Another DYN4 and Acorn Losing Steps Issue

[cnckeith]

maybe DMM can comment.
what firmware version on the DYN4's do you have?

[martyscncgarage]

As the photo shows, this was done on all four axis drives.

It seems disengenuous to have the published schematics and setup guides barked at us when there is clearly an issue with DYN4 connected to the Acorn screw terminals dropping steps. I wasted a lot of time troubleshooting a supposed known working combination.

My machine is now working as expected.

https://youtu.be/mADw8_DT-p8

I'm glad you got your machine working to your satisfaction.

I have follwed the DMM Schematics, used their cable and have also hand wired the DB25 connector per the Centroid schematics without issue.

You did not comment on the video I posted porting the DYN4 encoder signals into Acorn's Encoder port showing the two matched.

The video I posted, used the DB25 flying lead cable should lend some credence to the fact that the combination does work. I would not be so quick to say it is an issue with the vendors and their schematics. It would take someone much more knowledgeable than I to sit at a bench with an oscilloscope to look at things at that level more closely.

Marty

[slodat]

Yes, I did see your video. I’m not sure what that has to do with what I’m showing as a repeatable problem that I, and others, have with the configuration that I’m told works out of the box. Did you read this thread and review my test results??

I bought the DMM cables because you (literally) said they are the easy, direct path to a working Acorn/DYN4 system. When I had issues I was told to RTFM (read the __ manual). I did and it doesn’t work.

My aim was to share what I found, in an effort to contribute to the Acorn community and ecosystem in hopes it would help others that may see the same thing and possibly help the vendors with an issue that some of us are having.

I did a lot of testing. It is all in this thread. When step/direction are connected to the screw terminals with +24v on the brown wire with the internal 2k resistor, I lose counts. Using the same encoder you use.

What is going on in the circuit, in my opinion, should be worth looking into. It’s ok with me if it’s not. I suspect the issue is in the quantity of pulses I’m asking to work with the steps/rev and feedrates. If I had noise, wouldn’t it be there on the 5v step/direction outputs? My thinking is it would. To be fair, I’m not sure how to make that determination.

Again, my aim is to share what I’m observing, in an effort to help others, the manufactures and this community of people that are REALLY happy Centroid has made Acorn available to us at its price point.

If it would be beneficial, I can order the parts to make a cable to perform the same test you did. I’m in the middle of no where, so I have to order it in. In my mind reading the encoder absolute position was the same thing.

I appreciate everyone’s time and efforts in helping me get this sorted out.

Steven

[cnckeith]

fyi....all servo systems have a following error and or overshoot error when positioning... is this what you are looking at?
these values that are typically reported by the Servo drive manufactures tuning software....and when the drive and motor are tuned properly ....are completely irrelevant to a machine tool (especially a router:-) as they can be an order of magnitude (or more) smaller than what the machine tool's physical tolerances are capable of. The encoder test is great..alternative would be to put a glass scale on the machine and connect that to the Acorn encoder port or a DRO readout..a good scale won't lie if it is lined up with the axis properly. (several users have done this in the past for various reasons like ballscrew compensation.)

[Dale Powell]

Hello, my system is showing the same problem, can someone simplifly the this for me, dmm settings, acorn settings, and wiring. I was pulling my hair out thinking that I wasn't following everything correctly, Dmm show settings and MARTY settings are different, only looking for the best way to get it done correctly.
Thank you.
Dale Powell.

[martyscncgarage]

Hello, my system is showing the same problem, can someone simplifly the this for me, dmm settings, acorn settings, and wiring. I was pulling my hair out thinking that I wasn't following everything correctly, Dmm show settings and MARTY settings are different, only looking for the best way to get it done correctly.
Thank you.
Dale Powell.

See my post about his issue. You can contact DMM and request new cables if you wish. Follow the Centroid schematic and make your own, or wire to the DB25.

[Dale Powell]

One more thing, when a drive faults out shouldn't it alert Acorn to stop all motions and the program

[martyscncgarage]

One more thing, when a drive faults out shouldn't it alert Acorn to stop all motions and the program

Yes.
Put 991 in the search box and read up.

[qjones]

Just when I thought I had gotten out of the Screw Terminals vs DB25 woods. I think I am having this issue to the more I think about a few random cuts that dropped a hair low. I blamed it on a possible tool offset being wrong. But in hindsight I don't think it was. I am not looking forward to having to pull my mill back out from the wall to get back to my electronics after I just leveled and calibrated it all finally.

2 questions:
1) If you remove/replace the resistor in the DMM Centroid cable SHOULD it still work on the screw terminal outputs?
2) Since the original schematics originally didn't indicate I would have to use the DB25 head my acorn board is mounted in a tight spot that I don't have much room to come off with a DB25 breakout. Does anyone know of a good right angled connector or breakout or cable to use in a tight space?

[slodat]

Just my two cents.. I would connect step and direction to the DB25 and the brown wire to +5v.