ABB eVM1 Installation And Service Instructions Manual page 51

Fig. 36
The Second Safety Open is executed when DI 16, non-configurable, goes to high level "1" (voltage
on input higher than activation threshold, about 16...20V AC/DC) in two modes:
a) DSP is working and the WD signal is ok
the Second Safety Open Command is executed by DSP as a SW opening if there is no SW
blocking condition, i.e. when CB Open Disabling (for second Safety Open only) has not been
enabled in the configuration
OR DI4, # CB Open Disabling is not active, i.e. it is at high level "1";
b) DSP fails and the WD signal enables the HW block
the Second Safety Command is executed as a HW opening if dip switch I1-S1 is closed
(ON);
AND dip switch I1-S2 is open (OFF)
OR dip switch I1-S2 is closed (ON) and DI 4, # CB Open Disabling is not active, i.e. it
is at high level "1";
14.5.5.5.1 HW configuration
The Second Safety Open operating mode is selected by setting Dip-Switch I1 (S1...S2) on the
motherboard; by default I1-S1 is ON and I1-S2 is OFF, Second Safety Open HW block is enabled.
See figure below for I1 Dip switch location on the IED Motherboard
Fig. 37
49