X servo error - delta 20 control

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11-14-2022, 02:20 AM
leeko

X servo error - delta 20 control

While trying to resurrect my Clausing Kondia fv-1 with delta 20 control, I've been getting fairly frequent x servo errors which result in faulting out of the running program. The error message is:

Emergency stop
X servo error
Loss of feedback or no motion detected on x axis
Enter reset to continue
Pic revision #006 - 6/06/88
Spindle SW is in auto position

From reading a few threads, I gather the problem is either related to
1) higher than expected friction/resistance to movement,
2) a defective x servo encoder, or
3) a problem with connections or cable from the encoder

Before i start dismantling stuff, is there a good way to figure where to start troubleshooting this?

Thanks,

Lee
11-14-2022, 02:37 AM
machinehop5

Re: X servo error - delta 20 control

....which servo amp's do you have?

...check the Lag Display when Jogging each Axis and see if the numbers are about the same. XY should be equal.
11-14-2022, 04:15 AM
leeko

Quote:

Originally Posted by machinehop5

....which servo amp's do you have?

...check the Lag Display when Jogging each Axis and see if the numbers are about the same. XY should be equal.

Hi,

I have baldor motors and servo dynamics drives. I checked the axis lag, and it seems really high? For all 3 axes though. I don't know enough about servos to know what that means...

X - 000.0368
Y - 000.0967
Z - 000.0906

These numbers were obtained with the respective axis moving. When stopped, they were X 0.0000, Y.0.0000, Z 0.0001

Thanks again,

Lee
11-14-2022, 04:39 AM
machinehop5

1 Attachment(s)

Re: X servo error - delta 20 control

...there is a Model # on the Amps somewhere SDxxxx...or a photo would help. Most likely you have SD1525's and there are some Pots on the X Axis board that are adjustable.
The Pot that is marked SIG is the one we want to try adjusting.
If, x axis is faulting I would say YZ axis are ok....adjust the X SIG pot one turn CW and see if, the Lag numbers change on X axis. These Pots are 20 turns so, you cant hurt much....lol.

Attachment 486136
11-14-2022, 05:24 AM
leeko

Re: X servo error - delta 20 control

Thanks for the tip. I'll take a look at the model number this evening

Should this adjustment be done with the control on or off?

Thanks
11-14-2022, 05:37 AM
leeko

Quote:

Originally Posted by machinehop5

...there is a Model # on the Amps somewhere SDxxxx...or a photo would help. Most likely you have SD1525's and there are some Pots on the X Axis board that are adjustable.
The Pot that is marked SIG is the one we want to try adjusting.
If, x axis is faulting I would say YZ axis are ok....adjust the X SIG pot one turn CW and see if, the Lag numbers change on X axis. These Pots are 20 turns so, you cant hurt much....lol.

Attachment 486136

Yes, they're SD1525's.
With the machine off, I turned the sig pot for the x axis one full turn clockwise. the new x axis lag reads 000.0310.

I guess that means I need to turn a few turns in the counterclockwise direction?

Lee
11-14-2022, 05:47 AM
machinehop5

Re: X servo error - delta 20 control

..bingo. Yes, try CCW and try to match the Y axis lag. It sounds like someone has been playing with the adjustments. So, adjust it a few turns or as close to Y axis lag and test running Programs to see if the error is gone.
11-14-2022, 05:53 AM
machinehop5

Re: X servo error - delta 20 control

Quote:

Originally Posted by leeko

Thanks for the tip. I'll take a look at the model number this evening

Should this adjustment be done with the control on or off?

Thanks

...ON ok with Plastic Screw drive, but OFFmaybe better
11-14-2022, 05:59 AM
leeko

Quote:

Originally Posted by leeko

Yes, they're SD1525's.
With the machine off, I turned the sig pot for the x axis one full turn clockwise. the new x axis lag reads 000.0310.

I guess that means I need to turn a few turns in the counterclockwise direction?

Lee

I tried turning in the counterclockwise direction. I got about 3 turns, and the x axis value increased to 0.0660, but the axis lag at rest started to creep up (0.0002-0.0003). I tried to go further, but the resting lag value got crazy high. At 0.0660, I tried to run a program but it almost immediately gave me an x axis servo error

Lee
11-14-2022, 06:14 AM
machinehop5

Re: X servo error - delta 20 control

...ok, so when machine NOT moving the Lag Display should be 0 is the goal...but, it does bounce some. The adjustment for that is the BAL Pot. So, you may have to adjust it, after changing the SIG pot.

If, the X axis is mechanically ok, and is free and easy to turn the ball screw by hand ...further adjustment with Volt Meter would be the next step.

I do have a manual for the SD1525pdf but, its 16mb

DJ
11-14-2022, 06:27 AM
leeko

Quote:

Originally Posted by machinehop5

...ok, so when machine NOT moving the Lag Display should be 0 is the goal...but, it does bounce some. The adjustment for that is the BAL Pot. So, you may have to adjust it, after changing the SIG pot.

If, the X axis is mechanically ok, and is free and easy to turn the ball screw by hand ...further adjustment with Volt Meter would be the next step.

I do have a manual for the SD1525pdf but, its 16mb

DJ

Thanks again for all this handholding :)

I hadn't thought to check if the ballscrew turns freely by hand - will take a look at that when I'm back out there tomorrow

When I was turning counterclockwise, if I went back more than those 3 turns or so the resting axis lag went up to about 0.020. I tried to see what the lag was like while moving at that setting, but it immediately faulted out when I jogged x. So, I backed off a bit.

