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Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034
3c-13
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
1
4
3
2
5
8
7
6
TR2
PL 2
(Switch SW5 is set to S for low level alarms and set to W for high level alarms)
Opto-output 1
TR4
Opto-output 2
+ VE
- VE
To alarm
annunciator
or tripping
device
1
4
3
2
5
8
7
6
TR2
Opto-output 1
TR4
Opto-output 2
PL 2
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
Even Electrodes
(LH Input Board)
2
3
1
2
1
4
3
2
TR6
Opto-output 3
1
PL 3
Case B - Opto-output circuit normally short circuit, open circuit to trip
1
4
3
2
5
8
7
6
TR2
PL 2
(Switch SW5 is set to W for low level alarms and set to S for high level alarms)
Opto-output 1
TR4
Opto-output 2
+ VE
- VE
To alarm
annunciator
or tripping
device
1
4
3
2
5
8
7
6
TR2
Opto-output 1
TR4
Opto-output 2
PL 2
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
Even Electrodes
(LH Input Board)
2
3
1
2
1
4
3
2
TR6
Opto-output 3
1
PL 3