BECKHOFF TwinSAFE - Manual (Page 9)

Circuit examples
Application Guide TwinSAFE 7
2 Circuit examples
2.1 ESTOP function variant 1 (Category 3, PL d)
The emergency stop button is connected via two break contacts to an EL1904 safe input terminal. The
testing and monitoring of the discrepancy of the two signals are activated. The restart and the feedback
signal are wired to standard terminals and are transferred to TwinSAFE via 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.
2.1.1 Parameters of the safe input and output terminals
EL1904
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