Hi,
at the current time, and to my knowledge, Vital Systems HiCon board is the only Mach4 controller that has full blown realtime THC.
The UC100 does not support THC in Mach4 but does in Mach3.
it seems Mach4 doesn't support THC or even basic Up/Down inputs
This is incorrect, Mach4 has THC signals defined but requires the controller to implement it in hardware, at this time the HiCon.
There has been talk that because of the rapidity that Mach4 cycles that a programmatic THC solution is feasible, albeit somewhat slower than realtime
THC like that of the HiCon. No announcement regarding the release of such a solution and/or the hardware support that would be required for it has been
made by NFS.
One of the most recent updates from Microsoft for Windows 10 has presented a problem for Mach3. A patch for Mach3 has been released.
Development on Mach3 ceased five years ago and there has been no indication that NFS are inclined to revise that policy, for that reason
Mach4 is the preferred solution for the future.
Craig