Would it be reasonable to adjust sig until resting lag starts to rise, then adjust BAL back to zero, then repeat until I can get the X lag while moving to match the Y?

I'd love to see the manual for the sd1525s, thanks! I'll pm my email address.

Thanks again,

Lee
11-14-2022, 04:42 PM
machinehop5

Re: X servo error - delta 20 control

Quote:

Originally Posted by leeko

Thanks again for all this handholding :)

I'd love to see the manual for the sd1525s, thanks! I'll pm my email address.

Thanks again,

Lee

Your welcome.

Send me an email address and I will email a copy of the SD1525 manual and we can go from there why X axis is faulting out.

DJ
11-17-2022, 01:43 AM
leeko

Re: X servo error - delta 20 control

Thanks for sending over the manual! Work got a little nuts the last couple of days, so it might be the weekend before I can work some more on adjusting the axis lag but will keep you posted :)

Meantime, I checked the x ballscrew. If I grab it with a couple of fingers and my thumb, I can turn it without too much difficulty. I wouldn't describe it as free and easy - there is some friction and it definitely doesn't keep spinning when I let go. How much force should I expect? (How long is a piece of string...)

Thanks again,

Lee
11-17-2022, 07:17 PM
machinehop5

Re: X servo error - delta 20 control

Hi Lee,

That all sounds good on the X axis ball screw, etc. So, must be the SD1525-10 (double check that dash #) servo card and I would suggest finding/buying a spare or two. Because the Card you have may have more problems then just adjustments. Ebay,..I see has a few of them but, anything over 75-125 dollars for one card I would pass and wait for better deal.

DJ
11-20-2022, 02:21 AM
leeko

Quote:

Originally Posted by machinehop5

Hi Lee,

That all sounds good on the X axis ball screw, etc. So, must be the SD1525-10 (double check that dash #) servo card and I would suggest finding/buying a spare or two. Because the Card you have may have more problems then just adjustments. Ebay,..I see has a few of them but, anything over 75-125 dollars for one card I would pass and wait for better deal.

DJ

Hi,

I was able to get back out in the shop, and spent some time adjusting the pots on the x axis card. I was able to get the axis lags to match fairly well:

X = 0.182 to 0.185 (depending on direction)
Y = 0.182 to 0.183
Z = 0.163 to 0.165

The axis lag at rest, after adjusting the bal pot, was

X = 0.0000 to 0.0001
Y = 0.0000 to 0.0000
Z = 0.0000 to 0.0001

Unfortunately, my x axis servo errors are persisting. I also had a single x axis runaway error after resuming (reset) from a servo error. I believe I also had a single Y axis servo error too, but I cleared it before I realized, and am not sure it was actually Y.

Ill start looking for a new servo drive card or two as you suggested. You had previously mentioned checking resistances on the card to help with pot adjustment - is there something in the info I provided that tells you it won't help to troubleshoot this card any further?

Thanks again

Lee
11-20-2022, 06:28 PM
leeko

Ok, I think I made some progress

Having (maybe) seen an error on the Y axis as well, I got to wondering if maybe it's not a problem with the drive itself. I switched the phases on the power in from the RPC, and immediately the servo errors got more frequent. I was also getting them on all three axes. I tried all combinations of the three phases, but the original one I had was the best. I think this tells me that it could be related to the unbalanced 3ph input.

Next, I tried to figure out when the errors were happening. They seem much more frequent with the spindle running. With the spindle off, I can jog both x and y simultaneously in rapid and rarely (but not never) get an error. With the spindle on, more frequent.

Next, I tried switching the spindle on manually, while jogging in X. Even if it doesn't error, there is a visible stutter in the X axis movement while the spindle is spooling up. I believe this is where my issues may be coming from.

I've seen another thread where they were talking about switching the incoming power to 220v single phase, and running the spindle from a VFD. I think this might be my best route, as it would do away with the RPC completely.

If anyone has any suggestions or input as to that approach, I'd love to hear it. On the other hand, if I'm barking up the wrong tree with this, let me know!

Thanks very much,

Lee
11-22-2022, 06:02 AM
leeko

Well, I successfully switched the mill over to single phase input (minus the spindle motor - VFD will be delivered in a few days). I can now switch the control and the servos on without listening to the RPC :)

Unfortunately, I'm still getting x servo errors. Ah well - back to troubleshooting. The servo covers will be coming off tomorrow to look at the encoders...

Also, without the noise from the RPC I can now hear a high pitched whine from the Dynapath cabinet... Wonder if the fans are on their way out...

Lee
11-23-2022, 05:39 AM
machinehop5

Re: X servo error - delta 20 control

Hi Lee,

...that high pitch whine is normal for DC Servos. If, the Motors/Amps for X and Y the are same size, One thing you can try is to swap the Y axis Amp card with X. Power OFF machine for 10-15 mins to let discharge the Big Blue Cap 1st (use a Meter on DC 200VDC or more scale on the Cap to check its drained)....then the wiring is all Plugs and can easily be swap, There are two hold down screws down inside that hold the card only need to be loosen a turn or two with long screw driver to remove the card. Then, do some Lag testing to see if, the problem moves to Y and X runs ok. Then we'll know its card adjustment or a bad card.

Note: When doing the Lag testing the Feedrate must be the same, Write a small program to Loop/repeat a back and forth one Axis at a time move of about 4-5" at some steady rate like 40 IPM.