Encoder Differential Error

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jeingham
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Encoder Differential Error

Post by jeingham »

All,

RESOLVED: Triple check your wiring. I did, found the error, fixed and all is good. Or, simply buy the completed wiring harness and encoders from Centroid; doing so would have saved me a ton of time and frustration. I did learn a thing or two in the process however so all was not lost. Also it turns out that there are several things that can cause that error but checking your wiring might be a great place to start.

And thanks again to all who pitched in here, incredible support.

John

tl;dr

I am getting the "Encoder Differential Error" on boot of CNC12-D Mill v4.14 control.

Encoders all (X,Y&Z) worked when bench tested; all are all Centroid supplied encoders.

>>> Unplugging all the encoders from the machine I get the same "Encoder Differential Error", X,Y&Z <<<

Thinking of disabling the error function via 332-335 but thought I might ask if there might be an explanation as to why the difference between bench test and machine installed board. I did try the bench test again at the machine and was not successful.

tl;dr

This is my first install of Centroid controller. I do have support time but thought I would run it by the forum first. I did plenty of reading and researching herein (this forum) and am not finding anything that makes sense in this case except for the possibility of line noise on the the circuit using here in the shop vs my test area. It is very possible that I missed something setup wise but I've been through the manual very many times and nothing is jumping out at me. That said the obvious may be obscure to this nube.

Thanks in advance!

John
Attachments
report_0102202332_2020-07-10_19-34-51.txt
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report_0102202332_2020-07-10_19-34-51.zip
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Last edited by jeingham on Fri Jul 17, 2020 7:25 pm, edited 2 times in total.
cncsnw
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Re: Encoder Differential Error

Post by cncsnw »

Can you post some pictures showing how you have the encoders connected through to the Allin1DC?

This is most likely a connection issue.

Do the "Abs Pos" values on the PID Configuration screen (F1/Setup -> F3/Config -> "137" -> F4/PID) change at all when you turn the encoders?
aamir
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Re: Encoder Differential Error

Post by aamir »

John
For differential error check following
1)your Motors took unusual high current or unusual load on any axis ?
2)only one axis give error or all axis ?
3) Normally Z-axis on load and need to check writing route and shielding
4)if you use vfd and not properly ground spindle motor with VFD with proper guage wire then their is possibility of differential error.
CJD
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Re: Encoder Differential Error

Post by CJD »

I had that issue that would come and go for several months. Mine was always on the 4th axis encoder. When I watched the step count, the other servos were rock solid, but that one would drift back and forth several steps, even when the servo was stationary. I assumed I had a bad encoder, and was shopping for one under the $500 going rate.

On a whim, I removed the servo cap and cleaned all the internals in the encoder area with contact cleaner, and I cycled the connectors a couple times each. I have not had the issue since. These are optical encoders, and I think some dust and dirt can cause them to act up.

Oh...I was wrong. I did have one more instance where I started to get the machine to trip with "encoder error". It turns out I had used a brass mallet to tap the 4th axis trying to tram it in. In tapping I had knocked a connector off inside the encoder cap. Dumb mistake.

Anyway, the moral of all this, is the easiest thing to check are all your connections and to clean the encoder.
martyscncgarage
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Re: Encoder Differential Error

Post by martyscncgarage »

I took a look at your message log. It is attached for reference. (You can see this log by going to F7 Utility, F9 Logs, F1 Errors)
It seems your encoder errors have been there from the beginning.
How did you wire them up to All in One DC? Did you buy the Centroid Encoder cables (SMART MOVE if you did)
Have you been following the All in One Installation guide step by step? Did you ensure the encoder counts were counting correctly when the servo motor shaft was turned counter clockwise?

Pictures as Marc requested are worth a thousand words (along with the information requested above)

Marty
Attachments
msg_log.txt
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Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
martyscncgarage
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Re: Encoder Differential Error

Post by martyscncgarage »

Also, the way you configured your home/limit switches aren't going to work as they are for X/Y. Please tell us where your switches are on your machine and why you configured the software the way you did:
Limits.JPG
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
jeingham
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Re: Encoder Differential Error

Post by jeingham »

cncnw,

Thanks for looking at this, answers to your questions below:
cncsnw wrote: Fri Jul 10, 2020 9:24 pm 1. >> Can you post some pictures showing how you have the encoders connected through to the Allin1DC?
2. >> This is most likely a connection issue.
3. >> Do the "Abs Pos" values on the PID Configuration screen (F1/Setup -> F3/Config -> "137" -> F4/PID) change at all when you turn the encoders?
1. >> Here are some pictures of the control box. Not quite sure what you need to assess exactly, glad to provide more specifics if needed.
20200713_161259.jpg
20200713_161157.jpg
20200713_161139.jpg
20200713_160028.jpg
20200713_155402.jpg
20200713_155338.jpg
20200713_154319.jpg
20200713_154309.jpg
20200713_154304.jpg
20200713_154304.jpg
20200713_154247.jpg
2. >> Right, I hope it is that simple. Not the greatest wiring job but still a mystery as to why the same error when the encoders are not connected at all.

