LR31

Supported Applications

The Omega EchoPro LR31 is an intrinsically safe, non-contact pulse radar level transmitter designed for continuous liquid level measurement in open channel and tank applications. The series targets industrial wastewater systems, municipal storm or sewer lift stations, reservoirs, rivers, canals, and sumps located below or above grade.

According to the product overview, the sensor is engineered to operate effectively despite challenging process conditions such as light surface foam, agitation, small trash, wind, condensation, or vapor. It utilizes a 26 GHz microwave pulse technology that measures time of flight from the antenna to the liquid surface and converts it into an analog output.

Operating Conditions & Performance

The LR31 provides continuous level measurement across a range of 12" to 98.4' (30cm to 30m) with a specified accuracy of ± 3mm and a beam angle of 12°. A dead band of 12" (30cm) is defined for the sensor operation.

Performance specifications include:

• Process Temperature: F: -40° to 212°, C: -40° to 100°
• Storage Temperature: F: -40° to 176°, C: -40° to 80°
• Pressure Rating: Atmospheric
• Power Supply: 21.6 to 26.4 VDC with a maximum consumption of 22.5 mA
• Signal Output: 4-20 mA, two-wire, HART 7 (configurable for signal invert: 4-20 mA or 20-4 mA)
• Fail-Safe Signals: Configurable at 3.9 mA, 20.5 mA, or 22 mA

The sensor features automatic temperature compensation and is housed in a Nylon enclosure with an IP68 rating.

Configuration Options

The LR31 series supports specific configuration options for mounting, cabling, and display integration. The standard assembly includes the sensor, bracket, cable, and display module.

• Mounting Options: 304 SS bracket or 1" NPT process mount
• Cable Specifications: 6-conductor, shielded with a PVC jacket; standard length is 32.8' (10m)
• Housing Materials: Nylon sensor enclosure and Polycarbonate display enclosure
• Display Module Features:
• Type: LCD, dot matrix with wall mount configuration
• Ratings: IP67 enclosure rating
• Units: Displays in Feet and meters; includes percent of span bar graph and echo signal curve
• Configuration Interface: Push button or HART 7 communicator
• Conduit Entrance: (2) 1/2" NPT connectors on the display unit
• Sensor Dimensions:
• Overall Height: 11.02" (280mm)
• Width: 5.12" (130mm)
• Base Diameter: 4.88" (124mm)

The series holds Intrinsically Safe classification with approvals including ATEX II 2G Ex ia IIC T6...T3 Ga, IEC Ex ia IIC T6...T3 Ga, and CSA Class I, Div 1 (Groups A, B, C & D); Class II, Div 1 (Groups E, F & G). Additional certifications include FCC, CE, and RoHS compliance.

Key Product Differences

The LR31 is distinguished within the EchoPro family by its specific focus on open channel applications using a bracket or top-mounted installation method. Unlike other series in the manual that utilize flange mounts (LR21, LR26) or NPT threaded connections for tank immersion (LR11, LR16), the LR31 is designed to be suspended above the liquid via a 304 SS bracket.

Model numbering follows the format LR31---. The standard stocked variant (LR31-0021-10-00) includes the sensor, mounting bracket, 32.8' cable, and display module.