Issue
Can SLPSXC2 CO2 sensor calibration be used with both methods (ABC standard and Fresh Air process) at the same time?
Product Line
Field Devices.
Environment
Building Operation SmartX Living Space Sensor.
Cause
SLPSXC2 CO2 can be calibrated using two different methods.
- Automatic Baseline Calibration(ABC)
The ABC algorithm constantly keeps track of the sensor’s lowest reading over a pre-configured time interval and slowly corrects for any long-term drift detected when compared to the expected fresh air value of 400 ppm.
ABC calibration is enabled/disabled through coil 4 (invoke = enable ABC).
- Manual Calibration
Coil 11 triggers the manual calibration (FRC 400ppm) => this will tell the sensor that the current level of CO2 should be interpreted as 400ppm.
When setting this register to 1, it automatically goes back to 0 a couple of seconds later.
Setting Coil 11 to value 1 is the same as pressing the calibration button.
Resolution
The both methods of calibration can be used simultaneously since one method is for correcting drift over time (1 week intervals), the other is a manually executed reset.
The only error would come if the unit was exposed to high CO2 concentrations at night, inducing abnormal averages. If ABC is disabled, manual calibration would need to be performed more frequently.
