BECKHOFF TwinSAFE - Manual (Page 103)

Circuit examples
Application Guide TwinSAFE 101
2.17 Feeding in a potential group (Category 4, PL e)
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 contactors K1 and
K2 are connected in parallel to the safe output. Current measurement and testing of the output are active
for this circuit.
The diagnostic information from the KL/EL9110 (24 V is present on the power contacts) is negated,
afterwards combined with the feedback signals from contactors K1 and K2 through a Bool AND
composition and the result is applied to the EDM input.
The supply to the power contacts (24V and also 0 V) of the potential group is switched off with the NO
contacts of contactors K1 and K2 . The 0 V potentials of the load employed (in this case K3 and K4) must
always be fed back to the potential group.
Notice
Safety consideration
The safety consideration ends at K1/K2. The EL/KL9110 and EL/KL2xxx terminals
used are not taken into account for the calculation.
B K 9 0 0 0
B
E C
K
H
O
F
F
KL9010
BECKHOFF
I/O RUN
I/O ERR
KL2xx2 BECKHOFF
KL2xx2
BECKHOFF KL9xxx BECKHOFF KL2xx2 BECKHOFF KL2xx2 BECKHOFF