I recall this same problem on an antique Andover system about 15 years ago. Don't know the words you are using but the electronic to pneumatic pulsed transducer needs the signal sent to it every few seconds. about 10 to 30 as I recall, otherwise it just 'forgets' the signal and goes wide open or shut. So your software must repeat your output signal before the transducer forgets the input signal. Gotta read the little papers that come with the transducers. Good Luck,
Hehehe, the little papers just said how to change settings, not what settings to use. That's the issue. I had no clue what 25.5 sec meant in the grand scheme of the operation of the actuator. I have a better understanding of it now and think that 25.5 would be the same as 10 it would just take longer for the valve to achieve desired position.
Stupid lil papers should be more intuitive and tell ME exactly what do all the time.
He who asks a question is a fool for five minutes. He who does not ask any questions is a fool forever.