Custom macros for the Centroid Acorn

My machine has 2 speed ranges and a proper variable speed motor / VFD. On the original system, the high speed range was 1000-6000rpm and the lower range was something like 20-1000rpm. Unlike the Bridgeport arrangement with its combination belt / gear drive, the two stage gear reduction does not cause a reversal of direction between ranges. That's an improvement to be thankful for.

The gear selection mechanism uses a rotary pneumatic actuator to shift ranges and I'd like the range selection to happen automatically. There are 2 spare relay outputs on the Acorn, so I should be able to drive the (24V) pneumatic solenoids with them, assuming I can find enough current in the existing power supply - or add another one if necessary.

It looks as if the M3 and M4 macros are easy to customise but it becomes rapidly clear that the whole software thing is going to be a bit of a challenge. They talk about 2 main software elements - the PC-resident "CNC12" (user GUI and top level controls) and what they like to call the "PLC" software which appears to reside in the Beagle Bone Green (the brains of the actual Acorn unit). I have no idea why they call it "PLC", as there isn't a PLC to be found. And even if they were using a high level (text) programming language to implement a PLC-like environment, that would normally be a version of Pascal. The Centroid language is nothing like that. Looking at the PLC "compiler" program that was installed when I loaded up their system, it seems they developed their own compiler, so presumably they have also made up their own syntax, acronyms, conventions etc.

The previous products (currently the "Oak" and "All In One DC" seem to use a DSP (TMS320 perhaps?), which is a long way from being a PLC or an FPGA. However, there appear to be several large packages, so I wonder if one of them is an FPGA or CPLD.

I'm realising that the gear "control" is passive on the Centroid by default - in other words it likes to be told what gear it's in (using an input), rather than be the daddy and actually select the correct gear. That's a bit shit in a computer controlled machine. Anyway, let's live with it for now...