1. What is the temperature measurement on Rheonics Sensor?
A temperature sensor is an instrument used to measure process temperature. It works by detecting changes in the temperature of its environment and transmitting this information back to the sensor electronics. Temperature sensors are used in many industries and applications, ranging from food processing and manufacturing to aerospace and power generation.
Rheonics viscosity and density meters SRV, SRD, DVP, and DVM provide accurate and reliable readings of various materials, including liquids, slurries, and solids. To ensure the accuracy of a Rheonics meter, calibration is necessary to ensure that the viscosity, density, and temperature readings are as precise as possible.
2. What is temperature calibration?
Calibrating a temperature sensor is a way of ensuring that temperature readings from the sensor are accurate and trustworthy. Temperature sensors are typically calibrated in a water bath at a known temperature. After that, you adjust the calibration values on the sensor until it accurately matches the temperature reading from the water bath or dry wells.
3. Calibration reference standard
A reference standard is a physical object that represents the quantity of interest in such a way that it can be used as a unit of measurement. In this support article, the measurement parameter is temperature. Examples of these instruments that could be used as a reference standard could be a water bath, dry wells, temperature simulators, or another calibrated instrument.
4. Calibration Methods
4.1. Calibrating with a water bath
The temperature calibration bath is a calibrator that is enclosed by a uniform fluid and is capable of adjusting the temperature for the test points. Temperature sensors of different sizes and shapes can be calibrated with their large volume and flexibility.
This method involves calibrating the Rheonics sensor against the temperature set in the water bath or dry well. It is imperative to wait for the sensor to stabilize, this is when the sensor's temperature output starts to vary by less than 0.1°C, this can take between 30 and 60 minutes unless you use an oven or STCM (Stabilization time is often quite long for high viscosity fluids or low thermal conductivity fluids).
Tests are performed against a reference gauge to calibrate a probe under test. The following steps are the most commonly used in calibration.
Open the RCP software and check the temperature that is shown in the measurement tab. For checking temperature outputs over 4-20mA channels, go to the service tab and verify that the output from channel 3-Temperature matches the expected value based on the temperature and the scaling limits.
Insert the Rheonics sensor inside the water bath, the immersion depth is going to affect the accuracy of the readings. Technicians often recommend following these rules:
1. 1% accuracy - immerse 5 diameters + length of the sensing element
2. 0.01% accuracy - immerse 10 diameters + length of the sensing element
3. 0.0001% accuracy - immerse 15 diameters + length of the sensing element
Wait for the sensor to stabilize, this is when the sensor's temperature output starts to vary by less than 0.1°C, this can take between 30 and 60 minutes.
In order to verify that the sensor is linear, you need to pick enough calibration points. It is usually sufficient to calibrate three to five points throughout the range. Remember to always calibrate in the temperature range.
4.2. External calibration probe
To calibrate using an external calibration probe instead of the internal probe from the water bath, it is important to verify that the reference probe has a traceable certificate(NIST traceable certificate or equivalent). The steps for calibration are the same as above but at the moment of inserting the Rheonics sensor in the water bath follow these recommendations:
Allow sufficient time for the probes to settle and for the bath temperature to stabilize after inserting the probes to be calibrated.
It is important to insert the probes at the same depth in the bath liquid. It is recommended for immersion depth to reduce the stem effect to a minimum: 20 x the diameter of the unit under test + the sensor length.
It is not recommended to submerge probe handles or Rheonics sensor cable (M12 connector) in water.
Reference probes and calibrators need to be themselves calibrated and should have a calibration certificate.
5. What can cause the difference between the calibration bath, reference probe, and a Rheonics sensor?
Figure 6. The temperature difference between the borings. 
Pictures, photos and images used are for illustration purposes and do not constitute any warranty or assertions on the suitability of use and should not be construed as an explicit or implicit recommendation or endorsement. All illustrations are given proper credit from our source of access and by their use here we do not specify or establish any copyright which belongs and stays unaffected with the existing copyright holder of that material