Emerson Hydrastep 2468 series - 3 C.3.2.4 Two out of Two Opto-Output Alarm System

Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034
3c-11
3c.3.2.4 ‘Two out of Two’ Opto-output Alarm System
This system requires both opto-outputs to operate to cause an alarm when their assigned
electrodes register an alarm condition.
Case A - Opto-output circuit normally open circuit, short circuit both to trip
TR2
(Switch SW5 is set to S for low level alarms and set to W for high level alarms)
Opto-output 1
TR2
Opto-output 1
+ VE - VE
Even Electrodes
(LH Input Board)
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
1
4
3
2
PL 2
1
4
3
2
PL 2
To alarm annunciator or
tripping device
Case B - Opto-output circuit normally short circuit, open circuit both to trip
TR2
(Switch SW5 is set to W for low level alarms and set to S for high level alarms)
Opto-output 1
TR2
Opto-output 1
+ VE - VE
Even Electrodes
(LH Input Board)
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
1
4
3
2
PL 2
1
4
3
2
PL 2
To alarm annunciator or
tripping device