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RU Flex 2100 Digital Level Sensor

RU Flex 2100 Digital Level Sensor

Categories: Digital Level Sensors (DLS)

The patent-pending RU Flex 2100 DLS is a flexible, extremely rugged, chemically and abrasion resistant digital level sensor offering continuous, accurate, and reliable monitoring of tank level and temperature. With an 18” flexible radius, one person can install the sensor in 15 minutes. Increased measurement accuracy (3/16" when ordered with 1/8" resolution) makes this sensor ready for more stringent API 18.2 measurement requirements.

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(Please include all of the specifications from the Configuration Options below on your RFQ)

The patent-pending RU Flex 2100 DLS is a flexible, extremely rugged, chemically and abrasion resistant digital level sensor offering continuous, accurate, and reliable monitoring of tank level and temperature. Using Electrolab’s proven, patented sensing technology housed in an Ultra High Molecular Weight Polyethelene tube, this sensor offers an 18” flexible radius allowing for one person to install the sensor. ALL sensor components fit in one box, which can ship standard carrier to your location. Increased measurement accuracy, 3/16" when ordered with 1/8" resolution, makes this sensor ready for more stringent API 18.2 measurement requirements.

Reliable— No Ongoing Calibration

After installing the sensor hardware and setting your initial level offset, these sensors require no additional calibration. All electronics, with the exception of the optional fuse board, are sealed inside the sensor tube, which is constructed of rugged, abrasion resistent UHMW. The apparatus is intrinsically safe (when used with a qualified intrinsically Safe Barrier, such as Electrolab’s 2110 Barrier Unit.) The RU Flex 2100 DLS offers low power consumption and is virtually maintenance free.

More Versatile and Reliable than Guided-Wave Radar

Electrolab’s RU Flex 2100 DLS offers greater versatility, flexibility and more robust features than conventional guided-wave radar (GWR) level sensors. A dual float sensor measures multiple fluid levels and temperature measurements through a SINGLE TANK PORT, eliminating the need for multiple sensors in one tank. To accomplish these same measurement and alarm protections, GWR requires two separate ports in a tank. This single device can also read up to eight distinct temperature measurements.

Unlike radar, this sensor is not affected by electro-mechanical interference, tank turbulence or changing environmental variables. Simply install the sensor, set your initial level offset and the RU Flex 2100 DLS is ready to monitor your tank. Under normal operating conditions, no additional calibration is needed—EVER. Ongoing maintence is practically non-existent. The naturally oleophobic non-stick nature of the UHMW prevents buildup on the sensor and prevents floats from sticking and impacting measurement accuracy. Cleaning of the RU Flex 2100 DLS is rarely necessary.

Flexible and Easy to Install

The RU Flex 2100 DLS offers all the benefits of Electrolab’s Model 2100 Digital Level Sensor with the added flexibility of a bendable material that can be coiled to an 18” radius. This means the sensor can fit neatly in a box for shipping and storage. All components (sensor, housing, cord grip, floats, weight and grounding cable) fit neatly inside the same box, reducing the possibility of misplaced pieces. Once carried to the installation site and assembled, the RU Flex 2100 DLS is easily carried on the shoulder and installed in a tank by one person. A weight, sized based on the length of the sensor, attaches to the bottom of the hose before installation to ensure the sensor straightens out inside the tank and to prevent sensor movement from affecting measurement accuracy.

The RU Flex 2100 DLS delivers consistently accurate level and temperature measurements of different types of fluids in both hazardous and non-hazardous environments. With 3/16” accuracy (optional), this sensor is ready to meet stringent API Custody Transfer requirements. Multiple fluid densities and temperatures do not affect measurement. The RU Flex 2100 DLS is suitable for production monitoring, inventory control, and leak detection in a variety of different types of storage tanks (crude oil, diesel, kerosene, gasoline, water and chemical). Communications to SCADA systems can be digital or analog and the DLS works with most wireless systems using Modbus RTU protocols and ASCII.

Hose Material and Length Pressure: UHMW-PE (Ultra High Molecular Weight Polyethylene)

Measurement lengths: 2 to 48 feet

Level Measurement Increments:

  • 1/8-in. resolution; 3/16-in. accuracy
  • 1/4-in. resolution; +/- 1/8-in. accuracy
  • 1/2-in. resolution; +/- 1/4-in. accuracy
  • +/- 0.1% repeatability

Coiled Diameter: Approximately 36-inch diameter (will vary slightly with the length of the sensor)


  • NYTROPHYL stainless steel
  • Two piece floats for field installation and replacement
  • One float used for product level
  • One float for water interface level
  • Designed to fit through a three-inch NFPT tank port

Operating Temperature Range: -40 degrees C to 80 degrees C

Temperature Measurement:

  • 12 inches from bottom
  • +/- 1.5 degrees C accuracy
  • Up to 8 distinct temperature measurements (one standard)

Power Requirements: • 5.6 VDC to 12.9 VDC

Power Consumption: 15 mA nominal 20 mA maximum

Pressure: 40 psi: standard


  • Modbus RTU 16-bit unsigned integer
  • Modbus RTU 32-bit floating point
  • Modbus RTU 2 x 16-bit
  • Serial Data via ASCII

Anchor Weight: 3 in. diameter, required weight varies based on sensor length

Wiring: 18 AWG recommended for digital circuits


Class I, Div. 1, Group D hazardous locations (when connected to an approved intrinsically safe barrier device)


  • ANSI/UL-913, 7th Edition
  • CAN/CSA C22, No. 157


Open communication protocols allow Electrolab’s RU Flex 2100 DLS to interface with most manufacturers’ equipment. We offer:

  • RS485
  • Two- or four- wire communications
  • Baud rate and parity programmable
  • 4-20mA signal available when connected to an Electrolab 3010 digital-to-analog converter board
  • Wireless compatibility with preferred partners