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SHUTDOWN Logic - HIGH OFF LOW ON
The ↑ OFF ↓ ON shutdown logic stops all processes except for the INDEPENDENT process when there is a transion of
the SOURCE value from above to at or below the LOW LEVEL shutdown seng and the processes can only be started
again once there is a transion from below to at or above the HIGH LEVEL shutdown seng (Image 3.4.17).
Time
LOW LEVEL
SHUTDOWN
INACTIVE
SHUTDOWN
ACTIVE
Events
SHUTDOWN CURRENT
VALUE
HIGH LEVEL
SHUTDOWN Logic - HIGH ON LOW OFF
The ↑ ON ↓ OFF shutdown logic stops all processes except for the INDEPENDENT process when there is a transion of
the SOURCE value from above to at or below the HIGH LEVEL shutdown seng and the processes
can only be started again once there is a transion from below to at or above the LOW LEVEL shutdown seng
(Image 3.4.18).
Time
LOW LEVEL
Events
SHUTDOWN CURRENT
VALUE
HIGH LEVEL
SHUTDOWN
SHUTDOWN
INACTIVE
SHUTDOWN
ACTIVE
Image 3.4.17 · SHUTDOWN logic - HIGH OFF LOW ON
Image 3.4.18 · SHUTDOWN logic - HIGH ON LOW OFF