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Reset input

Edge-triggered input used for the following purposes:

Data type: BOOL
Initial value: FALSE

The Reset input supports manual resetting of an active start-up or restart inhibit by the operator (see EN ISO 13849-1).

Hinweis
Resetting does not occur with a negative (falling) edge, as specified by standard EN ISO 13849-1, but with a positive (rising) edge.
To implement the reset with a falling edge (with regard to the mandatory acceptance procedure), use the safety-related function block SF_Reset.

Additional measures, e.g., an additional function stop, can be taken to reduce the risk of an unintended start-up.

Connection: With the signal of a reset button connected to the Sicherheitssteuerung (value TRUE or FALSE). Constant TRUE or FALSE values are not permitted.

ValueDescription
FALSEError resetting and removal of an active start-up inhibit are not requested.
Edge FALSE > TRUEError resetting and removal of an active start-up inhibit are requested.
The function block performs internal edge monitoring for the Reset input. A reset is only executed on a positive signal edge. A further static TRUE signal after a positive signal edge has no effect.

Resetting the function block by means of a positive signal edge at the Reset input can cause the S_GuardOut output to switch to SAFETRUE immediately (depending on the status of the other inputs).

WARNUNG
Unintended start-up
  • Include in your risk analysis the impact of the reset by means of a positive signal edge at the Reset input.
  • Make certain that appropriate procedures and measures (according to applicable sector standards) have been established to help avoid hazardous situations when resetting.
  • Do not enter the zone of operation when resetting.
  • Ensure that no other persons can access the zone of operation when resetting.
  • Use appropriate safety interlocks where personnel and/or equipment hazards exist.

Hinweis
If the function block is expecting a positive edge for resetting (inhibit is active or an error state applies), a static TRUE signal at Reset will be regarded as an error. In such cases, switch Reset to FALSE to exit the error state.

If neither a start-up inhibit nor a restart inhibit is specified (S_StartReset = SAFETRUE and S_AutoReset = SAFETRUE), it is not necessary to connect a manual reset.

WARNUNG
Unintended start-up
  • Be sure that your risk analysis includes an evaluation if both start-up inhibit and restart inhibit are deactivated (S_StartReset = SAFETRUE and S_AutoReset = SAFETRUE).
  • Use appropriate safety interlocks where personnel and/or equipment hazards exist.