Automatic valve section
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If I/P is the conversion of voltage to air pressure, then what does S/P mean? A conventional control valve uses a voltage signal from the controller; the voltage in the positioner is converted into air pressure to control the operation of the valve. The cut-off valve is used to release air from the valve, thereby enabling rapid shutdown. Valves that are shared by both SIS and DCS are those that can have their opening degree controlled by the DCS as well as be used for emergency shutdown by the SIS. What is the principle of operation? It seems to be controlled by power or air pressure; then why did the teacher say it’s a solenoid valve? I work in the manufacturing field, and I really can’t understand this automatic control system. I hope the experts here can explain it to me
This post was last edited by ylb913 on 2018-7-8 at 12:01. An interlock for control valves involves adding a two-position three-way solenoid valve to the output pipeline of the control valve’s positioner; under normal conditions, air is supplied to the control valve, but during interlock operation, the supply of air to the control valve is cut off, and at the same time, the instrument air behind the solenoid valve is released.