A parameter issue regarding pneumatic switch butterfly valves
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In the specifications for pneumatic butterfly valves, there is a field titled \"Valve operation mode\"; in this field, one should enter either \"Operate while powered on\" (EO) or \"Close while powered on\" (EC). How should this be chosen, and what factors determine it? I would appreciate guidance from those with more experience
It is generally denoted as FC or FO: FC stands for fault closed, while FO stands for fault open; the choice is determined based on process and safety requirements
Well, fault on and fault off are two different concepts from operating with power and operating without power
The operation of pneumatic valves with the valve open while energized (EO) or closed while energized (EC) is typically a functional requirement of valve positioners or electrical converters that control solenoid valves. In most cases, after determining whether the pneumatic valve should operate in fail-closed (FC) or fail-open (FO) mode based on process requirements, the control signal setting becomes \"shut off gas in case of failure\". In other words: in the event of a power loss, the pneumatic signal output by the valve positioner or electrical converter, as well as the control solenoid, results in a gas-shut-off state. At this point, the overall state of the valve (together with the electro-pneumatic conversion device) is either open under voltage (EO) or closed under voltage (EC). In fact, the specific selection is similar to that of the interlock solenoid valve on the control valve; that is, there is no air signal either when there is no electrical signal. .