R36US0002EU0100 Rev 1.00
Page 7
Aug 26, 2021
RTD120D-EVK Evaluation Kit Software Manual
2.4 Monitoring CO
2
Concentration and Sensor Readings
After communication is established, the GUI will display live graphs of the CO
2
Concentration and readings of the
other sensors on the board. To manipulate the scale and depth of the data displayed in these graphs, refer to the
DAQFactory help guides, which can be accessed from the Help menu.
2.5 Calibration Using DAQFactory
The EVK is pre-calibrated but it can be re-calibrated if desired. Calibration can be performed in either of two ways:
▪ In a stand-alone fashion, using the LCD and push-button user interface on the EVK itself
▪ With a GUI, using a connected PC for a more interactive and visual experience
This section describes the GUI-based method of CO
2
calibration. To calibrate the kit without using a connected
host computer (instead using the LCD and pushbutton UI), see the
RTD120D-EVK CO
2
EVK User Manual
.
2.5.1
General Calibration Principles
The EVK continuously reads the two thermopile channels, reading each channel once with the lamp ON and once
with the lamp OFF, resulting in four readings. After each such sequence, a “raw” value (a positive integer typically
between a few hundred and a few thousand) is calculated from the four readings. The sequence occurs every
5 seconds, so a “raw” value is always available in the microcontroller’s memory to be used for further processing,
