Implementation of safety requirements from applicable standards

The safety-related function block has been developed according to the safety requirements (from applicable standards) listed in this section. All other requirements from these standards must be observed when implementing the safety-related function.

This section describes either how the function block meets the requirements of the standards or what measures need to be taken to meet the requirements of the standards.

Standards Context/Requirement Implementation

EN 61496-1 Muting Appendix Protecting the zone of operation (muting is not active):
If the safety-related function block does not detect an active muting operation at its inputs, a SAFEFALSE signal at the S_AOPD_In input (light grid) results in the defined safe state SAFEFALSE of the S_AOPD_Out enable output.
Activating the muting operation:
For a material flow direction from left to right: The muting operation is activated when the muting sensors located before the safety-related equipment switch from SAFEFALSE to SAFETRUE one after the other (i.e., inputs S_MutingSwitch11 and S_MutingSwitch12).
For a material flow direction from right to left: The muting operation is activated when the muting sensors located before the safety-related equipment switch from SAFEFALSE to SAFETRUE one after the other (i.e., inputs S_MutingSwitch22 and S_MutingSwitch21).
Active muting operation:
When the muting operation is active, a SAFEFALSE signal at input S_AOPD_In does not result in the defined safe state SAFEFALSE of the S_AOPD_Out output.
The activated muting operation must be completed within the time specified at MaxMutingTime. If it is not completed within this time, the S_AOPD_Out output is switched to the defined safe state SAFEFALSE.
Completing the muting operation:
For a material flow direction from left to right: The muting operation is deactivated when the first muting sensor located behind the safety-related equipment (at input S_MutingSwitch21) switches back from SAFETRUE to SAFEFALSE, i.e., an object is no longer detected in the detection area. A SAFEFALSE signal at input S_AOPD_In then switches the S_AOPD_Out output to SAFEFALSE.
For a material flow direction from right to left: The muting operation is deactivated when the first muting sensor located behind the safety-related equipment (at input S_MutingSwitch12) switches back from SAFETRUE to SAFEFALSE, i.e., an object is no longer detected in the detection area. A SAFEFALSE signal at input S_AOPD_In then switches the S_AOPD_Out output to SAFEFALSE.
Invalid muting sequences:
States at inputs S_MutingSwitch11, S_MutingSwitch12, S_MutingSwitch21 and S_MutingSwitch22 which are invalid for the muting operation will cause the S_AOPD_Out output to be switched to the defined safe state SAFEFALSE. Refer to chapter "Functional description", section "Muting errors" for more information.
Start-up inhibits:
Once the function block has been activated, it can execute a start-up inhibit as an option (depending on the setting at S_StartReset). After the function block has detected an invalid muting sequence or another error, that error must be removed and then confirmed by means of a manual reset. This procedure prevents an automatic restart from occurring following error removal.
Status of the muting operation:
The status of the muting operation is output at the S_MutingActive output of the function block.

EN IEC 62046:2008 Override depending on muting Access to the zone of operation in the event of muting errors:
A manually operating and muting-dependent override function can be required to clear the zone of operation from objects which cause blockings. However, this function may only be used when the danger potential is calculable, see ISO 12100-2, 4.11.9.

Activation:
Override may only be activated when at least one muting sensor is active and/or the safety-related equipment is deactivated (input S_AOPD_In = SAFEFALSE). It must not be possible to activate override in the event of faults (other dangerous error states). In addition, it may only enable actions to clear blockings and drive the object outside the zone of operation.

Execution:
The activation must be initiated by a control device with return spring, a key switch or similar. The trigger must be activated (pressed) for the duration of the override operation and automatically return into its starting position when released. It must be placed in a position with an unlimited view of the zone of operation during the activation and next to an emergency-stop button.

Automatic exit:
Override must be exited automatically,

when all muting sensors are deactivated and also the light grid detects no object S_AOPD_In = SAFETRUE

after the previously defined time period (MaxOverrideTime) has elapsed

in the event of an (other) error.

EN ISO 13849-1 Manual reset device The Reset input supports the function of a manual reset device.

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.

EN ISO 12100-2 Start-up after failure of supply voltage/spontaneous restart You can select whether the function block will support automatic start-up of the function block or a start-up inhibit

after the Sicherheitssteuerung has been started up and

after the function block has been activated by applying a TRUE signal to the Activate input.

The function block provides a start-up inhibit

after an invalid muting sequence,

after an error message for the function block and

when the safety-related function is no longer requested.

If the Activate input does not indicate the status of the safety-related devices, you must implement this function by other means.
You are responsible for planning and implementing the start-up behavior according to your risk analysis.
To prevent an unintended start-up, you may need to perform an additional function start once the safety-related function has been reset. This will depend on the results of the risk analysis, the signal path of the reset signal, and/or the setting at S_StartReset.

EN ISO 13849-1 Category B to 4 Single-channel or two-channel connection must be implemented depending on the category.

Hinweis
Cross-circuit monitoring is not performed by the function block. It is your responsibility to perform this monitoring function outside of this function block in the safety-related control system, by connecting an SF_Equivalent function block upstream for the purpose of evaluating signals, for example.

EN 60204 Stop functions The function block (S_AOPD_Out enable signal) executes stop category 0.