Calibration
The default sensor OEM unit is maintenance free in normal environments thanks to the built-in self-correcting ABC
algorithm (Automatic Baseline Correction). This algorithm constantly keeps track of the sensor’s lowest reading over a
7 days interval and slowly corrects for any long-term drift detected as compared to the expected fresh air value of 400
ppm CO2.
Rough handling and transportation might, however, result in a reduction of sensor reading accuracy. With time, the
ABC function will tune the readings back to the correct numbers. The default “tuning speed” is however limited to
about 30 ppm/week. For post calibration convenience, in the event that one cannot wait for the ABC algorithm to cure
any calibration offset, jumper 3 is provided for the operator to choose calibration options.
If jumper 3 is placed on position 1-2, for a minimum time of 8 seconds, the internal zero calibration is executed, in
which case the sensor must be purged by some gas mixture free from CO2 (i.e. Nitrogen or Soda Lime CO2 scrubbed
air). The air quality LED is blinking in green color alternately with the status LED in 2 second intervals.
If jumper 3 Is placed on position 3-4, it is assumed that the sensor is operating in a fresh air environment (400 ppm
CO2). The air quality LED is blinking in red color alternately with the status LED in 2 second intervals.
If unsuccessful, please wait at least 1 minute before repeating the procedure again. Make sure that the sensor
environment is steady and calm!
Make sure to return jumper 3 to its default position of 2 - 3!
Zero calibration procedure
The zero calibration procedure is as follow:
1. Connect the sensor on top with a tube (soft tubing 2x4 mm) and a
nipple (nylon tubing 30x0.8x2.2 mm), see Figure 4 below. There
are 2 alternative positions for nipple attachment.
2. Let a gas mixture flow into the sensor through the applied tube.
The flow shall be in the range of 0.3 – 1.0 liter/minute during 3
minutes. Keep the gas mixture flowing during the whole procedure.
3. Set jumper 3 to position 1-2 for a minimum time of 8 seconds. The
air quality LED will blink in green color alternating with the status
led in 2 second intervals.
4. Verify the zero calibration using the OPA-S or the analog outputs.
They should show 0 ppm CO2.
5. If zero calibration is not executed (sensor detected unstable gas
concentration) wait 10 sec and repeat steps 3 and 4 again. Do not
breathe on the sensor!
Insight Control
Ph 1300 665 831
www.insightcontrol.net.au
