I’m working on a digital servo from futaba s3156 where the servo horn position measurement is read. I tried reading the servo internal potentiometer to correlate the servo angle. Only the wiper line and gnd are extend from servo. At normal condition, the analog value read vary in a reasonable range. However, when there is load impose and real time reading of the analog value didn’t reflect the correct position angle. I’m not really understand the servo motor circuit to think of possible reason.
Maybe noise?
Try adding small cap, .1 to .1 uF.
Alan KM6VV
Are you connecting to the pot ground or the main servo ground? What is the voltage across the pot and does the voltage across the pot change when the load changes?
It is the ground of potentiometer that is connected. Haven’t measured the voltage using meter, but read as analog voltage from microcontroller. The normal voltage range is [0.797 1.329]V.