CO2 MODBUS-Analogue Sensor with Controller Function
Most manufacturers have chosen to fit the sensor with an automatic recalibration mechanism, often referred to as an ABC algorithm. The idea behind this is that all buildings have times when they are not in use. At such times, the measured CO2 concentration in the building drops to a minimum value, which is almost identical to the known concentration in the outside air. This information can be used to recalibrate the sensor automatically and at regular intervals. Unfortunately, this method does not always produce good results in all buildings: the sensor only supplies reliable readings after a long period of adaptation to the building, which can take up to a week. In our sensors, the ABC algorithm is not used. Our sensors are recalibration-free and, once installed, are immediately ready for operation.
Our CO2 sensors are n-dir type and are built with dualbeam and dual wavelength receiving cuvette module so, no need calibration, making these devices ideal for offices where windows can not be opened: in hospitals, nurseries, kindergartens…
With this new sensor MODBUS-Analogue model, the user has all the digital and analog functions for measuring the concentration of CO2 in the air in one single device. For digital communication Modbus RTU, it can setup the baudrate, address, detection thresholds, triggers ... accessible through a console program with easy setup. The analog output is configurable to voltage 0 to 10V or to current 4-20mA. The sensor measures in the range of 400 to 4000 ppm but as a novelty, this sensor has an additional features as “Scaling Function” to give a proportional output scalable depending on the desired concentration, so that the user can connect any voltage/current in that scale relative to the ppm concentration measurement so that it can set the max voltage 10v output to 1200 ppm concentration and 0v to 600 ppm, for example. It also has a digital output solid state relay that it can also be configured with a trigger concentration and such as output’ type of NC/NA (normally open/closed) by the user.
As innovative, the device not only could work as SENSOR, it could work as PID Controller. On this working Mode, the advance user has to configure a Setpoint and controller parameters; Kp,Ki,Kd to determine the type of the desired Controller: proportional P, proportional-integrative P-I, and proportional-integrative-derivative, PID.
With all this new functionalities and working modes (sensor/controller) do this sensor very useful to connect it directly to any type of plant system: motorized air vents/grilles, dampers, variable fan speed control, adjustable air purification systems, etc...