CVS 7970 - Instructional Schematics; Pressure Sensing Low - Decreasing (PSL) Schematic

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Instructional Schematic: Pressure Sensing Low – Decreasing (PSL)
Normally Closed – Loss of Instrument (output) pressure, when sensed inlet pressure decreases below
the low pressure setting.
Reducing Pressure
Inlet Pressure Absent
Unactuated - Monitored process control pressure has
DECREASED below the Low Pressure Setting, or is absent.
Inlet Pressure Applied
Gaining Pressure
Actuated - Monitored process control pressure has
INCREASED above the Low Pressure Setting. Normal
operation.