How is the SSC 32 controller able to provide a resolution of 0.09 degrees (1 µs) when the servos themselves (on lynxmotion AL5D arm) have a resolution of 0.8 degrees (considering that a servo such as HS 755B has an extended range of 600-2400 µs pulse width and a dead bandwidth of 8 µs)
Also does the query command to the SSC32 return the actual position or the position stored in its registers?(considering that a servo has only a command pin to give it commands and no pin from the servo giving its actual position.)
The resolution specified for the SSC-32 board is related specifically to the output servo signal it can generate: it can generate a signal with pulses that range between 500µs to 2500µs with a precision of 1µs. Since most Hitec servos that are used in Lynxmotion kits have a range of 180 degrees for pulses that vary from 500 to 2500, that means the servo signal’s resolution is 180/2000 = 0.09 degrees.
You’re correct however that the servos themselves often don’t have that kind of precision, but since the max error for the servo’s actual position is the sum of a all the intermediate errors, it’s important to know the precision of each component. As you pointed out, the HS-755BB has a deadband of 8µs so although the SSC-32 can output a signal that changes by 1µs at a time, the servo won’t change until the change is 8µs or greater (0.72 degrees). If the precision of the SSC-32 were only 10µs, it would mean that you would need to change the signal by 10, 20, 30µs and wouldn’t be able to change your signal by 15µs.
As for the query command, you’re correct that it’s the position stored in its registers, which is also the value of the servo signal that the board is currently outputting. Unfortunately R/C signals don’t give any feedback signals, so if the servo is not holding the correct position or is idle, there’s no easy/practical way to know actual position.
