BECKHOFF TwinSAFE - Manual (Page 51)

Circuit examples
Application Guide TwinSAFE 49
2.8 Protective door function variant 1 (Category 3, PL d)
The protective door uses a combination of break and make contacts on the safe inputs of an EL1904. The
testing of the inputs is active and the signals are tested for discrepancy (200 ms). The feedback loop is
read via a standard input and transferred to TwinSAFE via the standard PLC. The contactors K1 and K2
are connected in parallel to the safe output. Current measurement and testing of the output are active for
this circuit.
2.8.1 Parameters of the safe input and output terminals
EL1904 (applies to all EL1904 used)
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
EL2904
Parameter Value
Current measurement active Yes
Output test pulses active Yes