Linear actuator and motor controller with feedback

I’m revisiting a project to automate a lab procedure, and I plan to use the linear actuator with Feedback LACT10P-12V-20 hooked up to Jrk 21 V3. I have no electronics knowledge, so I’ll keep it simple for now - I will control the linear actuator by either a momentary forward/reverse switch or a joystick.

  1. If I use a simple forward/reverse switch, does it mean I can’t adjust the speed of the actuator without connecting to a PC, or is there another set of pins for a second analogue input?
  2. What power supply should I use for this setup? Do I need a fuse somewhere in there?
  3. The linear actuator will perform small extensions (up to a few mm) and retractions repeatedly under load with about 0.5 second time lag in between. Does the duty cycle allow for that?
    Many Thanks!

Hello, drosologo.

You didn’t say it explicitly, but I’m going to assume you want to connect the actuator’s feedback potentiometer to the jrk so the jrk knows the position of the actuator and you can control that position rather than just controlling the speed of the actuator. The alternative is to leave the actuator’s feedback potentiometer disconnected and just use the jrk to control the speed of the motor.

You say you’re want to automate a lab procedure, but you are considering having a switch or joystick and that usually means a human is present. What exactly are you trying to do?

You would need to set the jrk’s Input Mode to “Analog” for your switch to have any affect, and in that mode the jrk’s motion can’t be controlled from the PC. There are only two analog inputs on the jrk: one for the input voltage and one for the feedback voltage from your actuator’s potentiometer.

You should decide what voltage you want to run your system at and then choose a power supply that can deliver more current than your system will draw at that voltage. The actuators are designed to run at 12 V and the jrk 21v3 can operate at that voltage, so 12 V is a reasonable choice. The actuator’s stall current at 12 V is 10 A, but the jrk 21v3 can only deliver 3 A continuously and 5 A peak. The jrk 21v3’s motor driver chip has built-in current limiting, so you’ll probably be OK without a fuse, but putting a 3 A fuse in your system would be okay especially if you think there is a possibility for the actuator to be stalled for long periods of time. I’m not sure whether it’s better to put the fuse between the jrk and the power supply or between the jrk and the actuator and I’m not sure if it makes a difference.

I’m not sure what you mean by “does the duty cycle allow for that”, so I’ll just try to tell you if this goal is possible in general. You said there is a 0.5 lag time between the extensions and retractions but you didn’t say how long you want the extensions or retractions to take. I think the jrk and actuator will be capable of something like this, but you have left out a lot of important details. How will you be controlling this movement? Will there be a human operator wiggling a joystick back and forth, or a computer program or microcontroller sending commands to the jrk? How precise do the endpoints of this motion need to be? How precise does the timing need to be?