I'm working on a project where it would be prefferable to use one stepper driver to run 2, possibly 4, stepper motors seperately using relays. The plan is that the steppers would start rotating one after the other (first stepper starts rotating, others turned off-->second stepper starts rotating, other turned off and so on...). I am using the AccelStepper library and I have the acceleration and deceleration code written as I want my steppers to smoothly transition from speed to stop.
The materials I have/ am planning on using are DM420 2H microstep driver (https://www.exp-tech.de/module/motorsteuerung/schrittmotoren/9341/dm420-stepper-motor-driver), NEMA 17 ST4118M1404-A stepper motors from Nanotec (ST4118 - Schrittmotor – NEMA 17 | NANOTEC) and an 8 Channel, 5 V, SRD-05VDC-SL-C relay module (DEBO RELAIS 8CH: Entwicklerboards - Relais-Modul, 8 Channel, 5 V, SRD-05VDC-SL-C bei reichelt elektronik). If anyone has experience with this, please share. As I am fairly new to the arduino world and electronics in general, I would kindly ask for help with wiring and assembly if possible.
Using relays to drive stepper motors is not the way to go. In fact, I do not know how you would control a stepper with a relay or relays. Modern stepper drivers can provide coil current control, micro stepping and high efficiency for low cost. A stepper driver per motor is the most efficient. The Pololu DRV8825 drivers would be a good match for your motors. They are also available on Ebay and other sites.
Make sure to set the coil current as shown in the instructions on the Pololu page.
That destructables link is NOT using a stepper motor driver, but abusing an L293D brushed DC motor driver.
Stackexchange is using a true stepper driver, but I've seen many warnings not to disconnect motor wires from this A4988 chip, because it could instantly destroy it.
Transistors instead of relay contacts could make a difference, but construction seems weird.
Large stepper controllers could be better protected, but trying that out is your call.
Leo..
Post#1 links to a driver that's powerful enough for the stepper you're using.
And there are CNC shields available that you can plug in four of those boards, for four steppers.
Leo..
Are the steppers mechanically driving a load that relies on the stepper motor being locked in position when not moving?
Driving a stepper to a position is one thing, needing it to hold that position is another.
When a stepper stops, it does not necessarily have drive current removed.
Use a driver for each stepper and it will simplify your project.
Hi Tom,
The steppers are used for stirring so they just need to rotate. Nothing fancy, no load. I have used one driver(the one in the original post) for 4 series connected steppers and it works as it should. Could I achieve the same with the DRV8825?
matran77:
Hi Tom,
The steppers are used for stirring so they just need to rotate. Nothing fancy, no load. I have used one driver(the one in the original post) for 4 series connected steppers and it works as it should. Could I achieve the same with the DRV8825?
What are the specs of the steppers?
Can you post a diagram showing how you want to connect the steppers?
Why steppers for stirrers?
Tom....
Hi, sorry for the delayed response.
Tom: The steppers are 1,7VDC & 1,4A/phase. The documentation is in the attachments. For the wiring: first stepper is connected to second stepper with wires RED (to YELLOW on second stepper ) and BROWN (to ORANGE on second stepper). The second to third, third to fourth by the same pattern. In the end the steppers are arranged in a circle with first stepper having 2 free wires, YELLOW and ORANGE & the fourth stepper having 2 free wires, RED and BROWN. So everything works as it should with the current driver we are using. Since the DRV8825 is cheaper, my question is if it could also do the same job as the DM420 driver. The choice of steppers for stirrers was not my idea, but we have to work with what we have.
Mark: Understandable. My understanding is that it should work if I also put a relay before the dirver and turn it off between motor switches?
