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S_StartStopOverride input

State-controlled input for the request/removal of the override function by the operator.

Connection: Connect this input to a corresponding control device, e.g., a key switch or push button with temporary effect. Constant TRUE or FALSE values are not permitted.

Hinweis
The control device (e.g., a key switch) must be activated for the duration of the override operation and return into its starting position when released.

Hinweis
You have to place the control device in a position where the zone of operation can be watched!

The status at the S_StartStopOverride input has only an impact if an override operation is possible (output OverridePossible = TRUE).

When the function block is activated (input Activate = TRUE) and output OverridePossible = TRUE,  i.e.,

then the possible values at this input lead to the following function block behavior:

ValueDescription
SAFEFALSEThe override function is not requested.

If the override operation is interrupted by releasing the control device (S_StartStopOverride = SAFEFALSE), the override timer (MaxOverrideTime input) continues to run.
SAFETRUEThe override function is requested.

If the requirements for the override function are given (OverridePossible = TRUE):
  • the safety shutdown is temporarily deactivated, i.e., the S_AOPD_Out output switches to SAFETRUE,
  • the override timer (MaxOverrideTime) starts,
  • the OverrideActive output switches to TRUE.

Hinweis
If the override operation is interrupted, although the muting error still exists, the S_AOPD_Out output switches to SAFEFALSE and the Error output to TRUE.

WARNUNG
Non-conformance to safety function requirements
  • Be sure that your risk analysis includes an evaluation of a manual override operation (S_StartStopOverride = SAFETRUE).
  • Observe the regulations given by relevant sector standards regarding the override operation.
  • Make certain that appropriate procedures and measures (according to applicable sector standards) have been established to help avoid hazardous situations when activating the override operation.