Answer Posted / kuntal nayek
Yes we can use control valves without positioner.
But it will be risky as we would not able to know the
feedback that valve is working properly or not.
Normally position feedback is used to get the actual
position of the valves it is not used to control the valves.
To control a control valves we needed the process value that
usually called PV..that may be pressure, flow etc which we
could get from the transmitters or any other instruments.
According to PV controller generate corrected signal (ie.
Setpoint - Process value = error)in terms of 4-20mA.
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