CO2 sensors have been installed on the VAV boxes that have a 0-10 volt output, but the Xenta 102-AX is limited to reading 0-5 volt output using the Universal Inputs on the controller. If replacing the sensors would be too costly and time consuming, this is a viable option that will allow you to drop the voltage output on the CO2 sensor using 1000 ohm resistors.
TAC Vista, EcoStruxure Building Operation
CO2 sensors have been installed on the VAV boxes that have a 0-10 volt output but the 102-AX is limited to reading 0-5 volt output using the Universal Inputs on the controller.
NOTE: It is recommended that the incorrect sensors be removed and replaced with new sensors that have the proper specifications to match the 102-AX capabilities. If the sensor replacement is not an option please follow the instructions below.
Please see the image below:
- You will need (2) 1000 ohm (1k) resistors to complete this conversion.
- Wire one resistor directly to the output wire of the CO2 sensor
- Land that resistor to U3 on the 102-AX
- Jump a second resistor from U3 over to M on the 102-AX
- Land the other output wire from your CO2 sensor on M with the jumped resistor
Also see Using a 4-20mA CO2 sensor with a Xenta 102-AX to configure the Xenta 102-AX to accept a 4-20mA CO2 sensor input on Universal Input 3.