Post by thread:[PIC]Driving stepper motors

What's the best way to drive a couple of stepper motors with a PIC? Specifically, these stepper motors: http://www.mpja.com/prodinfo.asp?number=17748+MS The only two ways I can think of doing this are: 1) Transistors 2) Stepper motor driver IC Which do you think would work better? I'm having trouble finding a 2A stepper motor driver :-)

On Tue, Jun 02, 2009 at 12:52:48PM -0500, Nathan House wrote: > What's the best way to drive a couple of stepper motors with a PIC? > Which do you think would work better? I'm having trouble finding a 2A > stepper motor driver :-) Check out Allegro Micro: http://www.allegromicro.com/en/Products/Categories/ICs/motor.asp -Chris -- | Christopher Cole, Cole Design and Development, LLC spam_OUTcoleTakeThisOuTcoledd.com | | Embedded Software Development and Electronic Design http://coledd.com | | Stow, Ohio, USA 800-518-2154 |

Actually, ST has some identical devices at a lower price and better availability (Mouser & Digikey). --Bob A On Tue, Jun 2, 2009 at 10:47 AM, Christopher Cole <.....coleKILLspam@spam@coledd.com> wrote: {Quote hidden}> On Tue, Jun 02, 2009 at 12:52:48PM -0500, Nathan House wrote: >> What's the best way to drive a couple of stepper motors with a PIC? >> Which do you think would work better? I'm having trouble finding a 2A >> stepper motor driver :-) > > Check out Allegro Micro: > http://www.allegromicro.com/en/Products/Categories/ICs/motor.asp > > -Chris > > -- > | Christopher Cole, Cole Design and Development, LLC coleKILLspamcoledd.com | > | Embedded Software Development and Electronic Design http://coledd.com | > | Stow, Ohio, USA 800-518-2154 | >

>Check out Allegro Micro: >http://www.allegromicro.com/en/Products/Categories/ICs/motor.asp Thanks for the link! Just after a quick glance, it looks like the lowest output voltage on any of these drivers is 8V. Since the motor that I will be buying (the one that I linked to) says it's 3.6V, do you think that will be a problem?

On Tue, Jun 02, 2009 at 01:11:51PM -0500, Nathan House wrote: > >Check out Allegro Micro: > >www.allegromicro.com/en/Products/Categories/ICs/motor.asp > > Thanks for the link! Just after a quick glance, it looks like the lowest > output voltage on any of these drivers is 8V. Since the motor that I will be > buying (the one that I linked to) says it's 3.6V, do you think that will be > a problem? Not a problem, you strap the driver chip for the required drive current based upon your motor, with consideration for the desired speed and torque that you need. The steppers are driven in current-control mode. Take care, -Chris -- | Christopher Cole, Cole Design and Development, LLC .....coleKILLspam.....coledd.com | | Embedded Software Development and Electronic Design http://coledd.com | | Stow, Ohio, USA 800-518-2154 |

> 1) Transistors > 2) Stepper motor driver IC The L297 / L298 pair are commonly used together L297 logic interface http://www.st.com/stonline/products/literature/ds/1334/l297.htm L298 power driver http://www.st.com/stonline/books/ascii/docs/1773.htm Microchip have an application note for a PIC functioning as a logic interface like the L297, which is the more expensive of the above pair. It wouldn't be hard to write your own The L298 is very good value for money and it's hardly worth trying to emulate it with discrete parts Using a motor rated lower than the supply is not a problem. One of the functions of a driver is to measure the current through the coils and cut the drive if it exceeds a defined value. The L298 does this with a sense resistor and comparator. Another technique is to use a power resistor in series with each coil A well-regarded stepper tutorial which explains all the basics http://www.cs.uiowa.edu/~jones/step/

I also used the L297/L298 pair to drive a stepper with good results. 2009/6/3 Jinx <EraseMEjoecolquittspam_OUTTakeThisOuTclear.net.nz> {Quote hidden}> > 1) Transistors > > 2) Stepper motor driver IC > > The L297 / L298 pair are commonly used together > > L297 logic interface > > http://www.st.com/stonline/products/literature/ds/1334/l297.htm > > L298 power driver > > http://www.st.com/stonline/books/ascii/docs/1773.htm > > Microchip have an application note for a PIC functioning as a logic > interface like the L297, which is the more expensive of the above > pair. It wouldn't be hard to write your own > > The L298 is very good value for money and it's hardly worth trying > to emulate it with discrete parts > > Using a motor rated lower than the supply is not a problem. One of > the functions of a driver is to measure the current through the coils and > cut the drive if it exceeds a defined value. The L298 does this with a > sense resistor and comparator. Another technique is to use a power > resistor in series with each coil > > A well-regarded stepper tutorial which explains all the basics > > http://www.cs.uiowa.edu/~jones/step/<http://www.cs.uiowa.edu/%7Ejones/step/> > -

