hi,
h2000's post #50 explains the problem, it appears to be a latency problem between a PC key press and the operation of a remote relay.
happytriger2000
The circuit I posted, just requires a single digital level change to go slowly from one pulse-width to the next
This statement suggests that you are commanding the head to move either forward/reverse at the maximum rate by closing a relay contact and then 'hopefully' pressing the relay Off command button when it reaches an observed position.??
Then when the head is at the desired position both fwd/rev relays will be switched Off
I am assuming that the pan/tilt head and the mass it is moving have a neutral balance when not powered.? so the head will hold it's position when not being driven.??
I would say that trying to control the pan/tilt position using that relay method will never give the required accuracy.
You have effectively an 'open' loop control electronic system, where the timing depends upon your key press response.
Eric
Carl's circuit sounds feasible, providing you can write program code.
The circuit I posted, just requires a single digital level change to go slowly from one pulse-width to the next.