-

S_StartReset input

This input is used to specify the start-up inhibit after the Sicherheitssteuerung has been started up or after the function block has been activated.

When a start-up 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 started up inadvertently. If a start-up inhibit is active, 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_StartReset lead to the following function block behavior:

ValueDescription
SAFETRUENo start-up inhibit for the function block after the Sicherheitssteuerung has been started up and after the function block has been activated.

If no start-up inhibit has been specified for the function block, the SAFETRUE status at the S_PSE_In input can cause the S_PSE_Out output to immediately switch to SAFETRUE.

Refer to the first warning below this table.
SAFEFALSEActive start-up inhibit after the Sicherheitssteuerung has been started up and after the function block has been activated.

The active start-up inhibit must be manually removed by means of a reset signal at the Reset input.

Removing the start-up inhibit by means of a positive signal edge at the Reset input can cause the S_PSE_Out output to switch to SAFETRUE immediately (depending on the status of the other inputs).

Refer to the second warning below the table.

WARNUNG
Unintended start-up

If no start-up inhibit is specified:
  • Be sure that your risk analysis includes an evaluation for the state change at the S_PSE_Out output after applying SAFETRUE to the S_PSE_In input.
  • Make certain that appropriate procedures and measures (according to applicable sector standards) have been established to help avoid hazardous situations when applying SAFETRUE to the S_PSE_In input.
  • Use appropriate safety interlocks where personnel and/or equipment hazards exist.

WARNUNG
Unintended start-up
  • Verify the impact of removing the start-up 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 start-up inhibit.
  • Do not enter the zone of operation when removing the start-up inhibit.
  • Ensure that no other persons can access the zone of operation when removing the start-up inhibit.
  • Use appropriate safety interlocks where personnel and/or equipment hazards exist.

The start-up inhibit must only be deactivated (S_StartReset = SAFETRUE) if it is certain that starting up the machine/system will not lead to a hazardous situation or that a suitable start-up inhibit is in place at another location or using other means.

WARNUNG
Non-conformance to safety function requirements
  • Verify the impact of a deactivated start-up inhibit (S_StartReset = SAFETRUE) on your machine or process prior to implementation.
  • Observe the regulations given by relevant sector standards regarding the start-up inhibit.
  • Verify that a suitable start-up inhibit is in place at another location or using other means if the start-up inhibit is deactivated by setting S_StartReset = SAFETRUE.

WARNUNG
Non-conformance to safety function requirements

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

WARNUNG
Unintended start-up

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