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Chapter 4
Alarm Systems
4.1 Alarm Monitoring System
The models OPR300-24S and OPR300-24R have the ability to monitor output DC voltage, and
trigger an alarm when the output DC voltage starts to decrease below the threshold limit. The
power supply models have a threshold limit of 20VDC.
OPR300-24S Alarm Indications
If for some reason the voltages in power supply Model OPR300-24S drop below the threshold
limit (due to overload, for example) the DB25 interface pin 16 will go logic LOW, and pin 3 will
have logic HIGH indicating power supply failure.
DB25 Pin Out
Normal Condition
Power Supply Failure
Pin 16
(Power Supply Alarm)
Logic High = 1
Logic Low = 0
Pin 3
(Power Supply Alarm)
Logic Low = 0
Logic High = 1
OPR300-24R Alarm Indications
If for some reason the voltages of power supply 1 in the Model OPR300-24R drop below the
threshold limit (due to overload, for example) the DB25 interface pins 3 will go logic HIGH, and
pin 16 will have logic LOW indicating power supply 1 failure.
DB25 Pin Out
Normal Condition
Power Supply Failure
Pin 3
(Power Supply 1 Alarm)
Logic Low = 0
Logic High = 1
Pin 16
(Power Supply 1 Alarm)
Logic High = 1
Logic Low = 0
Furthermore, if the voltages of power supply 2 drop below the threshold limit. The interface pin
17 will go logic HIGH, and pin 9 will have logic LOW indicating power supply 2 failure.
DB25 Pin Out
Normal Condition
Power Supply Failure
Pin 17
(Power Supply 2 Alarm)
Logic Low = 0
Logic High = 1
Pin 9
(Power Supply 2 Alarm)
Logic High = 1
Logic Low = 0
