BECKHOFF TwinSAFE - Manual (Page 45)

Circuit examples
Application Guide TwinSAFE 43
2.7 ESTOP function variant 7 (Category 4, PL e)
The emergency stop button with two break contacts, the restart and the feedback loop are connected to
safe channels of an EL1904 input terminal. The testing of the emergency stop button is deactivated on
both channels. The sensor test is activated for the restart button and the feedback loop. The two
emergency stop signals are tested for discrepancy. 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.
2.7.1 Parameters of the safe input and output terminals
1. EL1904
Parameter Value
Sensor test channel 1 active Yes
Sensor test channel 2 active not used
Sensor test channel 3 active No
Sensor test channel 4 active No
Logic channel 1 and 2 Single Logic
Logic channel 3 and 4 Single Logic
2. EL1904
Parameter Value
Sensor test channel 1 active not used
Sensor test channel 2 active not used
Sensor test channel 3 active Yes
Sensor test channel 4 active not used
Logic channel 1 and 2 Single Logic
Logic channel 3 and 4 Single Logic