clunks / missing steps - DM856 and single pulse operation

[irving2008]

Is that trace from a time when it misbehaved? How sure are you that it's not contact bounce on the switch? Where is the driver input ground tied back to? Is the driver opto-isolated and are you sure the PIC is driving it hard enough?

[dsc]

Hi Irving,

the trace shows any pulse generated by the PIC, I've looked at traces of randomly captured pulses and they are all the same. De-bounce is done on all switches, so they behave properly without any ringing etc.

From the manual the connections look like this:



I'm not sure what current consumptions the inputs have, but since it's all opto-isolated, I'm guessing the amount of current needed to drive them is not high. Looking at the above, the PUL+ is tied staight into the PIC output and PUL- is connected to 0VDC which is common to the PIC as well.

I can post a video later on to show how the 'clunking' looks like.

Regards,
T.

[irving2008]

so you're driving the input to the stepper driver direct from a PIC output? What PIC are you using?

[dsc]

Indeed, although I've just noticed that I'm using the pins on the PIC as source and the diagram in the manual shows the controller pins as sink ie. PUL+ connected to 5VDC and PUL- to the pin on the controller. I have it the other way around, PUL+ connected to the pin (which goes high to generate pulse) and PUL- to 0VDC. I'll swap it around and do a test.

I'm using PIC16F887 to control the DM856.

Regards,
T.