Greetings. I've got a pair of the servo amps we're trying to use in a science olympiad robot (I'm the coach). The problem we're seeing is that we get either a relatively narrow range of motion, or practically no motion at all. It seems like the usable range of the feedback pot is very small.
I've tried both 5k and 10k pots. We're using an Arduino to send the control pulse. We started with the specified 1100-1500-1900 pulse timing as specified on the product page (and that has yielded best results), but the range of motion is amazingly small.
We're using standard Radio Shack pots, approx 300* mechanical range, with maybe 280* range of usable analog sweep. The pots are coupled directly to the shafts of two different joints. In one case, we're only able to get ~ 100 degrees of travel, and on the other, we get basically no usable movement, although if I position the shaft/pot just-so, I can get the servo to follow the joystick over a very narrow range.
I've tried varying the signal timing to outside the 1100-1500-1900 range, and the amp doesn't seem to like that at all. I'm looking at the Arduino serial monitor, so I can see that I'm getting good analog input, ranging from 0-1023, and that is being scaled to a 0-179 input to the standard Arduino servo library.
Any other ideas on what to try? If I can't get a good range of motion, I may have to sacrifice another analog input and monitor the feedback pot directly in the Arduino, and use the servo amp (or another h-bridge) to just drive the motor without direct feedback, but that defeats the whole point of purchasing the servo amp.
PS - a rapid response would be appreciated - this is making me look bad for my Student Olympians!!