Hirschmann RS20 series User Manual page 52

With a non-redundant supply of the supply voltage, the device reports the
loss of a supply voltage. You can prevent this message by changing the
configuration in the Management.
Signal contact for RS20/RS30/RS40

 The signal contact ("FAULT", for pin assignment of terminal block, see
figure 18) monitors the functioning of the device, thus enabling remote
diagnostics. You can specify the type of function monitoring in the
Management.
 You can also use the graphical user interface of the switch to switch
the signal contact manually and thus control external devices.
The potential-free signal contact (relay contact, closed circuit) reports
through a break in contact:
 The detected inoperability of at least one of the two voltage supplies
(voltage supply 1 or 2 is below the threshold value).
 The device is not operational.

The failure of the connection on at least one port.
The report of the link status can be masked by the Management for
each port. In the delivery state, is deactivated.
 Failure of the ring redundancy reserve.

Errors detected during the self-diagnostic test.
 Incorrect configuration of the HIPER-Ring or ring coupling.
The following condition is also reported in RM mode:

Ring redundancy reserve is available. On delivery, there is no ring
redundancy monitoring.
 Pull the terminal block off the device and connect the power supply
and signal lines.
52
Installation RS20/22/30/32/40
Release 05 12/2015