Reset Input

Edge-triggered input used for the following purposes:

  • Manually resetting function block error states when the cause of the error is no longer present.

  • Manually resetting of the start-up inhibit which is active by default after starting up the SLC and after activating the function block.

  • Manually resetting of a restart inhibit which is active by default following an STO or SS1 function request to help prevent the unintended restart of the axis.

NOTE:

The Reset input supports manual resetting of a start-up/restart inhibit by the operator (see EN ISO 13849-1). Additional measures, for example, an additional function stop, can be taken to reduce the risk of an unintended start-up.

NOTE:

Resetting does not occur with a falling edge (TRUE > FALSE), as specified by standard EN ISO 13849-1, but with a rising edge (FALSE > TRUE).

Data type: BOOL

Initial value: FALSE

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

 WARNING

UNINTENDED EQUIPMENT OPERATION

Make certain that the Reset input is not connected to any other device than a suitable manual reset device.

Failure to follow these instructions can result in death, serious injury, or equipment damage.

Value

Description

FALSE

Removal of an active start-up/restart inhibit is not requested.

Edge FALSE > TRUE

Removal of an active start-up/restart inhibit is requested.

The function block performs internal edge monitoring for the Reset input. A reset is only executed on a rising edge. A further static TRUE signal after a rising edge has no effect.

Refer to the hazard message below this table.

 WARNING

UNINTENDED START-UP

  • Include in your risk analysis the impact of removing the start-up/restart inhibit by means of a rising 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 removing the start-up/restart inhibit.

  • Do not enter the zone of operation when removing the start-up/restart inhibit.

  • Ensure that no other persons can access the zone of operation when removing the start-up/restart inhibit.

  • Use appropriate safety interlocks where personnel and/or equipment hazards exist.

Failure to follow these instructions can result in death, serious injury, or equipment damage.

NOTE:

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