Functional description

Dieses Thema enthält die folgenden Abschnitte:

The SF_PSE function block monitors the switching states of pressure-sensitive protective equipment (e.g., a safety mat, safety panel, safety edge or switching strip) and executes stop category 0 at its output. S_StartReset and S_AutoReset can be used to specify a start-up inhibit and a restart inhibit.

Hinweis
This documentation refers to the pressure-sensitive protective equipment as PSE for short.

Triggering the PSE

When the connected PSE triggers, the function block ensures that the enable signal at the S_PSE_Out output switches to SAFEFALSE. The process being controlled is stopped.

Start-up inhibit (S_StartReset)

S_StartReset is used to specify the start-up inhibit after activating the function block and/or starting the Sicherheitssteuerung.

S_StartReset = SAFEFALSE After the Sicherheitssteuerung has been started up and/or the function block has been activated at input Activate, the start-up inhibit is active. The start-up inhibit is only removed if there is a positive signal edge at the Reset input.
Refer to the warning below this table.

S_StartReset = SAFETRUE After the Sicherheitssteuerung has been started up and/or the function block has been activated at input Activate, no start-up inhibit is active.
Refer to the section "Warning when using ...".

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).

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.

Restart inhibit (S_AutoReset)

S_AutoReset is used to specify the restart inhibit that is active when the connected PSE that was previously triggered is no longer triggered (as the safety mat, for example, is cleared again).

S_AutoReset = SAFEFALSE Once the PSE that was previously triggered is no longer triggered, the restart inhibit becomes active. The restart inhibit is only removed if there is a positive signal edge at the Reset input.
After the restart inhibit has been removed, the status at the S_PSE_Out output can switch from SAFEFALSE to SAFETRUE.
Refer to the warning below this table.

S_AutoReset = SAFETRUE The restart inhibit is not specified. As soon as the PSE that was previously triggered is no longer triggered, and the value SAFETRUE is present at the S_PSE_In input again, the S_PSE_Out output automatically switches to SAFETRUE.
Refer to the section "Warning when using ...".

Removing the restart 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).

WARNUNG

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.

Warning when using S_AutoReset = SAFETRUE and/or S_StartReset = SAFETRUE

The start-up inhibit and/or restart inhibit must only be deactivated if it is certain that starting up/restarting the machine/system will not lead to a hazardous situation or that a suitable start-up/restart 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) and/or restart inhibit (S_AutoReset = SAFETRUE) on your machine or process prior to implementation.

Observe the regulations given by relevant sector standards regarding the start-up/restart inhibit.

Verify that a suitable start-up inhibit is in place at another location or using other means.

S_StartReset = SAFEFALSE	After the Sicherheitssteuerung has been started up and/or the function block has been activated at input Activate, the start-up inhibit is active. The start-up inhibit is only removed if there is a positive signal edge at the Reset input. Refer to the warning below this table.
S_StartReset = SAFETRUE	After the Sicherheitssteuerung has been started up and/or the function block has been activated at input Activate, no start-up inhibit is active. Refer to the section "Warning when using ...".