stepper motor current draw

The short answer is that I don't think it will damage the Make Controller.

How warm is pretty warm?  Generally, warm isn't a problem.  Hot is a problem, though these parts are rated for 85C, which is pretty hot, indeed.  So long as the environment (heat sinking, airflow, etc.) is sufficient to keep the die temperature within safe range and below the thermal shutdown limit, it should be ok.  These drivers do have thermal shutdown circuitry which will shut drivers off until the temperature returns to an acceptable range.  That feature is there to try to prevent destroying the drivers with too much heat.

in your programming, try setting the duty to 0 whenever you're not moving. Steppers use a lot of current to hold their position, but in some applications, this is not necessary. If you set the duty to 0, you'll eliminate this unnecessary current draw and thus keep things a lot cooler.

Yes.  Depending, as you say, on the application, of course.  For something like a wheeled robot on level ground, or something with a spring or gravity return to an inert/safe position, that is absolutely true.

For systems that still require holding the position of a mechanism (lest it roll downhill or otherwise move to an unwanted position), you can still reduce the power by setting the duty to something between 0 and maximum when you're just holding and not trying to change position.  That value will need some tweaking, as it depends on the mechanism and your motors.  I'm assuming that the motor/system does not have a clutch which performs the holding function without having to energize the motor coils.  Most do not.

Also, if hold power is really an issue, you might want to consider single-stepping in preference to half-stepping.  Half-stepping has its advantages, but it does, by definition, draw twice the power in certain positions.

Previously Aaron Tunell wrote:

><p>in your programming, try setting the duty to 0 whenever you're not moving. <p>
><blockquote>

Ah, of course! My application can certainly do with a lower duty cycle when the motors are stationary, though I do need stop in precise locations. In any case, this should cool things down. Thanks much Lou and Aaron. Scott