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Unknown cause of axis drive fault

Posted: Mon May 03, 2021 9:32 pm
by 610Garage
I am setting up my newly installed oak board to work with my yaskawa sigma II drives. I followed the steps in the Oak installation manual and a tech bulletin for the sigma II drives. When I got to the step to go to the MDI page, I received an axis 3 drive fault. Cycling Estop clears the fault, but it trips again when I try to enter MDI. I believe I also revise the fault for axis 1 and 2 if I attempt to find home. Not that I have gone through to set up limit switches yet. BUt whatever the issue is, it appears to be on all drives.

I am not sure how to interpret the error code, so I have no idea what to look for. I assume that drive fault indicates that the fault line coming from the drive is triggered. However, when I load up sigmaWin+(the drive setup software) to check out the drive, it indicates that everything is fine. No errors listed or present. I am also able to jog all drives from SigmaWin+. I am sure it is a configuration issue, but I have no idea where to look.

I am also using the Yaskawa drive communication cables from Centroid. THanks in advance.

Application:
MIlltronics VM16 vertical mill
Drives:
X,Y: SGDM-08ADA
Z: SGDM-15ADA-V
The tech bulletin I followed for setting up the yaskawa drives:
https://www.centroidcnc.com/dealersuppo ... ds/295.pdf

Re: Unknown cause of axis drive fault

Posted: Tue May 04, 2021 12:45 am
by cncsnw
Did you remember to wire 24VDC to Oak H2 pins 1 and 2?

Re: Unknown cause of axis drive fault

Posted: Tue May 04, 2021 1:40 pm
by 610Garage
Um..... no. LOL I feel dumb. :oops: :lol: The motors now turn, but X and Y will only move ~.4" before I get an axis position error. Not sure what that means. I'm guessing encoder counts are off, but I don't know to what I adjust. Z axis however won't even move. It trips the same error immediately. That I think may be a timing thing between the brake release and the moto enabling. Or, could it be a current limiting setting? But everything moves fine when I jog through sigmaWin.

Thanks for the help.

Re: Unknown cause of axis drive fault

Posted: Tue May 04, 2021 2:29 pm
by cncsnw
Go to the PID Configuration screen and watch the live data (Error and Abs Pos in particular) while you jog various axes in INCR mode.

That will tell you whether there is a mismatch between the encoder counts out and the step commands in.

Jogging incrementally on the x1 increment will also give you a chance to check whether your Z brake control is working properly or not, before there is time to fault the drive or build up to a position error stall.

Re: Unknown cause of axis drive fault

Posted: Tue May 04, 2021 10:17 pm
by 610Garage
I looked at the PID screen. Errors stack as I move X and Y. So there is definitely a mismatch. Unfortunately, I have no idea what setting to look at. Would it be the Electronic gear ratio on the sigma II drive? I noticed, per the tech bulletin for sigma I and sigma II drives, that ratio is 4/1. For sigma 5 it's 1048576/32768 which is widely different. :)

Z position dosn't move, but error does. The brake disconnects, the motor holds position after a slight jump, but that is it. I think it has a separate issue that I'll look into after I get X and Y working properly.

Re: Unknown cause of axis drive fault

Posted: Wed May 05, 2021 1:03 am
by cncsnw
What is the full part number of your servo motors?

Some lower-budget installations used motors with 13-bit encoders. In that case you will not be able to get more than 8192 counts/rev, and will have to set the Centroid parameters accordingly (change 32768 to 8192).

Re: Unknown cause of axis drive fault

Posted: Wed May 05, 2021 8:21 am
by 610Garage
SGMAH-08A1A21 for the x and y axis. They are 16 bit absolute encoders. I set them to incremental during setup. Please excuse my ignorance, but would setting PG divider to 8192 not override that problem? Or are we talking about counts/rev in?

I did try setting encoder counts per rev to 8192 cause that made more sense then 32768, but it failed equally as well. :D

Re: Unknown cause of axis drive fault

Posted: Wed May 05, 2021 11:51 am
by cncsnw
Try changing Pn202 from 4 to 2. I think TB295 was written with SGMGH motors and 17-bit encoders in mind.

Re: Unknown cause of axis drive fault

Posted: Wed May 05, 2021 12:28 pm
by AcornJosh
Your current issue is definitely related to the counts per revolution.

The drive and control need to match. On the drive you are able to set the encoder counts per rev coming back as well as the expected Quadrature counts coming from the OAK. You need to make sure these match since CNC12 expects Quadrature Counts Out = Encoder counts back.

Follow the tech bulletins the best you can to get started. It confusing with so many different options and models on these drives. I have better luck figure it out experimentally on some of these older drives. If you turn the motor shaft by hand and watch the PID menu, you can tell how many counts are coming back.

Setting the turn ratio to one turn per inch also helps you understand if commanding a 1 inch move moves the shaft one turn or some ratio of that. From here, you can double or halve the ratio in the yaskawa parameters to get it to match the OAK. Once you get it matching, the system should run without position errors.

Re: Unknown cause of axis drive fault

Posted: Wed May 05, 2021 2:48 pm
by 610Garage
cncsnw wrote: Wed May 05, 2021 11:51 am Try changing Pn202 from 4 to 2. I think TB295 was written with SGMGH motors and 17-bit encoders in mind.
Ok, that worked for x and y. Took me a minute to figure out why it worked, but it worked. Math is hard. Lol Z still does nothing. I'm wondering if it is waiting for a brake release signal. Not sure if the drive is aware of the brake or not.