3A.3.2.5 'Two Out Of Four' Relay Alarm System - Emerson Hydrastep 2468 series Operating Manual

Relay Output Board Option

3a.3.2.5 'Two out of Four' Relay Alarm System

In the following diagrams (5A & 5B)
each relay. A fully functioning system (NO FAULTS) will perform a low level trip at electrode
level 3. For a high level trip, using electrode channels 11, 12, 9 and 10 respectively and
switch SW5 set for ES, a healthy system would trip at level 10.
Case A - Relays normally energised, de-energise one in each pair to trip
(Relays shown in de-energised state)
RL 1
3
RL 2
1
Odd electrodes
(RH input board)
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
Case B - Relays normally energised, de-energise one pair to trip
(Relays shown in de-energised state)
RL 1
3
RL 2
1
Odd electrodes
(RH input board)
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
3a-12

PL 2
1
2
4
3
4
5
6
7
2
8
Even electrodes
(LH input board)
Alarm off when contacts open
PL 2
1
2
4
3
4
5
6
7
2
8
Even electrodes
(LH input board)
Alarm off when contacts open
Hydrastep 2468CB and 2468CD Manual
indicate the electrode channel selected for
PL 2
RL 1
1
2
3
4
5
RL 2
6
7
8
PL 2
RL 1
1
2
3
4
5
RL 2
6
7
8
To alarm
annunciator
or tripping
device
To alarm
annunciator
or tripping
device
24685034