IEC 60751:2008 pdf free download

IEC 60751:2008 pdf free download
IEC 60751:2008 pdf free download.Industrial platinum resistance thermometers and platinum temperature sensors
6.5.4 Thermoelectric effect
The thermometer shall be heated to the declared maximum temperature with the thermometer terminals close to the ambient temperature. The immersion depth of the thermometer shall be varied until the EMF is at its maximum. Set the direct measuring current to the maximum permissible value and obtain resistance readings with the normal and reversed polarity of the current. The temperature equivalent of the difference between the resistance of the thermometer measured with the normal and reversed polarity of the current shall not exceed the tolerance value of the declared tolerance class.
6.5.5 Effect of temperature cycling
The thermometer shall be brought carefully to the upper limit of its temperature range and then exposed to air at room temperature. It shall next be brought slowly to the lower limit of its temperature range and then exposed to air at room temperature. At each limit, the thermometer shall be immersed to at least its declared minimum immersion depth and shall be maintained at the temperature for sufficient time to reach equilibrium. After 1 0 cycles between the upper and the lower temperature limits, the calibration at 0 °C shall not drift by more than the tolerance value at 0 °C for the respective tolerance class.
6.5.6 Effect of hysteresis
The resistance of the thermometer shall be measured in the middle of the temperature range after exposure to a temperature at the lower limit of the temperature range. Then the resistance should be measured again at the same temperature in the middle of the temperature range after exposure of the thermometer to a temperature at the upper limit of the temperature range. The difference between these two measurements shall not be larger than the calculated tolerance value at the test temperature for the respective tolerance class. It is important for both measurements that the thermometer goes directly from the ends of the temperature range to the temperature in the middle of range.