FCX-MLD: Digital, compact oxygen gas sensing module
Oxygen controlled atmosphere (CA) applications in some cases rely on a long, stable operational lifetime of the oxygen sensing module and in some cases on a sufficiently high signal resolution in a wide range of oxygen concentrations. The FCX-U series of amperometric, zirconia oxygen sensors combines both – stable long lifetimes >> 3 years and high signal resolution < 10-200 ppm are generally guaranteed, depending on which exact sensor element is chosen. Pewatron has developed a digital and very compact oxygen gas sensing module that controls the FCX-U element and deliver a 10-bit serial output low-noise signal. One intended application of the module is for example oxygen control in storage facilities with potentially dangerous chemicals and gases and where the oxygen concentration needs to be lowered in order to prevent explosions/fires or where a sufficiently high amount of oxygen need to be guaranteed for safe operation in the facility.
The FCX-U oxygen sensing element, i.e. the amperometric zirconia oxygen sensor, can be chosen from 2 different measurement ranges; 0…25 %Vol (FCX-UC) & 0,1…95 %Vol (FCX-UWC). The choice of the sensor element depends on the exact application; for safety driven applications, the FCX-UC 25 %Vol sensor is the best choice, because this sensor can be operated in a range from 1000 ppm and up to 25% with a very high stability. On the other hand, the FCX-UWC 95 %Vol sensor is a good choice for oxygen concentrator applications, because the signal resolution of the amperometric sensor at oxygen concentrations > 70 %Vol is very high. The measurement range of the FCX-UWC sensor can for instance be set between 20 %Vol (air) and 95 %Vol, so that the signal resolution is maximized and the sensor check in air is made easy.
The MLD electronics is an OEM electronics with serial digital output (3.3 V TTL level). The serial communication have features for control and read-out of the oxygen concentration. Read-out of the oxygen concentration can be set by command to be continuous or in a defined time interval between 0.1 and 9.9 seconds. The sensor can be turned on and off by command and the zero-point and full-scale calibration points can be adjusted also by read-&-write commands. The MLD electronics measures only 48 x 38 mm and the height (including potentiometers and oxygen sensor) is < 26 mm. The compactness of the module enable integration of the module directly into an application or limit the space requirements for build-in into an application. The OEM electronics can also be delivered in either metallic or plastic enclosures for easy integration into existing electronic mounting racks.
