Emerson 2468CD, 2468CB manual 3c-13

Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option

3c.3.2.6 ‘Two out of Three’ Opto-output Alarm System

In the following diagrams (6A & 6B)  indicate the electrode channel selected for each opto- output. 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 S, the circuit can perform a high level trip.

Note: Inputs from electrodes 1 & 2 are applied to two separate opto-outputs on their respective boards.

Case A - Opto-output circuit normally open circuit, short circuit two to trip

		PL 2				PL 2	External power must
TR2	3	1	TR2	2	1	Note:
							be applied as shown.
		2			2		See specification for
							power requirements
		3			3
Opto-output 1		4	Opto-output 1		4		+ VE
		5			5		To alarm
TR4	1		TR4	2			annunciator
		6					or tripping
					6		device
		7			7		- VE
Opto-output 2		8	Opto-output 2		8
			Even Electrodes
TR6	1	1	(LH Input Board)
		2
		3
Opto-output 3		4
Odd Electrodes
(RH Input Board)		PL 3

(Switch SW5 is set to S for low level alarms and set to W for high level alarms)

Case B - Opto-output circuit normally short circuit, open circuit to trip

		PL 2				PL 2	External power must
TR2	3	1	TR2	2	1	Note:
							be applied as shown.
		2			2		See specification for
							power requirements
		3			3
Opto-output 1		4	Opto-output 1		4		+ VE
TR4		5			5		To alarm
	1		TR4	2			annunciator
		6					or tripping
					6		device
		7			7		- VE
Opto-output 2		8	Opto-output 2		8
			Even Electrodes
TR6	1	1	(LH Input Board)
		2
		3
Opto-output 3		4
Odd Electrodes
(RH Input Board)		PL 3

(Switch SW5 is set to W for low level alarms and set to S for high level alarms)

24685034 3c-13