I ran into a snag after getting all the drives/motors bench tested successfully. I have the following outputs coming from the proprietary BOB of the machine (here is what the corresponding inputs look like from the previous stepper drivers):
Attachment 419186
I'm using the cable that would normally plug into these drives, breaking out the stp/dir signal and running them into the DMM breakout board to go to the drivers.
The stp/dir signals are:
Pin1. CW-
Pin 2. CW+
Pin3. DR/CC-
Pin4. DR/CC+
(I'm not bothering with the FREE (enable signal) yet, if at all.
Voltage between CW- and CW+ is pulses (I can't get an accurate read on voltage without a scope but pretty sure they are 4.7v)
Voltage between DR/CC- and DR/CC+ is a constant 4.7v one direction and 0v the other.
Everything seems normal there.
OK so I run those signals into the DMM breakout board DB25 port here:
Attachment 419188
For Z axis:
CW- -----> pin 22 (gnd)
CW+ -------> pin 7 (z step)
Everything works great, smooth motion on the motor but in only one direction, clockwise.
Then I finish that axis by hooking up the direction input:
DR/CC- -------> pin 23 (gnd)
DR/CC+ -------> pin 6 (z direction)
Now the motor still turns in only one direction but now counter-clockwise. The once 4.7v between DR/CC- and DR/CC+ is now 1.97v (perhaps 1.97v is not enough to trigger)
If I disconnect the CW- from pin 22 (gnd) there is no movement at all and the voltage between DR/CC- and DR/CC+ goes back up to 4.7v
If I reconnect CW- to pin 22 (gnd) and instead disconnect DR/CC- from pin 23 (gnd) the motor only turns counter-clockwise just as before
If I disconnect the DR/CC+ and - all together it goes back to clockwise movement only.
In fact the only way I can get the motor to change directions is to touch or untouch the DR/CC+ wire to the terminal of pin 6 (z direction) with the DR/CC- disconnected.
I suspect this issue has something to do with the reference grounds CW- and DR/CC- being different or not being able to be tied together. Or perhaps the voltage drop of DR/CC+ down to 1.97v when the CW- is connected to ground is preventing the logic from triggering.
Anybody recognize what's going on here?
Very much appreciated. I'm very close, just can't get the direction straightened out. Thanks!