M-Sens 2 - Online moisture measurement

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M-Sens 2 -
Online moisture measurement

The microwave sensor for continuous moisture measurement
in dry bulk solids

Simple retrofitting for measurement in container outlets, conveyor screws, on conveyor belts, slides etc.

  • Moisture ranges 0 ... 65 % (depending on material)
  • Measurement accuracy 0.1 %
  • Online moisture measurement
  • Independent of the material colour
  • Temperature-resistant up to 120 °C
  • ATEX-certified
  • Recording of surface moisture and capillary moisture


M-Sens 2 is especially designed for continuous moisture measurement of solids during batching. This includes aswell discontinuous measurement.
M-Sens 2 is used for online moisture measurement of:
• all types of dust, powder, granulates and other bulk solids
• in different mounting positions

M-Sens 2 is characterized by its uncomplicated installation as well as by its simple calibration. Due to its hygrostability and its resistance to mechanical shocks and abrasion the entire sensor is very fail-safe and allows a long service life. The sensor window is protected by a ceramic disc being very resilient with regard to abrasion and pressure.


The M-Sens 2 sensor functionality is based on precise high-frequency measurement and direct digitalization of measured values, where from results a high resolution.
As the materials surface and capillary moisture influences strongly its specific conductive capacity, the moisture can be measured exactly by a constant averaged bulk density.
The calibration can be done very simply by the operator by pressing the button and entering the referenced moisture contents. In this context it is convenient that measured value fluctuations by bulk density variations are balanced by an internal filter function. Additionally, measured value fluctuations by temperature variations are compensated automatically by the sensor.

Mounting and Installation

Flexible positioning
The M-Sens 2 was developed to offer maximum flexibility during assembly. The following aspects should be taken into account in the positioning of the probe: The measuring field penetrates the densest materials (e. g. sand). With a minimum depth of 120 mm, the probe should always be directed at the material to avoid reflection problems. 
Installation situations

For a simple installation, a standard connection flange is available.  

Conveyor belt

Measurement of material moisture on a conveyor belt.
A constant material height is generated by attaching a material skimmer. This offers ideal conditions for an online measurement.

The installation in the lower third of a conveyor screw has the advantage that the material volume that passes over the sensor is almost constant, allowing for an optimal measurement. The movement of the auger flights is hidden.


Free fall pipe

To be able to measure in free fall pipes or inclined pipes (chutes) with the M-Sens 2, it is possible to gather material in front of the probe in the short term, for the duration the measurement, with a catching mechanism. After the measurement, the flap will open again and allows the gathered material to continue to drop. The measuring process can be permanently repeated in short or long intervals according to requirements.    

Technical Data

Sensor Housing Stainless steel 1.4571
  Sensor surface Ceramic
  Protection category IP 67 according to EN 60529
  Ex-protection (optional) Zone 20 (dust), zone 0 (gas)
  Material ambient temperature 0 ... + 120 °C
  Working pressure max. 10 bar
  Power consumption 0.6 W
  Weight approx. 1.0 kg
  Response time 0.1 seconds
  Measuring range 0... 65 % residual moisture (depending on material)
  Accuracy 0.1 % absolutely in the calibrated measuring range
  Connecting cable shielded cable 4-wired, 0.25 mm²
Transmitter Power supply 110/230 V AC (50 Hz) 24 V DC
  Power consumption 20 W / 24 V
  Current consumption max. 1 A at 24 V
  Protection category IP 65 according to EN 60529/10.91
  Operating temperature - 10... + 45 °C
  Dimensions 258 x 237 x 174 mm (W x H x D)
  Weight approx. 2.5 kg
  Interface RS 232, RS 485
  Cable glands 3x M16 (4.5-10 mm Ø)
  Cable cross section 0.2 - 2.5 mm² [AWG 24-14]
  Current output signal 1 x 4 ... 20 mA (0 ... 20 mA), load < 500 Ohm
  Switched output measuring alarm Relay with two-way contact max. 250 V AC, 1 A
  Digital inputs 2 inputs for active external control signals
  Data protection Flash

Application Form

Application examples

Click on a desired application example to navigate to a detailed description.


Online humidity measurement
of wood chips in the silo

Online humidity measurement
of coal underneath a conveyor screw

Online humidity measurement
of titanium oxide in a conveyor screw

Online humidity measurement
of fertiliser on a carriage on the conveyor belt

Online humidity measurement
of wood shavings on a carriage

Online humidity measurement
of potato powder on a slide

Online humidity measurement
of saw dust in a screw conveyor

Humidity measurement of fly ash

Humidity measurement of brown coal


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