[Deluminati]

Hi rich

You seem like the best person to ask regarding a plan i have for my machine. Basically i have a pc turn 50 all intact with fanuc controller, and i have the spindle driver, stepper driver, axis controller and rs485 card for a pc mill 50, my plan was to swap the stepper driver boards because the mill one obviously has an extra axis, is it as simple as that to get it running?

Hi - I have a PC mill 50 that I've got working with Linuxcnc - the steppers, drivers, spindle and VFD are all as standard - obviously the main controller card is replaced by the computer running linuxcnc (mini-itx inside the control box). I put together a simple circuit to convert the 3.3v logic input/output of the computer to the differential drive required by the mill. The differential inputs to the drivers and VFD are 0v/5v - I used 26ls31 and 26ls32 chips to do the conversion for me.
There are pinouts earlier in this thread - to complete the story:
Axis:
3x axis are driven by differential 0v/5v logic.
E-achse doesn't seem to do anything (maybe it is enable, but leaving it floating is sufficient. Don't know, but works without it)
SR X,Y,Z is a rotation sync pulse, but I'm not using it
The connector doesn't have a ground, so you have to make sure the connection is grounded somewhere (grounding is important anyway)

Spindle:
Spindle runs as PDM, with 0v/5v differential clock input driving speed
Differential 0v/5v dir drives direction
Differential 0v/5v phase and index outputs (input to the computer, SR+/- and NI +/-) can be used for rpm - I've only used the index pulse for rpm so far, but it works okay like this.
0v/5v Differential enable (E/AMD +/-) used to start/stop spindle. IMPORTANT - this triggers on the rising/falling edge, so if you just put a circuit together with these driven from the voltage rails it won't work if the circuit is on before the mill is switched on. But you might as well drive it from the computer using spindle enable. Also, I think this is different from the other inputs, in that you can enable the spindle with a rising edge on the +ve input OR a falling edge on the -ve input - but I'm not sure and I'm driving it using a differential signal anyway.
Don't know what IAMD does - guess it is a current feedback, but all works okay without it connected.

limit switches - normal open switches, so connect in using normal circuitry (ie, drive high using a resistor to 5v rail, then activating switch takes input low).

If anyone is interested, I'll put some pictures together, example circuit, etc.

I've also got a couple of interface PCBs spare as I had to order a minimum quantity - if anyone is interested I could send one for a contribution to the pcb printing fund - it isn't particularly elegant in layout, but works fine.