New digital dissolved oxygen sensor enhances operational versatility with lower maintenance costs

Emerson has announced the release of the Rosemount™ 490A Optical Dissolved Oxygen Sensor, a digital Modbus-enabled measurement device designed to enhance operational flexibility, simplify installation and reduce maintenance costs across many industrial applications in the water/wastewater treatment, biopharmaceutical manufacturing, food and beverage processing, and steam power generation industries.

Most dissolved oxygen probes for industrial applications are made for installation in specific and relatively benign conditions. These sensors are often only capable of communicating process values via analogue signals to control systems, and they require frequent calibration to maintain accuracy and avoid sensor drift.

To address these and other issues, the Rosemount 490A provides reliable and accurate dissolved oxygen measurements in demanding environments, while simplifying integration into existing control systems with digital and universal Modbus RTU communication via an accompanying transmitter. In addition to producing accurate readings within just 90 seconds of transition from dry to wet conditions, this versatile sensor is capable of measuring process media in both liquid and gas phases, without requiring separate calibrations.

The Rosemount 490A employs Environmental Protection Agency-approved luminescence-quenching technology, eliminating the need for electrolyte refills to significantly reduce maintenance requirements compared to traditional amperometric sensors. Its two-year sensing cap lifespan further minimizes downtime and associated costs, and it can be calibrated in free air.

Additionally, the chemically resistant IP68-rated design ensures reliable performance in challenging environments. Its small form factor, coupled with forward and rear facing 1-inch NPT threaded connections, simplifies installation in a variety of settings.

Unlike amperometric sensors, the 490A uses an optical sensor, which does not consume oxygen or require water flow for accurate measurements. Furthermore, versatile guard cap options provide weighted orientation, anti-fouling protection, and air blast cleaning, catering to a wide breadth of applications.

The sensor is accurate to ±0.1 milligram per litre (0 to 20 mg/L) and ±2% (20 to 60 mg/L), ensuring precise monitoring and control of dissolved oxygen levels. It seamlessly pairs with the

Rosemount 1058 digital transmitter, which provides a diverse range of measurement signals for compatibility with numerous host control systems.