Stepper controller with analog command signal and feedback

I want to make a linear actuator using a stepper motor and leadscrew. I need the controller to accept an analog signal for the setpoint position, and take a potentiometer signal for the current position. The feedback signal could be something else, like an encoder, but has to be capable of multiple revolutions and be able to report absolute position upon power up (which I’m not sure an encoder can do??). Is there a motor controller for this? Thanks for any response.


We do not have a motor controller that has the kinds of features you’re looking for. By the way, if you’re having to do closed-loop position feedback anyway, why are you using a stepper motor? Something like our jrk motor controller with feedback could do everything else you’re describing except for the stepper motor part. There are multiple-turn potentiometers that can take care of that part of your requirement; you might also be able to use a linear potentiometer measuring your output rod position.

- Jan

First of all, thanks for the reply. I chose stepper because I know there is a very compact design available which uses the rotor as a nut for a leadscrew (see Hayden Switch or HSI). Advantage over dc motor is no gearbox, and leadscrew coupling. Or do you have, or know of, a compact linear actuator using a dc motor? The stroke length is less than an inch.

The jrk controller looks like it would work – I see the analog feedback and well as analog control signal. Do you know of another manufacturer’s stepper controller that has these features? Or can I use one of your programmable controllers in conjunction with a standard stepper motor driver board?

Thanks in advance.

Unfortunately, the jrks cannot readily be coupled with a stepper motor driver, and I don’t know of any such controllers from other manufacturers.

- Jan

Sorry, I missed your last question. Yes, something like our Orangutan robot controllers could be used with our stepper motor drivers to do what you’re looking for. If you don’t need the microstepping or current limiting features, you could even use the built-in motor drivers to drive the stepper directly. However, working with these controllers is not necessarily easy if you don’t have any experience with microcontrollers.

- Jan

So, I could use your A4983 stepper driver, with the step and dir lines connected to the orangutan, correct? Or if I connect the stepper motor directly to the orangutan, where would I connect the two phases of the motor? To the motor 1 and 2 outputs? If connected directly to the orangutan, is there some easy output commands, or would I have to figure out the proper switching sequence to the motor? I’m guessing it would be much easier to use the stepper drive board.

I’m not afraid to try some programming on the microcontroller. My application is pretty simple–I just want the actuator position to follow the analog input, and use position feedback to ensure that it is tracking properly. I appreciate your comments.

If you used the Orangutan motor drivers, you would hook up one coil per regular motor output, and you would need to generate the step sequence yourself (that’s not necessarily that difficult if you don’t need to go fast). Using the dedicated driver chip should be a bit easier, and it is mostly just that step and direction interface, though you might want to look at some of the other I/O lines.

- Jan