BECKHOFF TwinSAFE - Manual (Page 97)

Circuit examples
Application Guide TwinSAFE 95
2.16 Muting (Category 4, PL e)
The light curtain has two OSSD outputs (Output-Signal-Switching-Device), which are wired to safe inputs
of an EL1904. The testing of the inputs is not active, since the OSSD outputs carry out their own test.
Furthermore, the signals are checked for discrepancy (200 ms). The feedback loop is read via a safe
input. The muting switches and the enable switch are also wired to safe inputs. Testing is active for these
inputs.
The contactors K1 and K2 are connected in parallel to a safe output. The muting lamp is also wired to a
safe output. Current measurement and testing of the output are active for this circuit.
2.16.1 Parameters of the safe input and output terminals
EL1904 (upper terminal on the drawing)
Parameter Value
Sensor test channel 1 active No
Sensor test channel 2 active No
Sensor test channel 3 active Yes
Sensor test channel 4 active Yes
Logic channel 1 and 2 OSSD asynchronous analysis
Logic channel 3 and 4 Single Logic
EL1904 (lower terminal on the drawing)
Parameter Value
Sensor test channel 1 active Yes
Sensor test channel 2 active Yes
Sensor test channel 3 active Yes
Sensor test channel 4 active Yes
Logic channel 1 and 2 Single Logic
Logic channel 3 and 4 Single Logic