Reset input

Edge-triggered input used for the following purposes:

Resetting error messages when the cause of the error is no longer present.
Manual removal of the start-up inhibit/restart inhibit.

Hinweis
A start-up inhibit and restart inhibit which cannot be deactivated are specified in the safety-related SF_SafetyRequest function block by default.

Data type: BOOL
Initial value: FALSE

Hinweis
The Reset input supports manual resetting of a start-up 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.

Value Description

FALSE Error resetting and removal of an active start-up/restart inhibit are not requested.

Edge FALSE > TRUE Error resetting and removal of an active start-up/restart 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.

Value	Description
FALSE	Error resetting and removal of an active start-up/restart inhibit are not requested.
Edge FALSE > TRUE	Error resetting and removal of an active start-up/restart 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.

If the safety-related function is no longer requested (S_OpMode = SAFETRUE) before or during the rising signal edge at the Reset input (for resetting errors), this can signal to the system/machine that a request for the safety-related function is no longer present. This can lead to a risk, for example with the machine/system starting up immediately.

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 (start-up/restart 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.