Power HD DS120M + Micro Maestro USB: Setting end point

I have bought 2 Power HD High-Speed Digital Servo DS120M:
pololu.com/catalog/product/1350

Connected them to a micro maestro USB controller and was sad to found out they only support 90 degree range (45 both sides)

Without power I was able to move the servo little beyond 180 degrees (90 both sides) before hitting a ‘lock’. Is there a way to programmatically increase the end points of the servo’s? Sending longer and shorter pulses, something this controller is apparently uniquely qualified to do, will simply be ignored by the servo beyond the 90 degree range.

Or is the only way to increase the range by adding resistors to the pot, sacrificing accuracy in the process. If so, which resistances would I need?

Hello.

Just in case you haven’t tried these steps already, please see the FAQ entitled “How do I use my Maestro servo controller to get the maximum possible range of motion from my servo?” on our Maestro FAQ page:
pololu.com/catalog/product/1350/faqs

That FAQ covers how to increase the servo’s range by reconfiguring the Maestro. If the results from that are unsatisfactory, we can look into it and see if there are any other options for increasing the range.

–David

So yeah, tried that. had no effect

We are not aware of Power HD servos being limited by anything other than the end stops, so you should be able to get more than 90 degrees out of it without modifying the hardware.

For what it’s worth, I just tested a Power HD 1204 HP servo here and I was able to get a little bit more than 180 degree range by sending 576-2464 microsecond pulses. If I try to send a wider range of pulses, it strains itself. Could you tell me more about what pulse widths you have tried sending to your servo and how it behaves in different ranges?

–David