acorn and dmm dyn 4 losing steps

[fozzyber]

I seem to losing steps with my setup, I run a simple program the runs the drive to x=100 and back to x=0 about 4 times and it does not go back to zero. I put a peice of tape on the motor vertically, and it does not return to vertical (TO ZERO) I double checked the position in dmm monitor software and the encoder is showing about 6500 off from the starting position. more the longer the test. I have set my freq. form 400,000 to 200,000 and 100,000 to even 40,000 with nothing making a change. has anyone seen anything like this?
I am new to acron, but not cnc building, I have built 3 but they all used mach3,
the problem seems to be betwqeen acorn and the dyn4s as all the drives(3) seem to exhibit the same issue of losing steps.

thanks
jerry

report_985DADEC3FE0-0423180848_2019-01-20_19-18-01.zip

(178.25 KiB) Downloaded 118 times

[cnckeith]

jerry,
hello. post photos of your cabling please.
are you using the DMM cable or did you make it yourself? etc..
and wanted to be sure you saw this setup guide attached and the dyn4 "build your own cable" schematic

[fozzyber]

I did make my own db25 cable
I'll look at the links you posted

[fozzyber]

changed all my settings as per documentation with no change. I'm still no coming back to zero.
I'll double check my wiring.
jerry

[cnckeith]

dyn4 runs off the Acorn screw terminals, not the db25 on acorn just to be clear.

[fozzyber]

Yes i have attached the wiring from the dyn 4 drive to the acorn via the screw terminals not the db25 on the acorn.
Not to be sarcastic but you can see that in the link of the first picture that I attached
Thank you for your help thus far.
Jerey

[cnckeith]

yes indeed thanks for the reminder.

are the cables twisted pair with shield and drain? my eyes can't make that out from the photos.

[fozzyber]

i have double checked the pin out and they are correct.
the wires are not twisted pair and are not shielded and drained.
jerry

[cnckeith]

yeah to get reliable signals above 100 khz you'll need twisted pair shielded cable with drain connected to ground at one end.

DMM sells a DYN4 to Acorn cable, that is an option as well.

[martyscncgarage]

Did you set up the DYN4 correctly with DMMDRV software? Set gear and Line to 2000. Set Acorn to 8000 steps per rev.

Please show a video of the machine and what you are doing to test the issue.

You tell Dyn4 to turn the motor one rev, it will turn that motor one rev. Dyn4 is making sure of that with the encoder. If it doesn't, it faults. The only two issues I can see here is there is mechanical issues with your machine or your cabling is suspect from Acorn to DYN4.

I ALWAYS recommend buying the DB25 cables from DMM to connect to Acorn. Your aggravation and the risk in miswiring isn't worth it.

I've setup many Acorn/Dyn4 combinations with no issue.
Give us more information about how you are testing the travel, a video showing how you are doing it would be very helpful. Post it to YouTube and then provide a link.

Remember, you can "SEE" your setup, wiring, procedure, we can't. All we have to go by is your description. A little more info and we should be able to help.
Marty