Linear actuator, motor controller and labview. Connection

I have a 12VDC linear actuator (potentiometer built in) connected to power and Jrk 21v3 USB Motor Controller with Feedback. The USB motor controller connects to the computer through USB, actuator’s feedback wires connect to the motor controller.

Establishing connection between the motor controller and labview.

What I have done so far:

I installed drivers to the motor controller and windows detects it. NI MAX detects my motor controller, but for some reason, when i try to access it through daq assistant in labview it doesnt see it. I also tried accessing it through VISA with no results…

Does anyone know what should i do for labview to see the motor controller?


Hello, Peter.

I don’t know much Labview, but I know that other customers have had success controlling our products from LabView by using some sort of serial port control that allows them to calculate and send bytes on a serial port. This post shows how to control the Maestro using LabView, and it might be useful to you:

Please note that the Maestro has a different serial protocol than the jrk, so you would have to change the bytes that are being sent. You should also set your jrk’s input mode to “Serial” and set its serial mode to “USB Dual Port”.


I had success using this VI but am now having trouble sending my servo to the maximum and minimum angles. From what I understand about my servo, I can set the position from 0-254 but when I do so, I only get about 45 degrees in rotation. Any idea what I am doing wrong?


To get the maximum range out of your servo, you will need to set the Maestro’s “Min” and “Max” parameters for that channel correctly. We have instructions on how to do that in an FAQ entitled “How do I use my Maestro servo controller to get the maximum possible range of motion from my servo?” which you can find on this page:

After you do that, you should be able to get a wide range of motion out of your servo when you control in the Maestro Control Center’s status tab. Since the VI is using the Mini SSC command, the mapping of 8-bit values to higher-resolution servo targets is determined by the “8-bit Neutral” and “8-bit Range” settings in the Maestro Control center and you would need to adjust those two settings as well.