Slaved Axis setup replacing Richauto with PMDX126 and Mach4

[Mike Abbott]

I've recently gotten my new CNC router and had every intention of replacing the Richauto DSP controller with a PMDX126/ESS/Mach4 mostly because I understand Mach4 much better and am used to it.  This had the added benefit of getting rid of a 24v standalone PSU in the electronics cabinet and simply driving it all off the 220v mains.  The PMDX126 makes all that quite simply so thanks for the nice board.

This machine has 4 Leadshine DMA860H connected to 4 Nema 34 steppers.  X and Z axis were pretty straight forward for the migration but the Y axis is the gantry with a typical Y1 and Y2 motor config.  The way the Richauto was connected up was with a single +5v, Step, Dir connector to the Y1 driver and the Y2 driver simply daisy chained from the Y1 driver.

I've replicated everything on the PMDX126 with the Y outputs on pins 3,4 and it certainly seems to work just fine (so Mach is only aware of the 3 motors, no slave setup in the software).

I've read another post with a somewhat similar question but different Leadshine drivers and there was some concern about the necessary current of the output signal pins.  Is this something I should simply wire to include the Y2 drive as a slave or is the daisy chain a good solution.  Seems like a sound way to keep the 2 drivers in sync but I've not run the machine for any duration and have just tested things so far, just trying to avoid future head scratching.

To be honest, I'd never even considered doing a daisy chain setup so got me thinking for sure.

Mike

[Mike Abbott]

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[12strings]

The PMDX-126 is spec'd to source/sink 16mA per output signal.  It looks like the Leadshine drives spec input current from something like 7ma (min) to 16mA (max).  Since you've been running the machine (some) with the PMD-126 driving two Leadshine drivers from a single pair of outputs, obviously the 16mA requirement isn't happening at the temperatures you are running.

But... it would be better to run each Leadshine from its own set of step/dir signals.  First off, this guarantees that the PMDX-126 will always be able to drive the Leadshine inputs.  More importantly, it allows you the OPTION of having Mach4/ESS do gantry squaring.  That is if the ESS supports that under Mach4 - I don't know.  But if it doesn't support it now, it should support it some time in the future.  For now you CAN configure Mach4 for "slaved" axis, which means multiple motors driving the same axis, and use a single home switch for both motors.

Curiosity, since we are on the PMDX forums - why did you choose the ESS instead of one of the PMDX SmartBOB boards?