I need to slave the A drive to my duel X motors How?

Machine: K40 parts and a 1200 x1200 build with Cohesion3d board

Firmware: _Smoothie

Problem/ Question: _ So I am building a new laser with the parts from my k40 and I did a duel x and I need to slave the other motor and would like to know how to do that?laser1

Hi Chris, for a CO2 laser it is a bad idea to have 2 separate motors drive a single axis - if they get out of sync it will send the beam where you really do not want it to go. A single motor with a shaft driving the rails on both ends is the correct way to do it.

That said, it is possible to slave A to Y driver if you need 2 motors. You would need to check the size of the motors to be sure it would work. Though as stated, we do not recommend doing this for a CO2 laser.

ok I under stand the risk of Skipping a step on one motor Thanks for the heads up. So How do I slave the a to the y . I have it working now with the both motors wired together I also set the amps to 1.2 on all three motors. Would it be better on the board to slave them instead of wiring together?

Hi Chris, we are currently experimenting with a similar setup: running two stepper motors parallel on a single axis. To minimize the risk pointed out by Pete we have done the following:

  • matching motors & stepper drivers (both have their own driver)
  • setting up the signal from the board Y axis into a parallel layout on the motors. This way the software sees it as a single output and you can never have any alignment issues by software failures.
  • we use closed loop steppers to also minimize the risk on missing steps

Okay, let’s take this step by step.

Step 1. Locate your motor specifications and provide them here. Knowing the specs of the motors you are using will help greatly in providing advice on the correct way of doing things.

We should note that the maximum per-driver current on the LaserBoard is 1.2 amps RMS. There’s a bit more about that here:

Step 2. If the combined current of your motors is within the maximum per-driver current, you could hook them both up in parallel to the Y driver.

Step 3. Otherwise If the combined current of your motors is greater than the maximum per-driver current you can use two separate drivers. Here is how to do that:

To slave the A to the Y you’ll need to carefully remove 3 jumpers and move them over one position to the left.

The photo below shows how the LaserBoard is shipped. Just power everything down, shift all 3 jumpers to the left, and then the A driver will be slaved to Y.

This will allow you to provide higher amperage to each motor if needed. (Up to 1.2 amps RMS as mentioned above.)

If your two motors do not need higher amperage you can just connect them both to the Y driver in parallel as long as the current specs of the motor allow it.

Hopefully that all makes sense. Let us know the specs of your motors if you’d like us to check your decision.

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Thank you so much I just need the jumper config on the board. That was all I needed. You hit the nail on the head with this reply Thanks again.