Process Moisture Measurement

For stationary applications in industrial processes the MOIST unit construction set has available different process moisture sensors. They all are highly integrated as "smart" moisture sensors and can realize some measurement functions also in standalone operation. In combination with the control unit MOIST CONTROL the signals of different moisture sensors can be combined and more complex measurement algorithms can be realized.

Depending on the desired moisture range, resolution, interaction volume or measuring depth several moisture sensors with different working principles can be used. Graded interaction volumes of the used microwave applicators allow a variation of the measuring volume from some cm³ to the range around 100 l.

The schedule shows the different types of sensing heads with their specifical properties. Depending on the special features of the moisture problem to be solved one or more sensors can be useful for this. The spectrum of possible applications is reaching from precision measurements in materials with low moisture contents over tasks in the middle moisture range to high moisture applications as for measurements in organic materials.

The schedule shows the different types of sensing heads with their specifical properties. Depending on the special features of the moisture problem to be solved one or more sensors can be useful for this.

As a standard the sensing heads have an analogous current loop interface (4 - 20 mA) for continous reading of measurements and a serial interface for programming. Additionally a serial interface RS485 is available. In addition other interfaces like CAN bus can be implemented.

Because of the high measurement speed the moisture measurement can be carried out in real time. T he minimum data acquisition time is 5 ms. This way moisture measurements in flowing materials with speeds < 1 m/s are no problem. For materials moving faster other solutions derived from the basic sensors versions can be found, which can be adapted to the special task.

Simple mathematical operations like averaging for smoothing of reading or special data processing routines can be realized customer and application specific in the moisture sensors themselves. For more complex measuring routines like windowing or calculation of validation parameters the control unit MOIST CONTROL is used.

¹  achievable accuracy is depending on the material, its consistency and the quality of the samples available for calibration
²  under the conditions dry material with ε_r = 4 and low moisture
³  an at well defined materials in the lower moisture range (< 10% wet base) under laboratory conditions, T = 23°C = const.