PROGRAMMING OF IAQRAE
4-11
6. Turn gas flow off. Disconnect calibration tube from monitor.
Calibration Time Stamp
When a single sensor calibration is performed, a time stamp
will be stored in nonvolatile memory. This information will be
included in the Datalogging report.
CO
2
Sensor Calibration
CO
2
sensor calibration is different from calibrating other
sensors. During fresh air calibration, the CO
2
sensor does not
do anything. It must be zeroed in the single sensor calibration
menu. The CO
2
sensor can be span calibrated in either single
sensor mode or multiple sensor mode.
During single sensor calibration, the user should supply pure
air or nitrogen gas from a cylinder or 10 ppm isobutylene to
zero the CO
2
sensor. The user may also supply a span
concentration of CO
2
, (~5,000 ppm) to calibrate the CO
2
sensor. When the monitor asks “0% CO
2
?” press [Y/+] if CO
2
-
free gas is being used to zero calibrate the CO
2
sensor.
During either single or multiple sensor calibration, the CO
2
sensor will be calibrated to the span value defined in Section
4.2.4. However, it is good practice to perform zero calibration
before span calibration.
Note:
After a 0% CO
2
calibration, the user must perform a
span calibration to ensure that the CO
2
sensor has been
calibrated correctly.
Temperature Sensor Calibration
The temperature sensor does not need zeroing and may be
calibrated in either Single Sensor or Multiple Sensor Calibration
menus. Annual calibration is usually adequate. To calibrate,
first let the monitor equilibrate to the ambient temperature for at
least 30 minutes. Measure the ambient temperature with a
thermometer, then set the span temperature to the measured
value as mentioned in Section 4.2.4.
During single sensor calibration, use [MODE] to select the
temperature sensor. Press [Y/+] to start calibration. After 10
seconds, “Temp Cal’ed” and temperature reading will appear.
