Can you tell me the ideal voltage and frequency for driving the SY42STH38-1684A. We are losing steps need to reduce this problem. We are using an md32a driver. We also have md20b drivers if that would work better.


The ideal parameters to drive any stepper motor will depend on your specific setup and application. If you post more about your current setup, like the current voltage and speed you are driving your motor at and what load you have on it, I would be glad to help you troubleshoot. A video of your setup that shows the issue might be particularly helpful.


Hey Claire,

Thanks for the feedback. We are presently using 9V. It draws about a quarter amp with both motors are engaged. We have it set for 1/16 mirco stepping. It is a two axis plotter as you can see in the attached video and photos. We are not even sure the problem is in the hardware, but just wanted to get best-practice suggestions for frequency, voltage and micro stepping given our set up.


Hi, Sam.

From the video, it looks like your motor is moving pretty well and you are fine-tuning. It is definitely possible that, as you mentioned, the issue is with the mechanical setup rather than the driver, but there are a few things we can check.

What is the current limit or Vref voltage of the driver set to? It does not look like you are stepping the motor very fast, but you can look at the pull out torque curve in the motor’s datasheet to get a general sense of how fast it can go with how much torque. If you compare your torque and speed to that graph and are close to the limit, you could experiment with increasing the motor voltage. If you have a scope with a current probe, you could also monitor the waveform of one coil and look for skipped steps.