Optical Dissolved Oxygen Sensor Features Increased Fouling Resistance

Emerson Process Management introduces the Rosemount Analytical RDO optical dissolved oxygen sensor and analyzer for use in wastewater aeration basins and ponds. The sensor is more resistant to fouling than polarographic sensors, an important advantage in wastewater where coating is a common problem. Less sensitivity to fouling means less need for cleaning and reduced operating costs. The sensor is available with either integral or quick-disconnect cable. A 1-¼ in FPT fitting at the rear of the sensor allows a threaded pipe to be screwed into the sensor so it can be submerged in the basin. The sensor’s design does not need a flowing sample, making it ideal for a low-flow basin or pond. Maintenance consists primarily of replacing the sensing cap once a year. The analyzer accepts one or two sensors. It has a two-line display, which can be customized to show mg/L (ppm) oxygen, percent saturation, oxygen partial pressure or temperature for either sensor. The display also can be configured to show the current barometric pressure. The analyzer has two loop-powered 4-20 mA analog outputs assignable to either sensor and to any measurement (concentration, temperature, or partial pressure). Modbus/ RS485 communication is also available as a standard feature. Calibration can be done either against a referee instrument or in water-saturated air. Air calibration is completely automatic.