Temperature sensors are used to monitor the heat of hydration in mass concrete structures. They can also be used to monitor migration of ground water or seepage.
- Vibrating wire temperature sensors offer high accuracy and are convenient when other types of VW sensors are used.
- Resistance temperature sensors (RTDs or Thermistors) are a less precise, but economical alternative to the vibrating wire sensor.
The VW temperature sensor consists of a stainless steel body, a wire held in tension within the body, an electromagnetic coil, and signal cable. The body of the sensor expands and contracts with changes in temperature, increasing or decreasing the tension of the wire inside the body. When a readout is connected to the sensor, it sends an electric pulse to coil, which plucks the wire and causes it to vibrate at its natural frequency. A second coil picks up the vibration and returns a frequency to the readout. The frequency reading is converted to units of temperature by applying calibration factors.
The resistance temperature sensor consists of a stainless steel body, an RTD or thermistor inside the body, and a signal cable. The resistance of the RTD or thermistor varies with temperature. Resistance temperature sensors can be read with standard VW readouts, which have built-in conversion factors to convert the resistance reading to units of temperature.
- High Accuracy: The VW temperature sensor has an accuracy better than ± 0.3°C. Resistance temperature sensors offer an accuracy of ± 0.5°C.
- VW Compatible: The VW temperature sensor is especially convenient when there are other VW sensors at the site.
- Manual or Automatic Readings: Both types of temperaure sensor can be read manually using the VW Data Recorder or automatically using a data logger. Data logger connections for resistance sensors are different from those for VW sensors.
- Reliable Signal Transmission: The strong VW signal can be transmitted reliably over long distances with properly shield cable.
For more information
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