Hioki LR8431, Instruction Manual, Page: 142 / 204

9.4 Alarm Signal Output (Alarm Output)
134
This signal is output when alarm criteria are satisfied. Specify the desired alarm criteria.
See: 4.2, "Alarm Output" (p. 73)
9.4 Alarm Signal Output (Alarm Output)
Alarm signal output
(ALARM)
When alarm criteria are satisfied
About the Alarm Output Signal
Output signal Open-drain output (with voltage output), active LOW
Output voltage range HIGH level: 4.0 to 5.0 V, LOW level: 0 to 0.5 V
Output Refresh Every recording interval
Maximum input voltage 30 V DC, 5 mA max, 200 mW max
GND
ALARM
10 k

5 V
For the connection
method (p. 130)
Connect the ALARM (No. 4) and GND (No. 1) terminals of the
external control terminal block to the signal output line and
ground, respectively. When the alarm criteria are satisfied, a
Low level (0 to 0.5V) signal is output.
The ALARM pin implements active-low operation. In the example connection, current flows to the
coil when there is no alarm output. Choose a relay with a contact architecture that implements the
desired operation.
Relay
FET, etc.
GND
GND
ALARM
10 k

5 V DC
Instrument
DC power supply
(Provide a DC power supply that accom-
modates the relay coil's rated voltage.)
ALARM pin circuit architecture and example relay connection