Emerson 2468CD, 2468CB manual 3b-15

Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option

3b.3.2.6 ‘Two out of Four’ Relay Alarm System (contd.)

In the following diagrams (6A & 6B)  indicate the electrode channel selected for each relay. A fully functioning system (NO FAULTS) will perform a low level trip at electrode level 2. For a high level trip, using electrode channels 9, 10, 11 and 12 respectively and switch SW5 set for ES, a healthy system would trip at level 11.

Case A - Relays normally energised, de-energise one in each pair to trip

(Relays shown in de-energised state)

RL 1	PL 2
	1
	2
3	3
	4
	5
RL 2	6
1	7
	8
Odd electrodes
(RH input board)

RL 1	PL 2
	1
	2
4	3
	4
	5
RL 2	6
2	7
	8
Even electrodes
(LH input board)

To alarm annunciator or tripping device

Alarm off when contacts closed

(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)

Case B - Relays normally de-energised, energise one in each pair to trip

(Relays shown in de-energised state)

RL 1

3

RL 2

1

Odd electrodes (RH input board)

PL 2

1

2

3

4

5

6

7

8

RL 1	1	PL 2
	2
4	3
	4	To alarm
		annunciator
	5	or tripping
		device
RL 2	6
2	7
	8
Even electrodes
(LH input board)

Alarm off when contacts open

(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)

24685034 3b-15