LR21

Supported Applications

The Omega EchoPro® LR21 is an intrinsically safe, flange-mounted pulse radar level transmitter designed for continuous liquid level measurement in chemical storage and process tanks. It operates as a non-contact sensor suitable for above or below grade installations where conditions include corrosive media, light surface foam, agitation, higher temperature or pressure, condensation, vapor, or aggressive liquids under extremely difficult process conditions.

Operating Conditions & Performance

The LR21 series utilizes 26 GHz pulse radar technology to measure levels within a range of 12" to 65.6' (30cm to 20m), with an accuracy of ± 3mm and a dead band of 12" (30cm). The sensor is rated for process temperatures from -40° to 302°F (-40° to 150°C) and storage temperatures from -40° to 176°F (-40° to 80°C). It operates within a pressure range of -14.5 to 72 psi (-1 to 5 bar).

Electrical performance includes an IP67 enclosure rating, with power supplied via 21.6 to 26.4 VDC and maximum consumption at 22.5 mA. The unit features automatic temperature compensation.

Intrinsically Safe Approvals

The LR21 holds the following certifications for hazardous locations:

• ATEX II 1G Ex ia IIC T6...T3 Ga
• IECEx ia IIC T6...T3 Ga
• CSA Class I, Div 1, Groups A, B, C & D; Class II, Div 1, Groups E, F & G (T6...T3)
• Class I Zone 0 AEx ia IIC (T6...T3) Ga
• Zone 20 AEx ia IIIC (T76°C to T146°C) Da
• FCC, CE, CRN, and RoHS compliance

Configuration Options

The LR21 series is configured for specific flange mounting requirements. The housing material consists of 316L stainless steel with a silicone gasket, while the antenna features 316L stainless steel with a PTFE inner shield.

Process Connections and Dimensions

The series supports two primary process connection options:

• -30 Code (3" ANSI Flange): Features a 12° beam angle. The flange diameter is 7.5" (190.5mm) with a thickness of 0.88" (22.3mm). Overall height D measures 9" (228.6mm).
• -40 Code (4" ANSI Flange): Features an 8° beam angle. The flange diameter is 9" (228.6mm) with a thickness of 0.88" (22.3mm). Overall height D measures 10.5" (266.7mm).

Both configurations include an antenna diameter of 3.5" (88.9mm), an antenna height of 5.38" (136.5mm), and a single 1/2" NPT conduit entrance.

Output Signals and Configuration

The transmitter provides a two-wire output signal configurable as:

• 4-20 mA with HART 7 digital communication
• Inverted fail-safe options: 4-20 mA or 20-4 mA
• Fail-safe current settings at 3.9 mA, 20.5 mA, or 22 mA

Configuration is performed via an integral push button display module featuring a dot matrix LCD that shows feet and meters, percent of span bar graph, and echo signal curve visualization. Alternatively, the unit can be configured using a HART communicator.

Options and Accessories

The series supports optional accessories including:

• L124-1001 DATALOOP™ Intrinsically Safe Level Indicator
• HART Communicator for remote configuration

Key Product Differences

The primary variation within the LR21 series is defined by the flange size and corresponding beam angle. The -30 variant utilizes a 3" ANSI flange with a wider 12° beam, while the -40 variant uses a 4" ANSI flange providing a narrower 8° beam for improved resolution in specific tank geometries.

Performance limitations may occur if air particulates have high dielectric constants (e.g., lead or ferroalloy), highly dense particulates attenuate microwave signals, material builds up on the antenna, or mediums possess extremely low dielectric constant values with little reflectivity.