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6. External Control Wiring
The pin numbers for the external output connector are num-
bered from 1 to 6. Pin 1 is the closest pin to the power jack.
The pin designations are as follows:
1.
12 V DC
2.
Analogue output 0-5 V
3.
Control
4.
High alarm
5.
Low alarm
6.
Ground
The RJ12 connector offers two possibilities for wiring, either a
switch to GND or a 12V output. If the 12V output is used, the
power for the relay coil is supplied by the Aeroqual AC/DC
adaptor. In this case, ensure that the relay coil does not draw
more than 150mA and that a protection diode is inserted
across the relay coil.
If the switch to GND output is used, ensure that the relay coil
does not draw more than 150mA, that the voltage does not
exceed 24V and that a protection diode is inserted across the
relay coil.
Wiring for alarm
The high alarm and low alarm pins can be wired to supply sim-
ple on / off switching to operate equipment which requires only
an on or off signal, such as an alarm.
To switch to GND use pins 4, 5 and 6. For a 12V output wire
to pins 4, 5 and 1 (see the following diagram for typical wiring
for high alarm). This feature will only operate while powered by
the AC adaptor. The factory default settings are based on the
gas sensor head selected at time of purchase.