Functional Safety KFD2-RSH-1.2E.L*(-Y1)
Operation
2
01
9-
12
21
5.3.2
Application with Fault Indication Output in the Signal Loop
of the Dual Pole Switching
Some process control systems are not working with test pulses or with specific test pulses
that do not recognize the impedance change of the device output signaling a line fault.
Where the output of the process control system can detect an open circuit in the signal loop,
the fault indication output of the device may be put in series to the input. See figure.
Figure 5.2 Application with fault indication output in the signal loop of the dual pole switching
If the fault indication output is open, the output relay contacts cannot be enabled.
But as the fault is detected by the process control system a suitable reaction can be planned.
The user must ensure that a suitable reaction on this detected fault is implemented.
For this application, the characteristic safety values are the same. The characteristic safety
values can be found in Table 3.1.
KFD2-RSH-1.2E.L2
KFD2-RSH-1.2E.L3
7+
6
3
2-
ETS
8-
10
11
Zone 2
24 V DC
14+
15-
Power Rail
24 V DC
Fault
5+
V
Warning!
Possible failure of the safety function
If a fault is detected, all output relay contacts remain open.
Take suitable measures in case the diagnosis is triggered. Take suitable measures to sustain
the safety function via the process control system.