Solid-state, optical technology oxygen sensors for eco monitors

November 17, 2016 // By Graham Prophet
From SST Sensing, the LuminOx sensor family uses solid state techniques to deliver sensors with the cost effectiveness found in commonly-used electrochemical oxygen sensors, but with a series of key additional benefits.

The optically-based, factory-calibrated LuminOx sensors rely on fluorescence quenching by oxygen. Pulsed light is directed onto an oxygen-sensitive dye causing it to fluoresce. The rate at which this fluorescence decays is inversely proportional to the amount of oxygen present in the vicinity. Because the phenomenon does not deplete the fluorescent dye, LuminOx devices can be deployed for far more prolonged periods than are possible using conventional oxygen sensors in this price bracket (which are normally based on electrochemical measurement mechanisms reliant on an electrolyte which is “consumed” over time). They can remain in service for well over 5 years. LuminOx sensors are completely free from lead, liquid electrolytes and other hazardous materials that are present in electrochemical sensing solutions.

 

LuminOx devices are suitable for measuring oxygen in terms of either partial pressure (ppO 2) or oxygen concentration (vol. %). LuminOx is fully compensated for temperature and barometric pressure. Running from a standard 5V supply, these sensors draw a current of under 6 mA when acquiring sampling data at a rate of 1 sample/sec. Standard sensors operate from 0-25% vol. O 2 and a high degree of accuracy is maintained across this range (with better than 2% full scale achieved). They support a working temperature range spanning from -30°C to +60°C, making them considerably more robust than competing devices. Providing a simple 3.3V TTL output across an RS232 serial interface, they can be connected directly to the system microcontroller with no need for additional signal conditioning electronics. The compact form factor of these sensors means that they can be used to replace older generation sensor devices while keeping the same housing format.

 

Typical applications types include - portable equipment, breathing apparatus, laboratory equipment, incubation systems, perishable goods transportation, combustion processes, agriculture, inerting and fire prevention.

 

SST Sensing (Coatbridge, Scotland); www.sstsensing.com