(2) Temperature difference between the terminals of the connection leads. (1) Poor lead material, contamination, moisture, (b) Insulation resistance at 500 ☌ (930 ☏) must be greater or equal to 2M Ωĭeviations of the temperature indication from the values in the table (parasitic and galvanic EMFs) (a) Insulation resistance at 20 ☌ (68 ☏) must be greater or equal to 100M Ω Minimum recommendations for insulation resistance according to IEC60751 are: (1) Insulation resistance of approximately 0.1M Ω in parallel with 100 Ω gives an error of the same magnitude as Tolerance Class B RTD sensors. Temperature indication error increases with increasing temperature (indication too low)ĭecreasing insulation resistance, acts as a shunt path for measured signal (2) Convert to a 4-wire circuit - in this case connection lead resistance effects completely eliminated. (1) Convert to 3-wire circuit, which will essentially eliminate the ambient temperature effects RTD sensor in 2-wire circuit the connection lead are subjected to a large temperature change. Temperature indication changes with changing ambient temperature Use a smaller measuring current(1mA current recommended) Self heating by measuring current too high Temperature indication generally too high To help resolve these problems, the table below shows a list of the common problems encountered in RTD applications and possible remedies or corrective measures. In using them, different types of application problems occur once in a while. Resistance Temperature Detectors(RTDs) are widely used across several industries – power, food and beverage etc – for temperature measurement.
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