2
Fig. 4 Wiring
Transformer
24VAC
1 2 4 5
<240VAC/30VDC/2A
Transformer
supply
Power
3
device
Controlled
L2
L1
General
CO2
mA
4-20mA
Connection
Terminal Function Electrical Data
1G+ Power (+) 24VAC/24VDC+
2G0 Power ground (-) 24VAC/24VDC
3OUT Analog output (+) 0–10VDC (default), 2–10VDC, 0–20mA,
4–20mA=0–2,000 ppm (CO2)
4Fan Relay output <240VAC/30VDC 2A switching
current (resistance load)
5Common
SELECT OUTPUT
IMPORTANT INSTRUCTIONS
• Power off first and remove the face cover, you’ll see a
set of short-circuit block jumpers in the middle of the
right side of PCB board. From left to right, it’ s J1–J5
and S1–S2. Choose the type of analogue output or
CO2level to control the relay following instructions
shown in table shown in table below (J2 & J3 are just
for manufacture test. Please don’ t change it!).
1. Don’t shake or hit the sensor too much during shipment or mounting to protect the internal infrared CO2sensor from
any damage and excursion of infrared receiver.
2. When:
a. First use CO2sensor, or
b. Reuse CO2sensor after a long time unused or
c. CO2measurement is proved to be incorrect (by comparing with the measurement of other CO2sensors,
or put the sensor outdoors and its measurement is away from the range of 350ppm–450ppm, which is the normal
ambient CO2concentration, then let the self-calibration system work as follows:
Keep the CO2sensor energized continuously for at least 2 days to let CO2sensor’s self-calibration system operate properly.
After more than 2 days’ calibration, if the measurement (indicated by the analog output) of the
CO2sensor still exceeds over the accuracy, you need to let it self-calibrated for a longer time. Here’s a typical
14-day calibration solution: During a 14-day period, place the CO2sensor twice outdoors or in unoccupied places where
CO2level is around 400 ppm. Each time let it be there for more than 4 hours and then check the CO2measurement via
analogue output. If the CO2measurement is in its accuracy limit, it indicates the measurement is correct.
Notice:
a. Using of cellular telephones or radio transceivers about 60 cm away from the sensor during calibration process could
cause sensor interference, calibration errors and affect sensor accuracy. Please refrain from using these devices during
calibration of the sensor.
b. When checking the analog output, please avoid breathing out directly to the CO2sensor. It’s recommended to connect
the output terminals with the extending wires with length of more than 1 meter. When the CO2sensor indications become
stable after more than 10 minutes turning-on, check the analog output through the extending wires to avoid influence of
breathing process on CO2concentration.
Jumper S1-S2 Jumper J1 Analog outputs
Lower two pins blocked disconnected 0–10VDC (default)
Upper two pins blocked disconnected 0–20mA
Lower two pins blocked connected 2–10VDC
Upper two pins blocked connected 4–20mA
Jumper J4-J5 CO2level The relay turns on /turns off
J4-disconnected; J5-disconnected 800 ppm CO2>800 ppm, the relay on; CO2<700 ppm, the relay off
J4-connected; J5-disconnected 1,000 ppm CO2>1,000 ppm, the relay on; CO2<900 ppm, the relay off
J4-disconnected; J5-connected 1,200 ppm (default) CO2>1,200 ppm, the relay on; CO2<1,100 ppm, the relay off
J4-connected; J5-connected 1,400 ppm CO2>1,400 ppm, the relay on; CO2<1,300 ppm, the relay off
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