[Pader]

I have, among others, just bought a cheap Chinese router/laser engraver controlled by grbl on an Arduino board. I am in the process of increasing the 320 x 160mm table size mechanically and using TB6600 Driver modules on larger stepper motors to provide the necessary extra power.

I also have a 4 Axis, stand alone controller. (TOPCNC TC55H)

Is it feasible to build a circuit that will allow me to switch the stepper control signals between the grbl based Arduino and the stand alone controller so I have the choice of machine control? Both the Arduino board and the controller use a 24V power supply.

Also, slightly off topic, does anyone have a source for operating instructions for the TOPCNC TC55H Contoller? I have searched both google and Youtube trying to find a tutorial.

[dharmic]

Sure you could do it electronically. Use a FET as a switch to block each controller output from pulling the appropriate driver line low. Yeah, that's a lot of FETs. There may be a chip which gangs them up too. If you HAVE to. Alternatively, that kind of interchangeability can be done easily by ganging the driver inputs into a connector and having a mating connector for each controller, just plug in the one you want.