Emerson Releases Rosemount 490A Optical Dissolved-Oxygen Sensor

Emerson recently released the Rosemount 490A Optical Dissolved-Oxygen Sensor, a digital, Modbus-enabled measurement device designed to enhance operational flexibility and simplify installation across 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 conditions. These sensors are often only capable of communicating process values via analog 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 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 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 reduce maintenance requirements compared to traditional amperometric sensors. Its two-year sensing cap lifespan minimizes downtime and associated costs, and it can be calibrated in free air.

Additionally, the chemically resistant, IP68-rated design ensures 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, 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 mg/L (0 to 20 mg/L) and ±2% (20 to 60 mg/L), ensuring precise monitoring and control of dissolved oxygen levels. It pairs with the Rosemount 1058 digital transmitter, which provides a range of measurement signals for compatibility with numerous host control systems.