Emerson 2468CB, 2468CD manual 3a-14

Relay Output Board Option Hydrastep 2468CB and 2468CD Manual

3a.3.2.6 ‘Two out of Three’ Relay Alarm System

In the following diagrams (7A & 7B)  indicate the electrode channel selected for each relay. A fully functioning system (NO FAULTS) will cause a low level trip at electrode level 2. Using high-level electrode channels and SW5 set to ES, the circuit can perform a high level trip. Note: Inputs from electrodes 1 & 2 are applied to two separate relays on their respective boards.

Case A - Relays normally energised, de-energise two to trip

		(Relays shown in de-energised state)
RL 1	1	PL 2	RL 1	1	PL 2
	2			2
3	3		2	3
	4			4	To alarm
					annunciator
	5			5	or tripping
					device
RL 2	6		RL 2	6
	7		2	7
1	8			8
RL 3	1		Even electrodes
			(LH input board)
	2
1	3
	4		Alarm off when contacts closed
Odd electrodes
(RH input board)		PL 3

(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 two to trip

	(Relays shown in de-energised state)
RL 1	PL 2	RL 1		PL 2
	1		1
	2		2
3	3	2	3
	4		4	To alarm
				annunciator
	5		5	or tripping
				device
RL 2	6	RL 2	6
	7	2	7
1	8		8
		Even electrodes
RL 3		(LH input board)
	1
	2
1	3
	4	Alarm off when contacts open
Odd electrodes	PL 3
(RH input board)

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

3a-14 24685034