M-Sens 2 – Online humidity measurement

The microwave sensor for continuous humidity measurement
in dry bulk solids

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

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

What do you want to do?


The M-Sens 2 is used for the continuous measurement of humidity on solids 
of all kinds.

The M-Sens 2 sensor can ideally be used, for example in container outlets, conveyor belts, conveyor screws, mixers and conveyor dryers.

It is important that the measuring surface of the sensor is always covered with material. The M-Sens 2 is a contact-measuring procedure. The ceramic disc (measuring surface) must always be covered with material.





The M-Sens 2-sensor works with precise high-frequency measurements and direct digitalisation of the measurement values and thus a high resolution.

Since the surface and capillary humidity of a material has a strong influence on its dielectric constant, the humidity can be determined exactly given a constant medium bulk density. By way of support, any fluctuations of the measuring value caused by the bulk density are balanced through an internal filter function. Temperature-related fluctuations of the measuring value are automatically compensated by the sensor. The calibration of the system can easily be carried out by the operator. On the installed system, the calibration is a matter of pushing a button and entering the humidity reference value.


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 probeshould 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 Examples

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

Online humidity measurement
of wood chips in the silo

Humidity measurement of fly ash

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

Online humidity measurement
of titanium oxide in a conveyor screw

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

Online humidity measurement 
of coal underneath a conveyor screw

Humidity measurement of brown coal

Global Technology Systems

P.O. Box 799 Shalimar, FL 32579. USA
(850) 651-3388
[email protected]


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