I have a TD A120. Have you got the full automation Interface with divided voltage?
It seems a shame to have such a high quality machine controlled by such a crappy board. Working to a budget, might I suggest you consider a Mesa 7i96 ethernet board and a Mesa THCAD-10 combined the LinuxCNC Plasmac controller? See: PlasmaC User Guide
That will set you back $188 for the hardware but you will need stepper controllers. I have had good results with the Longs Motor DM542A https://www.ebay.com/itm/Nema23-Step...YAAOSwduxbk2Zs at about $30 each. I get 21 metres per minute out of them. The beauty of the 7i96 is that it has relays built in. Normally, you'd use a 24 volt (field power) and a 5 volt (logic) power supply. This will give you a high performance system with a fantastic THC built right into LinuxCNC.
The THCAD is a voltage to frequency converter designed for the harsh plasma environment, It reads the torch voltage and converts it to a frequency which is read by the 7i96 encoder input and we convert the frequency back to a voltage for Linuxcnc to mange the THC. LinuxCNC uses its sophisticated PID based controls and its external offsets feature that offsets the Z axis position based on the torch voltage.