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Topic: Stepper toggle possible? (Read 728 times) previous topic - next topic

nass

Hi, newbie question here.

I can't find any documentation to help me on a project, which at its core involves controlling 4 different microsteppers (with only one active at any time). Do I need 4 seperate shields, or is it possible to use buttons to make a toggle that'll only make one active at any time (ie just use 1 shield?).

Is this possible, stupid or...?

Can anyone point me to some URLs where this sort of question is under discussion?

Many thanks
Photography nut trying to make the flux capacitor of macro pho

Grumpy_Mike

Quote
Is this possible,

Yes
Quote
stupid or...

Possibly.
When a motor is no longer powered it not have any torque and so it is easy to move with an applied load. This is what would happen if you did this.

You would have to arrange a multi way switch or set of relays to switch the motors in and out of circuit
Not something many people want to do.

nass

Ok, thanks Mike. So the proper way of doing something like would be to have 4 stepper shields, with all of them on?

Thank you again
Photography nut trying to make the flux capacitor of macro pho

Grumpy_Mike


Ok, thanks Mike. So the proper way of doing something like would be to have 4 stepper shields, with all of them on?

Yes that is the proper way.

MarkT


Quote
Is this possible,



You would have to arrange a multi way switch or set of relays to switch the motors in and out of circuit
Not something many people want to do.


And of course physically breaking the connection to a powered up stepper winding is likely to
both burn out the stepper driver and weld your relay contacts shut - unless you power down the
driver before switching.

The first rule of stepper motors is don't disconnect a powered up motor...
[ I won't respond to messages, use the forum please ]

nass


The first rule of stepper motors is don't disconnect a powered up motor...


Mark thank you. Can you suggest any websites which would inform on such things, basic stepper rules, do's and don'ts, drivers and shields and whatnot. I have a very specific thing I want to build but having a devil of a time finding out info about it. Ie the shields I'm seeing arn't stackable so you're limited to 2 steppers... I'm after 4 (and a bunch of other bits). Where to find some reading material covering projects like this with many bits?

Thank you
Photography nut trying to make the flux capacitor of macro pho

wildbill

#6
Apr 26, 2013, 11:17 pm Last Edit: Apr 27, 2013, 02:24 pm by wildbill Reason: 1
Look at the reprap project - the prusa mendel has five steppers driven by an arduino - it does it using some little pololu boards, one per stepper that just need a couple of pins apiece. In the case of the reprap, those daughter boards are attached to the main RAMPS board, but there's no reason you couldn't control them directly from the arduino.

nass

Thank you very much wildbill, I'll do that.

Appreciate the pointers
Photography nut trying to make the flux capacitor of macro pho

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