4
CD-W00-00-0 Wall Mount CO
2
Transmitter Installation Instructions
Setup and Adjustments
Commissioning
Johnson Controls CO
2
transmitters come from the
factory calibrated for the following:
•
output signal (0 to 10V) proportional to CO2
concentration (0 to 2,000 ppm)
•
altitude range of 0 to 1,969 ft (0 to 600m)
above sea level without compensation
Altitude Compensation
The sensors are calibrated for an altitude of 984 ft
(300m) above sea level and are intended for
applications within the range of 0 to 1,969 ft
(0 to 600m) without compensation.
For altitudes above 1,969 ft (600m) where optimum
accuracy of the CO
2
concentration measurement is
essential, modify the Building Automation System
(BAS) controller’s Analog Input (AI) ranging to
compensate for sensor placement at other than the
standard calibration altitude.
To do this, reset the 2,000 ppm value using the
controller’s Compensation Factor (CF) shown in
Figure 8 or Figure 9, as follows:
Corrected Value = CF x 2,000
For example, if the sensor is situated at an altitude of
3,000 ft (914.4m) above sea level, the CF is 1.10
(see Figure 8 or Figure 9).
The new value is calculated as follows:
Corrected Value = (1.10)(2,000 ppm) = 2,200 ppm
CF
Altitude (Feet)
1.30
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
1,000
2,000
3,000
4,000
5,000
6,000
7,000
0
Figure 8: Altitude Compensation in Feet above Sea Level
CF
0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 2,200
Altitude (Meters)
1.15
1.10
1.05
1.00
0.95
0.90
1.20
1.25
1.30
Figure 9: Altitude Compensation in Meters above Sea Level
