Filter
Top Products
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034
3b-13
3b.3.2.4 ‘Two out of Two’ Relay Alarm System
This system requires both relays to operate to cause an alarm when their assigned
electrodes register an alarm condition.
Case A - Relays normally energised, de-energise both to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Case B - Relays normally de-energised, energise both to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2