S_AutoReset input

This input is used to specify the restart inhibit after the SAFETRUE signal returns at the S_EStopIn input (in other words, once the safety-related function is no longer requested).

When a restart inhibit is active, all safety-related outputs of the function block are in the defined safe state. This ensures that a machine/system cannot be restarted inadvertently. If a restart inhibit has been specified, a reset signal is required to remove the inhibit and enable the machine/system to function.

Data type: SAFEBOOL

Initial value: SAFEFALSE

Connection: Connect this input to a variable or constant.

If Activate = TRUE, the possible values at S_AutoReset lead to the following function block behavior:

Value

Description

SAFETRUE

No restart inhibit for the function block when the safety-related function is no longer requested.

If no restart inhibit has been specified for the function block, the SAFETRUE status at the S_EStopIn input can cause the S_EStopOut output to immediately switch to SAFETRUE.1

SAFEFALSE

Active restart inhibit for the function block after the SAFETRUE signal returns at the S_EStopIn input (in other words, once the safety-related function is no longer requested).

The restart inhibit must be manually removed by means of a reset signal (positive signal edge) at the Reset input.2

1

If no restart inhibit is specified, observe the following:

 WARNING

UNINTENDED START-UP

  • Be sure that your risk analysis includes an evaluation for the state change at the S_EStopOut output after applying SAFETRUE to the S_EStopIn input.

  • Make certain that appropriate procedures and measures (according to applicable sector standards) have been taken to help avoid hazardous situations when applying SAFETRUE to the S_EStopIn input.

  • 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.

2

After the restart inhibit has been removed, the status at the S_EStopOut output can switch from SAFEFALSE to SAFETRUE immediately if there is a valid signal combination at the other inputs.

 WARNING

UNINTENDED START-UP

  • Verify the impact of removing the restart inhibit 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 taken to help avoid hazardous situations when removing the restart inhibit.

  • Do not enter the zone of operation when removing the restart inhibit.

  • Ensure that no other persons can access the zone of operation when removing the 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.

 WARNING

NON-CONFORMANCE TO SAFETY FUNCTION REQUIREMENTS

Verify that a restart inhibit facility is implemented in your safety-related network if required for your specific safety-related function according to the relevant standards.

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

 WARNING

UNINTENDED START-UP

Validate the behavior of the function block and the safety-related network as a whole and thoroughly test the application.

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