How to generate Charge Pump signal with PMDX-424?

[iserban99]

Hello,

I have a CNC router (Heiz High-Z S-1000 T) equipped with a Zero3 controller and I'm replacing the old motion control and software (WinPC-NC USB) with PMDX-242 and Mach4.

https://www.cncstepusa.com/cnc-control-zero3/
https://lewetz.de/en/products/winpc-nc/winusb

The problem is that Zero3 controller needs a Watchdog/Charge Pump signal on LPT1.16 and PMDX-424 does not support a "Charge Pump" feature. The frequency of Charge Pump signal generated by WinPC-NC USB is 12.5 kHz.
I'm thinking of generating this signal from Mach4, using a Lua script, but the signal should be toggled every 40 us and don't want my routine to disturb Mach4 main routine.

How can I fix this?

A similar issue, but with another solution (for PMDX-411) is here:
https://www.machsupport.com/forum/index.php?action=printpage;topic=31446.0

Thank you.

Serban

[12strings]

While this could hypothetically be generated by a Lua script or the PMC, there is a basic limitation in the USB communications that will limit this.  USB 2.0 has a basic frame rate of 1 KHz.  This is therefore also the absolute maximum signal update rate.  So a 500 Hz signal is the highest frequency you could ever hope to generate using code running in Mach4.  And this totally ignores any communication overhead that the SmartBOB may impose.

It is not possible at this time to run two SmartBOBs at the same time.  Maybe something like a POKeys or other device just to generate the charge pump (presuming it can be used as an I/O only device and not as the "motion controller").  Or if you have a physical parallel port and can use the Mach4 parallel port driver (also only if it can be used as an I/O only device and not have to be the "motion controller").

Of if you are into programming, an Arduino or similar board could easily be programmed to take an "enabled" signal from the PMDX-424 and generate the charge pump signal.