Centroid Community CNC Support Forum

I bought my acorn board and cnc12 software upgrade about 1 Jan 2021. I have made several tests with stepper motors one was with a nema 23 closed loop motor. The test results were successful on both closed loop and open loop motors. But subsequently the motors would not respond to a direction change. I have tried it with at least two other open loop motors with different drivers and get similar results, motor would not respond to a change in direction. I put a scope on the -step output on the acorn and I get a 50ms pulse width. which seem too long. I suspect something has happened to the board, but am not sure. I was thinking of buying a new board and trying that. or could I return the board for evaluation. what do you suggest? I would appreciate any suggestions.

Richard Thomas

It is more likely to be a problem with the direction signal from the Acorn to your drivers.

Did you check that?

PLEASE take the time to follow this post and provide better information. Remember, we cannot "SEE" what you "SEE"
viewtopic.php?f=60&t=1043
The better information provide the better suggestions we can make.
Marty

50ms is 20 steps per second. Is it possible that you've selected the wrong time base on your scope? Take the reciprocol of the steps per second to get the time per step, i.e., 1/100,000 = 0.000010, 1/200,000=0.000005, and 1/400,000=0.0000025. If you are only sending 20 steps per second to the motors, then 50ms would show up on your scope.

Which stepper motor drive are you using? How is it connected to the Acorn? Are you using +5VDC for common or are you using GND? Some drivers, such as the Gecko G201 and Gecko G202, require +5VDC for common. Other drivers, such as the Gecko G203v, require GND for common. Some drivers, such as the DM542 that I use, don't care, as long as you select the proper polarity of step and direction signal.

We are all guessing until the original poster follows the forum requirements for asking for help.
viewtopic.php?f=60&t=3539

post a fresh report.zip.

I have tried it with at least two other open loop motors with different drivers and get similar results, motor would not respond to a change in direction

I've seen this issue before and it was cured by changing a switch setting on the stepper motor drive. Some have this setting and some don't. There may be a switch for "bi-directional use". If the switch comes set to the wrong position, the motor will always move in the same direction regardless of the direction command.

Knowing how easy it is to install a stepper motor with Acorn I would expect it to work right out of the box if the switches are set properly.

My 2 cents worth,

Dave C.