stepper motor control

[azzrock]

hi everyone. I have a servo motor that i would like to get running in both forward and reverse. at one speed.
its a little 6 wire thing . is there an easy way to get it spinning the way i require?
253409253410253411

aaron

[Malibu]

G'day Aaron,
If you're looking for a way to hook it up to battery and flick a switch to make it run, there's no easy way to do that.
Steppers require a certain sequence to make them 'turn'... or step, because they have poled magnets that need to be energised in one position, then energised in the next position, etc, etc.
The only way (that I know of) to do it is use a stepper controller. Either a pre-built controller (try Homann Designs) or develop something of your own.
Maybe a pic micro with a H-bridge driver or there's plenty of stepper driver chips that can be used (the part numbers escape me at the moment) but they also need step control.

Hope this helps

[Humphrey9999]

As John said, they're fairly complicated to drive, compared to standard DC motors. Depends on your level of electronic knowledge/equipment.
A PC or microcontroller and suitable software/firmware are needed to control most drivers, providing speed and direction signals.
I've got a few Minebea motors laying around here. They're good quality.

Jaycar have a kit for a PC-controlled stepper driver. (Out of stock at the moment.)Also a book explaining the basics of stepper motors: -
Jaycar Electronics - Search Results for stepper motor controller (http://search.jaycar.com.au/search?w=stepper%20motor%20controller)


eBay is worth a look, too: -
stepper motor controller | eBay (http://www.ebay.com.au/sch/i.html?_odkw=stepper+motor&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313&_nkw=stepper+motor+controller&_sacat=0)


John - a couple of more common driver chips are the L297, L298N, L6219, L6208, L6228 and L8229.

[Malibu]

...a couple of more common driver chips are the L297, L298N, L6219, L6208, L6228 and L8229.

Ah yeah, thanks for the memory refresher. I think I was using the 297's many moons ago. If I remember correctly, they also had a firmware problem when it came to microstepping. It ended up being an even more complicated set of instructions to get it correctly stepping.
Good semi's though, much easier to use than designing a whole driver circuit!

[Humphrey9999]

Ah yeah, thanks for the memory refresher. I think I was using the 297's many moons ago. If I remember correctly, they also had a firmware problem when it came to microstepping. It ended up being an even more complicated set of instructions to get it correctly stepping.
Good semi's though, much easier to use than designing a whole driver circuit!

L298N's were my weapon-of-choice years ago, (I think I might have a couple here somewhere), but the L6xxx series are better all 'round. Lower losses, too, from memory.

Aaron, what were you planning to use the motor for?

[sjm]

I tend to favour the ULN2003, but that's only because I already have a reel of them...

[Humphrey9999]

Your's is a 23KM motor. I have the datasheet for a 23LM motor here in my collection. I've attached it in case it helps. Both are 6-wire, so the pinouts are probably the same. Easy to check with a multimeter. There are 2 isolated sets of 3 wires. One wire from each set is the common centre-tap and the other two are attached to the ends of the coil.

sjm - ULN2003s and 2803s are good drivers and I keep some here myself for solenoids, driving power transistors etc, but the dedicated stepper driver chips have a few extra useful functions/features, making them easier to use. They also require less micro pins.

[Malibu]

L298N's were my weapon-of-choice years ago

You're right... I just had a look at one of mine that is kicking around in the junk box. It's a 298N. My memory must be getting dim along with my eye sight :B

[sjm]

sjm - ULN2003s and 2803s are good drivers and I keep some here myself for solenoids, driving power transistors etc, but the dedicated stepper driver chips have a few extra useful functions/features, making them easier to use. They also require less micro pins.

Very true. But when buying parts in lots of 2500, I tend to go for things I can use for multiple purposes, rather than something I can only use for one specific task.

[Humphrey9999]

Very true. But when buying parts in lots of 2500, I tend to go for things I can use for multiple purposes, rather than something I can only use for one specific task.

Sounds fair enough to me.

Thought I'd add - provided only a very small motor is being driven due to their current limitations. They can get hot really fast, too, even well within ratings, especially if a coil has to be constantly energised for braking/locking. They're not intended for a heatsink, but you can tack one on with heat-transfer adhesive, but it doesn't help a lot. Been there, done that.

[RayG]

Hi Aaron,

You can get all you need on ebay pretty cheap, first you need a power supply, then a step generator and finally a motor driver.

Not sure what power you need, but if 12v is sufficient then there are plenty of options, like an old PC power supply for example, will provide the 12V for the motor, and 5v for the generator logic

The step generator provides the pulses needed for the motor driver most have forward/reverse switching and speed control. here's one for $11.43 incl free shipping

Stepper motor Pulse Signal Generator module/Speed Regulator /driver controller | eBay (http://www.ebay.com.au/itm/Stepper-motor-Pulse-Signal-Generator-module-Speed-Regulator-driver-controller-/181072386381?pt=LH_DefaultDomain_0&hash=item2a28c1594d&_uhb=1#ht_2173wt_1165)

Now you need a motor driver... these are as cheap as chips on ebay... this one is $9.99

L298N Dual H Bridge DC stepper Motor Driver Controller module Board for robot | eBay (http://www.ebay.com.au/itm/L298N-Dual-H-Bridge-DC-stepper-Motor-Driver-Controller-module-Board-for-robot-/300828412153?pt=AU_B_I_Electrical_Test_Equipment&hash=item460ac548f9&_uhb=1#ht_4557wt_1141)


Hope that helps.

Regards
Ray

[Humphrey9999]

Hi Aaron,

You can get all you need on ebay pretty cheap, first you need a power supply, then a step generator and finally a motor driver.

Not sure what power you need, but if 12v is sufficient then there are plenty of options, like an old PC power supply for example, will provide the 12V for the motor, and 5v for the generator logic

The step generator provides the pulses needed for the motor driver most have forward/reverse switching and speed control. here's one for $11.43 incl free shipping

Stepper motor Pulse Signal Generator module/Speed Regulator /driver controller | eBay (http://www.ebay.com.au/itm/Stepper-motor-Pulse-Signal-Generator-module-Speed-Regulator-driver-controller-/181072386381?pt=LH_DefaultDomain_0&hash=item2a28c1594d&_uhb=1#ht_2173wt_1165)

Now you need a motor driver... these are as cheap as chips on ebay... this one is $9.99

L298N Dual H Bridge DC stepper Motor Driver Controller module Board for robot | eBay (http://www.ebay.com.au/itm/L298N-Dual-H-Bridge-DC-stepper-Motor-Driver-Controller-module-Board-for-robot-/300828412153?pt=AU_B_I_Electrical_Test_Equipment&hash=item460ac548f9&_uhb=1#ht_4557wt_1141)


Hope that helps.

Regards
Ray

Best answer so far.
(Gotta wait a week, though - This seller is currently away until 17 February 2013. If you make a purchase, there may be a delay in processing your order.)

[azzrock]

hi malibu. humphrey,, sim,and of course rayg.
i should of known it wouldn't be simple.

[SAISAY]

Jumping in here
What does the number of wires mean?

[Humphrey9999]

Jumping in here
What does the number of wires mean?

There are 2 basic types of stepper - unipolar and bipolar. Both have two coils, but a unipolar motor has 6 wires, comprising two centre-tapped windings whereas a bipolar motor has 4 wires, two windings without centre-taps.

With a unipolar motor, the centre-tap is connected to one power rail and one or the other end is then connected to the other rail in sequence to step the motor.

In the case of a bipolar motor, with no centre tap, the driver must reverse the polarity of the entire coil to step - a much more complicated driver needing 2 H-bridges per coil.