acorn and dmm dyn 4 losing steps

[cncman172]

Jerry,
Almost perfect. Remove the resistor you show on the far left of the page and it will be perfect. The two new resistors you have drawn going to 24V is correct. The wiring looks correct, make some chips.

Russ

[fozzyber]

I just removed that image as that was the dmm db25 flying lead, no real reason to have that in there if someone goes this route instead
jerry

[cncman172]

One more comment on the drawing.

The two pins on the differential driver board that show ground, that is actually supposed to go to the Common terminal on the power supply. Some people have Ground and Common tied together but just to be clear.

Russ

Nice job on the drawing.

[fozzyber]

My dmm cables came in today, this is what I have found...
the wire is 3 ft long, the cable is shielded ( sort of...)
the cable has a shield, the drain for the shield is soldered to the db25 side of the cable. great! not really...
when I hooked my cable up and turned on the system, the motor started to hmm and move oddly.
I shut it all down and wondered what was going on , double checked connections all good.
I checked the ground on db25 of the cable and no ground. ?????
Seems the db25 houseing on the DYN4 is not connected to ground SO NO SHIELDING!!!!
i ran a ground wire to the db25 lugs and the motors stopped moving on their own.
this seems like a major flaw in this cable design..... running the drain wire to something that is not grounded....

Im waiting on the diff. line drivers and hoping that will be better.
With these dmm cables it seems Im still getting interference. and losing steps between acorn and dyn4.
yes I have run test and it all points to interference to communication between acorn and dyn4


jerry

[cncman172]

fozzyber,
Sorry to hear you having all these difficulties. I would ground the shield on the Acorn end of the cable. The Acorn has ground terminals. Also double check that the common wire goes from Acorn to the DYN4. This ensures all signals are working off the same reference. The DYN4 should also have its ground terminal grounded, should be one near the power connections.

All this CNC stuff is full of trials and tribulations. It just a huge learning experience. You will get there trust me. Many of us have been in your boots.

Russ

[martyscncgarage]

You have to ask yourself the question. How is it that everyone else using Acorn and DYN4 don't have a problem?

It seems to me you have an electrical noise issue in your cabinet.
(You say you ran my test and got the same results?)

If you want to test the noise theory, pull the Acorn out of your cabinet, use the power supply that came with Acorn,
Use the cable you got from DMM and only connect one DYN4 drive to Acorn and one motor. Do not power up the cabinet/VFD etc.

This is just a test of Acorn, Dyn4 and one motor. No inputs or outputs, leave Estop in NO.

Or you can wait for the boards that Russ suggested....

[fozzyber]

"You have to ask yourself the question. How is it that everyone else using Acorn and DYN4 don't have a problem?"

I agree What the heck....

"It seems to me you have an electrical noise issue in your cabinet. "

I still agree What the heck....

"If you want to test the noise theory, pull the Acorn out of your cabinet, use the power supply that came with Acorn,
Use the cable you got from DMM and only connect one DYN4 drive to Acorn and one motor. Do not power up the cabinet/VFD etc."

First no vfd to cause issues at this time, second a friend is supposed to bring a scope over soon so we can maybe see interference.
I don't have a factual basis for this but I dont think the issue is with acorn but I feel it is a DMM thing. I have a closed loop hybird stepper I am thinking of hooking it up to maybe do some testing to see what happens.

I might not have as much cnc building experience as you or gary campbell, But this is my 4th machine, the last one I built was a large 5'x10' router (mechmate) with a fairly complex control setup. She might not be pretty but she is robust and stable. So this fairly simple acorn setup giving me fits is very frustrating .
The line devices should be here tommorrow we shall see what comes out of that.
I'll post a few images of my current mechmate machine and of my work.



mechmate

mechmate box

HDU CNC Routed and painted with acrylic insert letters

[fozzyber]

And if I haven't said it before I do appreciate all the help that all the people on this forum have given me thus far. I know it's not necessary for y'all to help other people but it is a thing and I do think y'all
Jerry

[cncman172]

fozzyber,
Just out of curiosity the pictures you just posted, is the blue square in the center of the cabinet your old controller, as I did not see Acorn in that cabinet. Should be a nice machine when you get it all working.

Russ

[fozzyber]

The pics I just posted is my older system ( the mechmate) it uses a HICON integra controller,
I am now doing a thermwood retrofit using the acorn and dmms. You can see the thermwood in the background of the first pic.
The mechmate was a ground up build linner rails HSD spindle rack and pinion movment, and weighs about 3000 lbs.
The thermwood retro fit build is all ball screws and weighs about 8000 lbs!!!!!!
I just posted the pics as sort of a resume" to show I'm not a complete ID10T....

Jerry

fozzyber,
Just out of curiosity the pictures you just posted, is the blue square in the center of the cabinet your old controller, as I did not see Acorn in that cabinet. Should be a nice machine when you get it all working.

Russ