Benchset Range - ATC-FO

Shutoff capability is directly proportional to the ability to "load" the actuator up to approximately 18 psig pressure level. If there is any instrument that will NOT load up to the 18 psig output pneumatic pressure, the shutoff capability will be reduced. Devices that can cause a problem by NOT loading up to the 18 psig level are:

- I/P Transducer with a 3-15 psig output range; the device may only load up to 16-17 psig level. for the above actuator, the shutoff capability is "reduced;" i.e. ((16.5-13)/5) x 600 = 420 psid.

- Some pneumatic controllers.

A device that DOES unload down to 0 psig is a POSITIONER.