Need help with stp/dir signals to DYN4 drives. So close.

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!

I would send this info in an email to [email protected]. They were very helpful when I was setting up a DYN4 as a spindle motor.


John

Are you using the DMB4250-8B board? It is expecting the pins to be pulled low, like when connected to a parallel port on a computer. Is your machine a Syil?

Is your goal to run the DMM drives with the original controller? If so, you would be better to connect the controller directly to the DMM drives and eliminate the breakout board.

Thanks rcheli. I have been getting great support from Micheal at DMM but was just hoping to get some guidance this weekend.

Quote:

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Originally Posted by Jim Dawson

Are you using the DMB4250-8B board? It is expecting the pins to be pulled low, like when connected to a parallel port on a computer. Is your machine a Syil?

Is your goal to run the DMM drives with the original controller? If so, you would be better to connect the controller directly to the DMM drives and eliminate the breakout board.

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Not a Syil, it's a Mikini. Yes I wanted to use the original controller because it handles everything else (e-stop, limit switches, home switches, oil pump, coolant, lights, alarms, etc.) without have to rewire anything. I'm pretty sure they can be wired right into the drives, but if possible I wanted to keep all of the the motor signals confined into one parallel cable/port connection that goes through the DMM BOB. If that can't be done, I'll wire directly to the drives. I'd like to explore this way first given my control cabinet layout and the complexities of the existing hardware, cable routing, etc.. Seems like it should be doable without too much trouble. So do you think I need to add pull-down resistors or an isolator?

Thanks for your input!

I'm going to stick my neck out here a bit and say that you need to invert the logic to the parallel pins. The output from the controller seems to be PNP and the parallel port is expecting NPN. It's been about 10 years since I designed a board like that, but there are 74xxxx chips that would do what you want, inverting output.

On the other hand, the DMB4250-8B board has inputs and outputs for all of your switches, sensors, and other devices.

I agree, Michael provides great support, has helped me over a couple of rough spots.