Thank you for the M4 code valhallaCNC. I seem to still be having issues getting CCW functionality working. It was working with ModbusEZ, but doesn't seem to be with Modbus Master. Looking over the Huanyang GT manual I can see Address 1000H (aka 4096) can have values of 1-8. 1 = CW/FWD, 2 = CCW/REV, 5 = STOP.
I think I have the Modbus Master Function Settings done correctly per your instructions:
I can start and stop and the values move correctly from 1 (CW) to 5 (STOP).
But pressing the "SPINDLE CCW" button on the main screen or sending an M4 over MDI doesn't start the spindle in reverse like it did when I used to use ModbusEZ. And if I try and force the cell to 2 in the Modbus Master to get it to go in reverse it doesn't work.
I appreciate any advice you can provide.