Handling

The sensors are switched on and off externally by using a magnet; see Figure bottom left. This allowed for a sensor design with a completely closed case. For switching the sensor on or off, a magnet has to be moved into the vicinity of the LED. The respective part of the sensor case is marked by a small cutout at the upper edge.

The sensors are recharged contactless by electromagnetic induction; no direct electrical connection is required. For recharging, the sensors have to be placed on the battery charging pad; see Figure bottom right.

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Before a particular sensor can be used, the transducer and the measurement tip have to be filled with degased and deionized water. The water filling ensures the hydraulic connection between the internal pressure transducer and the pore water in the cementitious material. The filling procecure consists of two steps:

  1. Filling the pressure transducer; see Figure bottom left.
  2. Filling the measurement tip, see Figure bottom right.
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Then, the sensor may be applied by vertically inserting it into the concrete surface; see Figure below.

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The wireless capillary pressure sensors are sending the measured data to the base station via radio transmission; see Figure bottom left. Subsequently, the data is recorded and displayed in real time by using a computer and appropriate software; see Figure bottom right.

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