S_SafetyActive input

State-controlled input for the feedback signal, which confirms that the selected operating mode (limitation of the speed or range of motion) is active.

Data type: SAFEBOOL
Initial value: SAFEFALSE

Connection: Connect this input to an evaluation unit (e.g., speed monitor) connected to the Sicherheitssteuerung, either directly or via other safety-related functions/function blocks. A constant SAFEFALSE value is not permitted. A constant SAFETRUE value is only permitted by taking into account the circumstances described in the following note.

Hinweis
Specify the requirements and/or measures to be implemented in the risk analysis you perform. If this risk analysis determines that the operating mode can be implemented safely in your application without any confirmation, you can connect the S_SafetyActive input to a constant SAFETRUE value.

If the function block is activated (input Activate = TRUE), the possible values at this input lead to the following function block behavior:

Value Description

SAFETRUE Confirmation that the operating mode is active is present.
The function block can switch the S_EnableSwitchOut output to SAFETRUE if the relevant conditions are met.
Refer to the warning below this table.

SAFEFALSE No operating mode is active.
The function block switches its S_EnableSwitchOut output to the defined safe state (SAFEFALSE) and retains this state.

Value	Description
SAFETRUE	Confirmation that the operating mode is active is present. The function block can switch the S_EnableSwitchOut output to SAFETRUE if the relevant conditions are met. Refer to the warning below this table.
SAFEFALSE	No operating mode is active. The function block switches its S_EnableSwitchOut output to the defined safe state (SAFEFALSE) and retains this state.

If no restart inhibit has been specified for the function block, the SAFETRUE status at the S_SafetyActive input can cause the S_EnableSwitchOut output to immediately switch to SAFETRUE (depending on the other input signals).

WARNUNG

Unintended start-up

If no restart inhibit is specified:

Be sure that your risk analysis includes an evaluation for the state change at the S_EnableSwitchOut output after applying the SAFETRUE status to the S_SafetyActive input.

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

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

Setting the operating mode

You must set the appropriate operating mode outside of the SF_EnableSwitch function block.

Possible operating modes are:

Limitation of the speed of motion
Limitation of the kinetic energy
Limitation of the range of motion

Typically, you use a mode selector switch, which you evaluate with the help of the safety-related SF_ModeSelector function block, to set the operating mode.

Single-channel or two-channel connection of the feedback signal?

Irrespective of whether there is a single-channel or two-channel feedback signal connected to the Sicherheitssteuerung, the S_SafetyActive input is only connected to one signal.

When using a two-channel feedback signal, it must be evaluated or monitored as follows:

Either with a suitable, upstream safety-related function block, e.g., SF_Equivalent.
Or the evaluation of equivalence or antivalence must be performed in the safety-related input device (see also section application example).