The DCA has a graphical LCD display that is backlit and UV protected. There are two lines per sensor for standard sensor information. The top line displays the channel number, and temperature for DO, pH, and ORP sensors. The bottom line displays sensor type, reading, and units of the sensor.
The DCA will automatically recognize the sensor type (DO, SS, pH, or ORP) and configure itself for proper operation. The DO sensor will come factory calibrated and ready for use. The SS sensor is zeroed at the factory, and comes with a default calibration curve. The pH electrode is factory calibrated with its holder, and the ORP electrode is matched with its holder. To utilize factory calibrations for SS and pH, sensors must be connected to the analyzer and channel indicated per the “Factory Sensor Configuration” label located on the analyzer. Custom sensor configuration is available upon request.
The Optical DO sensor does not need sensor caps, membranes, fill solutions, nor routine calibrations and maintenance. The SS sensor is based on near infrared technology, which eliminates inaccuracies caused by changes in the process colour or changes in particle size. The pH sensor is flat glass / double reference junction temperature compensated construction with embedded electronics for reliable digital communications. The ORP sensor is flat surface platinum / double reference junction construction with embedded electronics for reliable digital communications.
Fluorescence Dissolved Oxygen —Theory of operation
A very specific energy wavelength is transmitted to a ruthenium compound immobilized in a sol-gel matrix. The ruthenium will absorb this energy, changing the outer electron’s energy level. The electron will then collapse back to its original energy state, emitting the energy as a photon with a different specific wavelength. This is called fluorescing. If the intensity of the transmitted wavelength is tightly controlled, the amount of fluorescing is both predictable and repeatable. If oxygen molecules are present the amount of fluorescing is reduced, referred to as fluorescence quenching. By measuring the amount of quenching it is possible to determine the amount of oxygen present.