Positioners are used for modulating purposes in pneumatic actuation. They can be solely pneumatic providing a 3-15 PSIG or 6-30 PSIG input signal to throttle an actuator to its correct position. Alternately, pneumatic positioners can be equipped with an I/P allowing a PLC to provide a 4-20mA analog signal to the positioner where the I/P converts the milliamp signal to a pneumatic output of3-15 PSIG or 6-30 PSIG which is then fed to the actuator to drive it to the correct position. These electropneumatic positioners can be equipped with HART Smart communications.