Product Introduction
1. Alphasense NDIR Evaluation Board IRC-TX Description
Alphasense NDIR Evaluation BoardIt can be used by users to evaluate two AlphasenseIRC-A1NDIR sensors. The board can be powered by internal batteries or an external power supply, providing user-defined amplitude and frequency of the appropriate lamp drive signal.
The raw outputs of the sensor's active and reference channels are filtered and amplified, and the amplitude of the AC component is output as a DC signal.
2. Alphasense NDIR Evaluation Board IRC-TX Power Supply
Power can be supplied internally via 2 x C cell batteries, or externally with 6-12V DC 200mA. If using batteries, the ON/OFF switch on the board is used to turn the device on and off. If using an external power supply, the ON/OFF switch becomes redundant, and the device must be turned off by disconnecting the external power.
3. Alphasense NDIR Evaluation Board IRC-TX Sensor Installation
It is recommended to power off the device when installing or removing sensors. Sensors should be pressed firmly into the SN1 and SN2 sockets. It is not necessary to install both sensors for operation; if only one sensor is available, it can be inserted into either socket.
4. Alphasense NDIR Evaluation Board IRC-TX Setting Drive Voltage and Frequency
The Alphasense NDIR evaluation board supplies power to the lamp in the form of a square wave. The factory-set amplitude and frequency are 5V and 2.0Hz. However, the lamp drive amplitude and frequency can be changed via potentiometers on the board. The drive signal can be measured between AGND and drive A (or B) pins using an oscilloscope or other suitable measurement equipment. The drive voltage can be continuously varied from 0 to 5V, and the drive frequency can be changed from 1.0Hz to 2.75Hz in 0.25Hz steps.
5. Alphasense NDIR Evaluation Board IRC-TX On-Board Outputs
Active and reference channel signals
The raw sensor output consists of a DC offset superimposed with an AC signal consistent with the lamp drive. The useful component is the amplitude of the AC component.
6. Alphasense NDIR Evaluation Board IRC-TX Thermistor Output
The thermistor screw terminal (labeled TH) provides direct output from the internal thermistor of the IRC-A NDIR sensor. To use the thermistor output, a reference voltage must be applied through a resistor to the thermistor output. Then, the voltage between the thermistor output and ground is used to determine the thermistor resistance and temperature (refer to Application Note AAN202-01).
