Float Level Sensors

Monitor liquid levels with a float level sensor and a ControlByWeb® module. Receive text/email alerts when a user-specified level is reached. Log and graph a tank’s level data over time.

  • MPX Float Sensor

    MPX Float Sensor

    Monitor liquid levels with a float level sensor and a ControlByWeb® module. Receive text/email alerts when a user-specified level is reached. Log and graph a tank’s level data over time.

    Max Length: Up to 32ft. (175.25m)

    Modbus RS-485

    4-20mA, 2-Wire

    External Power: 12-24 VDC

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  • X-412™ | 4‐Channel Relay & Analog Input Module

    The X-412™ is a powerful analog-to-digital Ethernet I/O PLC. It features 4 analog inputs, 4 relays, and a built-in web server for infinite control and monitoring possibilities.
    • 4 Relays
    • 4 Analog Inputs

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  • X-404 and X-404C with Cell Icon

    X-404™ | Modbus RS-485 Module

    The X-404™ is purpose-built to monitor up to 32 Modbus RS-485 devices and/or sensors. It also includes a 1-wire bus for temperature and humidity monitoring.

    The X-404C offers wireless capability with a built-in, low-power LTE-M cellular radio. Cellular models with an annual data plan include a dual SIM that provides combined coverage through AT&T and T-Mobile, automatically switching between the two for the best coverage.

    Modbus RS-485 input

    Up to 16 temperature sensors

    Cellular version available

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  • 24V DIN Rail Power Supply

    24V DIN Rail Power Supply

    The UNO POWER power supply unit impresses in worldwide use thanks to maximum energy efficiency. Low idling losses and the high degree of efficiency save energy. Thanks to its high power density, the UNO POWER power supply unit is the ideal solution, particularly in compact control boxes.

    Output: 24 V DC±1%, 1.75 Amp

    Input Voltage: 100-240V AC

    Input Frequency: 45-65 Hz

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  • 12VDC Power Supply

    Power Supply | 12VDC



    12V DC

    1.5Amp (100-240V AC Input)

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  • MND Modbus Display

    MND Modbus Display

    This user-friendly display is compatible with select ControlByWeb devices and does more than simply display its sensor’s readings. Features include the ability to alter sensor settings using the Modbus registry and to power a sensor with its batteries. Works on any Modbus network.

    Easy 3-button programming

    RS-485: 9600 baud (Modbus RTU)

    Local display for up to 10 sensors

    Display: 5 digit LCD, 0.4 in. digits

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Float Sensor – Liquid Level Switch

Monitor liquid levels with a float level sensor and a ControlByWeb® module. Receive text/email alerts when a user-specified level is reached. Log and graph a tank’s level data over time.

How do Float Sensors Work

Magnetostrictive liquid level sensors consist of a float that moves up and down a stem, or rod. The float contains a permanent magnet, and the stem houses a wire waveguide that creates a magnetic field, making it possible to detect the position of the float on the stem.

An electrical pulse travels down the waveguide, magnetizing it. When the pulse meets the magnetic field from the float, a vibration, also called a strain pulse, travels back to the sensor housing.

The Float sensor or liquid level switch then measures the difference in time between the initial pulse, and the strain pulse, giving it an accurate and continuous reading of the tank’s current level.

Liquid Types

Float Level Sensors work well with clean and dirty liquids, as they are customizable for almost any application.

Clean Liquid Icon
Dirty Liquid Icon
Corrosive Liquid Icon

Float Sensor Benefits

  • Easy to install.
  • Provide the most reliable and accurate method of level monitoring.

Sensor Ranges

  • MPX float sensors are customizable for monitoring up to 32 ft with multiple float sensors.

Sensor Accuracy

  • Sensors are accurate within 0.05% of their detected range.

Sensor Output

Modbus RS-485

Easily configure sensor data using the X-404 Modbus Master Controller. No voltage scaling is required!


For existing systems that require 4-20mA, connect the sensor to one of our compatible devices (X-418, X-420, X-22s).

Top of Tank

Carefully lower the MPX Float Sensor into the tank, then secure the sensor to the tank. If the floats don’t fit through the mounting hole, remove the floats and connect the floats from the inside of the tank after the stem has been lowered through the mounting hole.

MPX Sensor Install Example Diagram

Sensor Specifications

  • Max Length: Up to 32ft. (175.25m)
  • Accuracy: Greater of ±0.04 in. (±1mm)
    or 0.05% of full range
  • Resolution: Modbus ±0.04 in. (±1mm)
    4-20 mA: 14 bit DAC
  • Operating Temp: -40°F to 180°F (-40°C to 80°C)
  • Modbus RTU (RS-485) with Temperature output
  • 4-20mA, 2-Wire
  • Dual 4-20mA (Loop-Powered 3 wire)
  • External Power: 12-24 VDC
  • Protection Rating: NEMA 4X, IP65
  • Certifications: Class 1 Division 1 Groups C & D, Class 1 Zone 1, Class 1 Zone 2
  • NO CLOUD NEEDED! Remote connection available with ControlByWeb devices (see below)
  • Automatic programming via ControlByWeb device
  • Housing: Cast aluminium, epoxy coated
  • Cable Length: Customizable
  • Dual-Level: Monitor two liquid levels with a single sensor
  • Operating Temp: -40°C to 85°C
  • Top of tank | Simple to install and program
MPX Control Example Diagram

Remote Monitoring

Each float sensor can be connected to a ControlByWeb module to remotely monitor liquid levels in real-time using a standard web browser or mobile device. Liquid levels can be presented to the user as a simple liquid height measurement, or the module can be configured to calculate the volume of liquid used or the volume remaining in the tank and present that to the user. No special software required.

MPX Pump Control Example Diagram

Remote Control & Monitoring

In addition to simple remote monitoring, ControlByWeb modules are fully programmable and provide custom control capabilities as well. For example, you can connect a pump to a relay on a ControlByWeb module and remotely run the pump manually, or configure the pump to automatically run if the level gets too low.

Level Monitoring in Hazardous Environments

Warning: Use of these products to monitor tank levels of potentially explosive liquids or substances (such as gasoline), requires strict adherence to local safety laws and regulations. ControlByWeb modules (such as the X-404, X-420, etc) are NOT designed to be intrinsically safe and must be installed with both physical and electrical safety barriers. Installation should only be performed by qualified individuals and companies who understand the safety requirements. Please refer to sensor installation manuals and consult local safety regulations for more information.

Intrinsically Safe Modbus Monitoring Example Diagram
Intrinsically Safe 4-20mA Monitoring Example Diagram

Common Industries

Oil and Gas Image

Oil and Gas

The MPX can be custom ordered to be chemically resistant, making it optimal for monitoring oil and gasoline.

Mud Tanks Image

Mud Tanks

Oil drilling uses powerful pumps to move mud out of the way of the drill. The MPX’s sturdy design makes it ideal for the violent and turbulent conditions of a mud tank.

Low Cost Tank Monitoring Image

Tank Levels – Tank Farms

In any application, the MPX provides the most reliable and accurate method of level monitoring in tank batteries and tank farms.

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