Hello,
I am trying to control multiple stepper motors on a relatively small budget for a class project. I will worry about the issue of multiple motors later; for now, I’d like advice on controlling a single motor. I don’t need fine control of position or anything, I only need to control the rpm’s; I chose stepper motors because the application requires large torque at relatively small rpm’s, and most of the DC motors I saw didn’t fit the requirements. I have already acquired several bipolar 20x30mm motors (Pololu item# 1204) and some A4983 controllers (Pololu item# 1201). I have multiple accessories in the lab, including several adjustable power supplies (Agilent E3631A), function generators (BK Precision 4010A, output from 0-6V), and various multimeters, filters, oscilloscopes, breadboards and wires. I was told that I could use the function generator to run the stepper motor with the A4983 board. The wiring diagram for the A4983 shows a continuous voltage supply for motor, and a supply for both the A4983 and an unspecified microcontroller(which I don’t have). Currently, I have the single power supply providing 9V to the motor port and (through a resistor) 4.5V to the board port. How can I use my existing function generator, power supply, etc. to provide the STEP and DIR signals? I have access to L298 and L297 chips from another student who said he used them for stepper motor control, would they be of use? I have never used stepper motors before, so any advice or a tutorial you can offer would be extremely helpful.
I am not interested in using digital code, PC interfaces, etc. While convenient, ordering them is out of my budget and time restrictions.
Thank you,
Andrew
Hello, Andrew,
I didn’t notice your post before replying to your email asking this question, so here is the text of my reply for the benefit of other readers. Feel free to continue the discussion here. (In the future, though, please do not contact us multiple ways without mentioning that you have done so.)
The easiest way for you to run your stepper motor is to tie the A4983’s DIR input either high or low, and then use the function generator to provide a low frequency square wave on the STEP input (each rising edge will advance the motor one step). It is a good idea to add a 1k resistor between the function generator and the stepper driver to protect it in case the voltages do not match. You can find the details on the operation of the A4983 in its datasheet, available from the Resources tab of the product page:
pololu.com/catalog/product/1201/resources
By the way, using a resistor is a very bad way to produce your logic voltage and could easily damage the device. You should power it from a regulated supply, either by using another adjustable power supply to produce 5 V, or with a voltage regulator that steps your 9 V supply down to 5 V.
- Kevin