cmarcus Posted August 17, 2012 Report Share Posted August 17, 2012 Hello All, I have a simple 1-axis stepper motor application that I'd like to use a Vision 130-33-T2 PLC and control the motor using the +24V DC PWM outputs. The problem I'm having is finding a decent low cost motor controller that supports sourcing inputs for step control. I seem to keep coming across ones that only accept sinking inputs or the fully programmable ones. So I guess my question is two fold: 1) Does anyone know any low cost stepper conrollers that accept the +24 VDC pulse train from the PWM outputs on the PLC. 2) Is there a simple way to convert the Unitronics output to sinking? Thanks in advance, Quote Link to comment Share on other sites More sharing options...
MVP 2021 Joe Tauser Posted August 17, 2012 MVP 2021 Report Share Posted August 17, 2012 First off, you don't want to use a -T2. You'll find the outputs won't be fast enough. Depending on your I/O needs, a -TR20 or -TR34 is a much better choice. Been there. The high speed outputs on the -TR20 and -TR34 are NPN (sinking) out of the box. They go to 200 kHz which should be way faster than you need. If you look at the actual circuit for a stepper control, it is usually an isolated opto-coupler and really doesn't care whether the output is sinking or sourcing; it's just a matter of how you hook it up. You want to limit your current to about 10 ma, so if you put a 2.2K resistor in series between your 24V supply and the (+) stepper input you can drop the voltage down to the 5V the control is looking for. Connect the (-) stepper input to the PLC output and you've completed the circuit. As far as low cost stepper controls, I've never seen any cheaper than these: http://www.mpja.com/Step-Motor-Driver-5A-Max-Wide-Range-CW250/productinfo/17452+MS/ This unit is limited on its micro-stepping options. This may or may not matter to you. If you need precise positioning (< 1.8 deg), you need to use micro-stepping and hence a higher frequency to drive it at a decent speed If you look at its little brother (3A rated) on the website it has many more micro-stepping choices. Joe T. Quote Link to comment Share on other sites More sharing options...
cmarcus Posted August 22, 2012 Author Report Share Posted August 22, 2012 Hi Joe, Thank you for the reply. This information was very valuable. Much Appreciated, -Chris Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.