3. >> I saw no changes to any of the parameters in the PID menu while rotating the X Y or Z.

Please let me know if you need anything else. I made a short video of my machine highlighting the the wire layout and a few other things that might be of significance. Will post that with a few more photos in a few minutes.

John
jeingham
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Re: Encoder Differential Error

Post by jeingham »

Marty,

Thanks for looking at this for me, answers to your questions and photos are below:
martyscncgarage wrote: Mon Jul 13, 2020 10:30 am I took a look at your message log. It is attached for reference. (You can see this log by going to F7 Utility, F9 Logs, F1 Errors)
1. >> It seems your encoder errors have been there from the beginning.
2. >> How did you wire them up to All in One DC? Did you buy the Centroid Encoder cables (SMART MOVE if you did)
3. >> Have you been following the All in One Installation guide step by step?
4. >> Did you ensure the encoder counts were counting correctly when the servo motor shaft was turned counter clockwise?

5. >> Pictures as Marc requested are worth a thousand words (along with the information requested above)

Marty

1. >> I switched PCs after the bench test was done at my testing bench and did it all again it the machine after installing the base panel which I had removed for initial wiring and bench test. So, 'from the beginning' is only at the machine with the new PC. As I say here I did go through the entire bench test again at the machine but could not get the encoders to effect the readout at that time. That was when I discovered the problem. The original bench test did result in counts close to 8000 on one full rotation and on all three axes.

2. >> I did not buy the fully assembled cable set, just the end part kits and cable to do the cable assembly myself. At this point I do regret that but (at the time) I thought I needed to thread the wiring through the flexible cable and thought I would have had to remove the large couplings to do so anyway so why not buy just the parts. Looking back on it now I could have gone the other direction and simple re-soldered the DB9s on the other end using the other fully assembled cables as reference. A very plebe mistake that was. Also I had initially chosen to use mechanical DB9s (did not know I had any soldering chops then, do now, all DB9s are of the soldered type at this point) but switched to soldered connections in the end anyway so that was my bad. If buying Centroid fully assembled cables is what it takes to get it done I am willing to do so. I would like to know what the problem is though and try to fix it if possible of course.

3. >> I have done my best to follow the manual step by step; I do not think I missed anything but obviously there is something wrong. Likely it is my bad as everything else has gone pretty smoothly including my first run through of the encoder test with the first PC. I chose to use a smaller form PC so I could fit it into the control box.

4. >> Yes, as I mention above using the first PC all tested out well, I was able to generate the 8K signals in one rev on all axes.

5> >> Photos are attached in my response to cncnw (Marc?) Have video tour as well that I will post momentarily.
martyscncgarage
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Location: Mesa, AZ

Re: Encoder Differential Error

Post by martyscncgarage »

I noticed you PID screen, your index pulses are all showing (asterisk next to each axis letter) that's too coincidental. Are your encoders connected when you took that picture?

So you put the connectors on both ends of the cable. Where did you get the cable?
Show picture of the encoder connector and it's pin assignments and you cable color chart you made and followed along with your DB9 pin connection
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
jeingham
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Re: Encoder Differential Error

Post by jeingham »

Aamir,

Thanks for looking at this, answers to your questions are below:
aamir wrote: Fri Jul 10, 2020 9:43 pm John
For differential error check following
1)your Motors took unusual high current or unusual load on any axis ?
2)only one axis give error or all axis ?
3) Normally Z-axis on load and need to check writing route and shielding
4)if you use vfd and not properly ground spindle motor with VFD with proper guage wire then their is possibility of differential error.
1. >> No, the motors have not been run. I did follow testing Centroid motor continuity testing procedures and watched Marty's video on the topic following both to the best of my ability. All motors are in good shape by that testing. The machine is new to me so I have no idea as to how they were stressed in the past.

2. >> All axes

3. >> I am using Centroid supplied shielded cable and connectors. I did all the wiring myself and believe i got it all right but at this point I am not sure.

4. >> The VFD is not powered up yet. I am using a separate 110 VAC circuit to power the board and motors.

John
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