How do you controlling a stepper motor

[pj84]

I want to control a stepper that is lifting a scissors lift but I want to calibrate it to different height enter in the heights into memory and then recall when necessary.

[jgb@bpa]

Not sure if you were looking for electrical help or programming help. If you want more details you could reply to the thread....

You need a stepper motor controller. This is an electronic circuit. They can probably be found with a web search. The range in prices from $50 to $1000 or more. Or you can build one using componants from National Semiconductor or Allegro or Texas Instruments or other chip makers.

Depending on motor configuration, you can have a unipolar (6 wires, 3 wires per phase) or bipolar system (4 wires, 2 wires per phase). If you don't have instructions with your motor, you can figure out phasing with an ohmmeter.

Usually the controller has a square-wave input and a direction input. Sometimes some other inputs. Usually there is one step (or even one microstep, depending on the controller) per rising edge. Sometimes they have an analog speed input, but this kind of controller is probably not right for your application.

You can count steps in one direction. The stepper controller takes care of powering the windings to make the motor turn round. Then count steps back. Unless you have stalled the motor, the motor steps are very repeatable in location. If you remember how many steps from some reference point (i.e. all the way in one direction, say), you can save the position reference and come back to the location by counting up or down until your current position reference matched your saved reference.

Hope this helps some.

[Dan_Quinn]

Hi PJ84,

You definitely came to the right people on this one. We provide a variety of motion control solutions, particularly for stepper motor control. What equipment do you have so far? a motor? a controller? a drive?

We offer stepper control boards, as well as boards that con control both stepper and servo motors. We also provide the 7604 stepper motor drive that can cable directly to your PCI or PXI motion controller, or the UMI connection boxes that allow you to connect to a 3rd party drive.

Configuring the motion is actually pretty easy. With the driver software we provide (for free!) you can configure your board in Measurement and Automation explorer, and even test out the moves on each axis. From there, you can program the moves like in your application through LabVIEW, C, Visual Basic, or any of the other supported languages for NI-Motion.

You might want to give us a call, or we could have one of our field engineers come by your site to help you get started up (that's free too)!

Drop us a line with any further specific questions.

Regards,

Dan
National Instruments