Working And Testing of RTD Sensor | PT100 | Resistance Temperature Detector | Electrical Technician
What is an RTD?
RTD stands for Resistance Temperature Detector. RTDs are sometimes referred to generally as resistance thermometers.
How do RTDs work?
RTDs work on a basic correlation between metals and temperature. As the temperature of a metal increases, the metal's resistance to the flow of electricity increases. Likewise, as the temperature of the RTD resistance element increases, the electrical resistance, measured in ohms (Ω), increases. RTD elements are commonly specified according to their resistance in ohms at zero degrees Celsius. The most common RTD specification is 100 Ω, which means that at zero degrees Celsius the RTD element should demonstrate 100 Ω of resistance.
How to Test a Resistance Temperature Detector
Resistance Temperature Detectors, or RTDs, work by measuring the resistance of the metal the detector is constructed from at various temperatures. Metals have different resistivities, and metals with higher resistivities work best in RTDs. For this reason platinum is widely used in RTDs, as platinum has a high resistivity. The resistivity increases with temperature, so RTDs in freezing temperatures would show a lower resistivity than RTDs in boiling temperatures with room temperature resistivity being a mid-range number.
Set your multimeter in resistance mode. Check the readings across the terminals of the RTD. At room temperature the reading should be around 110 ohms. The reading may vary depending on the metal in the RTD.
Place the RTD in ice water. Give it a couple of minutes to adjust and check the readings. You should get a lower number than the room temperature reading, around 100 ohms.
Give the RTD time to adjust to room temperature after removing it from the ice water. Place the RTD in boiling water and check the readings again. The number should be higher than the room temperature reading if your RTD is functioning properly.
Working And Testing of RTD Sensor | PT100 | Resistance Temperature Detector | Electrical Technician
What is an RTD?
RTD stands for Resistance Temperature Detector. RTDs are sometimes referred to generally as resistance thermometers.
How do RTDs work?
RTDs work on a basic correlation between metals and temperature. As the temperature of a metal increases, the metal's resistance to the flow of electricity increases. Likewise, as the temperature of the RTD resistance element increases, the electrical resistance, measured in ohms (Ω), increases. RTD elements are commonly specified according to their resistance in ohms at zero degrees Celsius. The most common RTD specification is 100 Ω, which means that at zero degrees Celsius the RTD element should demonstrate 100 Ω of resistance.
How to Test a Resistance Temperature Detector
Resistance Temperature Detectors, or RTDs, work by measuring the resistance of the metal the detector is constructed from at various temperatures. Metals have different resistivities, and metals with higher resistivities work best in RTDs. For this reason platinum is widely used in RTDs, as platinum has a high resistivity. The resistivity increases with temperature, so RTDs in freezing temperatures would show a lower resistivity than RTDs in boiling temperatures with room temperature resistivity being a mid-range number.
Set your multimeter in resistance mode. Check the readings across the terminals of the RTD. At room temperature the reading should be around 110 ohms. The reading may vary depending on the metal in the RTD.
Place the RTD in ice water. Give it a couple of minutes to adjust and check the readings. You should get a lower number than the room temperature reading, around 100 ohms.
Give the RTD time to adjust to room temperature after removing it from the ice water. Place the RTD in boiling water and check the readings again. The number should be higher than the room temperature reading if your RTD is functioning properly.
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