THE NET AUTOMATIC CALIBRATION SYSTEM

To ensure maximum accuracy and dependability, here at NET each NDIR sensor is individually calibrated. An automatic system designed and built in-house allow us to complete long and complexes cycles for up to 144 sensors per batch without requiring constant attention by an operator, while ensuring consistency of results and storage of an ever-increasing data base of information.

For each type of sensor in our range, we have defined an individual calibration cycle. That is, a specific sequence of gas concentration steps across the desired measuring range, repeated over a number of temperature/relative humidity condition combinations within an environmental chamber. At every step, signal data from each individual sensor is stored by the system. At the end of the process, this allows us to determine the optimal linearization curve of each sensor guaranteeing the best performances across the measuring and environmental ranges.

The gas is circulated within a system of tubes and conduits directly connected with the sensors, optimizing the amount of required gas and avoiding dispersion in the environment. Each sensor is wired into a transmitter directly connected to the controlling computer.

A calibration cycle can last from a few hours up to several days, and our automatic system allow us to concentrate other tasks while the sensors receive their calibration. The status of the process is continuously monitored, and critical information is displayed on the controlling computer screen. At a glance, our personnel can check if the process is under control and if it needs any correction.

Each system is composed of a computer running a proprietary software, controlling automatically the 3 key elements:

• The climatic chamber, generating temperature and relative humidity conditions across the full sensor functioning range.
• The mass-flow controllers, precisely regulating gas release at specific concentration steps required by the calibration cycle. The mass flow controllers can not only control the release from a calibration cylinder, but also mix gases to create a desired concentration, different from the one in the cylinder.
• Each sensor involved in the calibration process, through its individual transmitter.