Y axis use port 1, and the X axis use port 2, while retaining all the software settings for the respective axes, you can do that by setting P300 = 2 and P301 = 1; and setting P308 = 2 and P309 = 1.
cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: Encoder Error

Post by cncsnw »

Is the distance that the axis actually moves accurately reflected on the DRO (even though it is less than what the axis should have moved)?

If the move distance comes up short, but the DRO is accurate, then the problem is with outgoing command pulses to the drives. If the DRO is also not accurate, then there is also a problem with encoder pulses coming back from the drives.
Greg82
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Re: Encoder Error

Post by Greg82 »

I just made videos of the exact same servo drive, motor and encoder plugged into each axis port on the Oak.
I set all the axis settings to default before running the test (Max speed, Accel). I set the the rev/in to 1 to be able to easily calculated the error per rotation.

I only enabled one axis at a time and it was always named X for port 1 to 4. I had a dial set on 0 and ran a program "G0 X4, G4 P2, G0 X0, G4 P2" 4 times and the drive plugged into (Axis 1) worked perfect.

(Axis 1) ended with .000 error from returning to 0 on dial with a DRO read out of .0000 (-1 error on PID screen)
(Axis 2) ended with .004 error from returning to 0 on dial with a DRO read out of -.0053 (-175 error on PID screen)
(Axis 3) ended with .001 error from returning to 0 on dial with a DRO read out of -.0015 (-49 error on PID screen)
(Axis 4) ended with .01 error from returning to 0 on dial with a DRO read out of -.0106 (-348 error on PID screen)

The error count increases each cycle to 4" and back to 0

I will work on getting the videos uploaded.
Greg82
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Joined: Tue Nov 15, 2022 8:30 pm
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Re: Encoder Error

Post by Greg82 »




Greg82
Posts: 6
Joined: Tue Nov 15, 2022 8:30 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: Yes
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No

Re: Encoder Error

Post by Greg82 »

Also after running the program and the DRO doesn't return to 0, I can jog it back to .0000 and the dial then reads 0 so it seems like the problem is in what is being commanded, not encoder error.
m5white
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Re: Encoder Error

Post by m5white »

Hi Greg82.

Did you resolve this problem? My system is doing the exact same thing. I am using OAK with DMM 1.3 kw motors and DYN4 drives. Anything one of the 4 axis motor/cable and drive systems I plug into Axis 1 works fine. I get a repeatable and linear PID error count with any other Axis connection.
rjtechserv
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Re: Encoder Error

Post by rjtechserv »

Exactly what the lathe I'm working on is doing. I finally sent my board into Centroid for a closer look. Axis 1 works fine. Axis 2-4 error out. If we discover anything helpful I'll post it for you! Yaskawa Sigma 2 to Oak
Rob Jackson

RJ Technical Services
m5white
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CNC Control System Serial Number: Oak A900946, Oak A901222
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Re: Encoder Error

Post by m5white »

I would greatly appreciate that. I did a lot more testing; swapping out cables, drives, motors, running test programs, swapping out power wires from X and Y, swapping leg one and two, two with three etc., wired OAK directly to shop 110 VAC rather than go through transformer, Isolated 24VAC for e-stop... What I did find is that axis 2-4 work well if I do not go any faster than 1 IMP feed rate. Axis one has no issues going as fast as 200 IMP which is my target max travel speed.
eng199
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Location: Howard, PA

Re: Encoder Error

Post by eng199 »

rjtechserv wrote: Thu Mar 16, 2023 4:25 pm I finally sent my board into Centroid for a closer look. Axis 1 works fine. Axis 2-4 error out. If we discover anything helpful I'll post it for you!
We have not been able to reproduce the problem yet, but will keep trying. 2 axes ran over the weekend with your Oak and cnct directory. I sent email to you and m5white.
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