Guided Wave Radar (GWR) Level Sender

The 9400 series guided wave radar level transmitter is a breakthrough in cost effective very high accuracy, very high resolution liquid level sensing for heavy duty applications. Rochester Sensors’ GWR level sensor is the culmination of years of research into micropower impulse radar, time domain reflectometry and equivalent time sampling. Rochester Sensors Model 9400 liquid level sensor is used to monitor liquids such as fuels, chemicals, water, coolant, lubricants and other materials. The device is capable of maintaining very accurate level readings regardless of liquid. The 9400 can optionally be configured to accurately measure both fuel level and the level of dissimilar materials, such as water/fuel interface. The device emits a series of electromagnetic pulses down the sensor probe. Liquid/air interface, and dissimilar liquid interfaces provide a change in the characteristic impedance of the sensor probe, and create a reflection of the pulse. The time-of-flight of the reflected pulses is measured, and the liquid and interface levels are calculated.

  • Commercial vehicles and buses
  • Construction and mining machinery
  • Agricultural machinery
  • Mobile and stationary power generators, pumps and compressors

As depicted in the chart below, the Model 9400 has many advantages that other technologies do not and has a similar cost to ultrasonic or capacitive solutions but much cheaper than a typical guided wave radar product for process control applications.

9400 Introduction
Data Sheet

General Specifications

Active Sensing Range
15mm to 1000mm from flange
Housing Size
45mm (Height) x 67mm (diameter)
Configurable depending on output requirement
Operating and Storage Temperature Range
-40ºC to +105ºC
Water and Dust Sealing
Maximum Tank Pressure
15 PSI
ISO 16750-3
BS EN 60068-2-64: 1993 IEC 60068-2
Up to 500mm
ISO 16750-3
Surface Resistance
ISO 16750-3
Chemical Resistance
ISO 16750-5
Corrosion Resistance
VDA 621-415, DIN EN ISO 16270-2, DIN EN ISO 9227
Corrosive Gas Resistance
DIN 50018

Electrical Specifications

Supply Voltage
9-36 Vdc or 5Vdc regulated
Supply Current
35mA average
Superimposed AC over DC
ISO 16750-2
Supply Voltage Drop
ISO 16750-2 Section 4.6
UN ECE R10 revision 5

Output Specifications

Output Protocol
Analog – Voltage, PWM; Digital – LIN, CAN; Optional
programmable alarm output
±2.0% of span max (including nonlinearity,
hysteresis, temperature effects).


Die Cast Low Copper Aluminum
Sensor Tube
Extruded Low Copper Aluminum
Wetted Materials
Low Copper Aluminum, Buna Nitrile (or Viton), FR-4
Mounting Configuration
SAE 5 Bolt
Configurable including 5 and 6 bolt SAE

* Materials and specifications are subject to change with out notice. Pressure ratings subject to change due to temperature and other environmental considerations.

Product Inquiry - 9400

    Revised 04/8/2019