On Tue, 2 Jun 2009 12:52:48 -0500, Nathan House wrote: > What's the best way to drive a couple of stepper motors with a PIC? > Specifically, these stepper motors: > http://www.mpja.com/prodinfo.asp?number=17748+MS > > The only two ways I can think of doing this are: > > 1) Transistors > 2) Stepper motor driver IC > > Which do you think would work better? I'm having trouble finding a 2A > stepper motor driver :-) Morning Nathan. I bought a bunch of L6207s for my stepper project; they do up to 2.5A per winding IIRC (check the datasheet - it also varies between the type of package that they come in). They also do the chopping and have an overcurrent / overheat flag. Seemed to work alright with a PIC16F685 (needed pulse steering for microstepping) and also the PIC16F684 (I couldn't get microstepping working with that, but fullstepping was fine). I haven't tried them with a decent power supply yet though (ie. > 12V @ 1200mA) - I need to build that. Of course you could do it yourself with discrete power MOSFETs; the dead time on the PWM module comes in handy for this. I also liked the look of the LMD18200 or LMD18201, but they were very expensive (and only had one channel - the L6207 has two). Then I found a very cheap supplier on e-Bay, a few days after I'd got the L6207s - cannot remember their name though, but just do a search as that's how I found them. I think their price was for two LMD18200s (*very* cheap when you look at other suppliers' costs for single units). Hope this helps. Regards, Pete Restall

On Tue, 2 Jun 2009 13:11:51 -0500, Nathan House wrote: > Thanks for the link! Just after a quick glance, it looks like the lowest > output voltage on any of these drivers is 8V. Since the motor that I will be > buying (the one that I linked to) says it's 3.6V, do you think that will be > a problem? That tends to be typical; steppers are usually driven from higher voltages for higher torque, but the current in the windings is limited. Check out this link, which isn't a bad starting resource on steppers and how to drive them: http://www.cs.uiowa.edu/~jones/step/index.html Take a look around http://www.cnczone.com too - there's lots of posts in there about the electronics side of things (plus some general 'rules of thumb' on determining safe maximum voltages for steppers, which isn't generally specified in manufacturers' datasheets). You'll have to dig for that sort of info though. Regards, Pete Restall

Hi Nathan, There one important question/information: it is an hobby project? This can drive to very different responses! Nathan House wrote: > What's the best way to drive a couple of stepper motors with a PIC? > Specifically, these stepper motors: > www.mpja.com/prodinfo.asp?number=17748+MS > Look at the datasheet: the data in the web page are different! > The only two ways I can think of doing this are: > > 1) Transistors > 2) Stepper motor driver IC > > Which do you think would work better? I'm having trouble finding a 2A > stepper motor driver :-) > You can use some ULN2003 or similar.

>There one important question/information: it is an hobby project? >This can drive to very different responses! Yes, this is a hobby project. Sorry for not clarifying that. One requirement for my motor controller is that it needs to be through-hole, like a PDIP. The L298HN comes in a MULTIWATT 15L IN LINE package, which I've never heard of. Does anyone know if this package would work for me, or should I not continue looking at this driver? The ULN2003 looks as if it only provides .5A (unless you can somehow combine channels?), which would not be enough for the motors I'm planning on using.

> The L298HN comes in a MULTIWATT 15L IN LINE package, > which I've never heard of. Does anyone know if this package would > work for me, or should I not continue looking at this driver? Multiwatt is a common package for power devices like audio amps. They have heavier pins than ICs and mount vertically with the heatsink able to be bolted to a panel, eg like you'd find in many car stereos There are two rows of pins. The front row of 8 is on 0.1" spacing, the second row of 7, also 0.1" spacing, is 0.2" behind the first, with back pins between the front. It's quite similar to a DB15 (eg PC game port) except the 0.2" between rows. A DB15 is 0.1" The pins of either row are long enough to bend sideways to fit a 0.1" grid, like a narrow DIP IC, so would work with Vero-type board. Trust me, got one right here