Two Tic T500s Coordinated Homing

I’m working on a linear rail system that will require two stepper motors to run in parallels with only PWM input and stop switches for control. One obvious solution is to run both motors in parallel from the same controller and use a single stop switch for startup homing. However if the two leadscrews were to become misaligned, homing would not bring them back into alignment. Another option would be to have two T500 controllers, one controlling each stepper motor with independent stop switches. But my concern would be that at startup one could start homing before the other. Is there a way to synchronize two tic controllers without the addition of another controller like an Arduino?


The scope of your setup isn’t clear to me (i.e. where is your PWM signal coming from and do you also have a DIR signal?), however, it sounds like you might be talking about using the Tic in STEP/DIR mode with the PWM signal as the STEP input; please note that the STEP and DIR pins on the Tic are connected directly to the STEP and DIR inputs on the on-board stepper motor driver IC, so limit switches will not work with a Tic configured for STEP/DIR control. So that setup would not work the way you described and you still wouldn’t be able to control the two Tics independently if you’re using a single input signal for both of them.

The method of running both motors from a single stepper motor driver (making sure to properly account for the voltage and current per phase depending on if you’re connecting them in parallel or series) is probably the most straight forward way to have them always move together. As you noted, you will not be able to run them independently to re-sync them if things get misaligned; however, there are a couple crude methods such as de-energizing the system and (slowly) moving them back into alignment by hand or running the stepper motors into a physical limit (preferably at a lower current limit).

If I misunderstood the setup you’re describing (e.g. you meant an RC signal when you said PWM), please post more details about your setup and I would be happy to see if I have any additional suggestions.