IEC 60751:2008 pdf free download – Industrial platinum resistance thermometers and platinum temperature sensors
3.2 insulation resistance
electrical resistance measured between any part of the electric circuit and the sheath atambient or elevated temperatures and with a specified measuring voltage (a.c or d.c)
3.3 minimum immersion depth
immersion depth at which the change from the calibration at full immersion does not exceed0.1°C
3.4 nominal resistance
expected resistance R of a resistor or resistance thermometer at 0 °C,declared by themanufacturer and shown in the thermometer marking,usually rounded to the nearest ohm.Platinum resistors are often characterized by their nominal: A Pt-100 resistor is a resistor withR= 100 o
3.5 platinum resistance thermometerPRT
temperature responsive device consisting of one or more sensing platinum resistors within aprotective sheath，internal connecting wires and external terminals to permit connection ofelectrical measurement instruments.Mounting means and connection heads may be included.Not included is any separable protection tube or thermowell
3.6 temperature sensitive length
length of the thermometer whose temperature directly influences the resistance measured.Usually the temperature sensitive length is related to the length of the resistor
3.7 platinum resistor
resistor made from a platinum wire or film with defined electrical characteristics, embedded inan insulator (in most cases glass or ceramic), designed to be assembled into a resistancethermometer or into an integrated circuit
3.8 self-heating
increase of the temperature of the resistor or of the resistor in a thermometer caused by thedissipated energy of the measuring current
3.9 self-heating coefficient
coefficient with the dimension °C/mW is characteristic for a resistor/thermometer anddescribes the temperature increase of the resistor per unit power dissipated.This coefficientis evaluated under specified operating conditions of the resistor or thermometer.The medium,its flow conditions and temperature should be specified
3.11 thermal response time
time a thermometer takes to respond at a specified percentage to a step change intemperature. To specify the response time，it is necessary to declare the percentage ofresponse,usually to.,9，To.5，or to.,1，which gives the time for 90 %，50 % or 10 % of theresponse.The test medium and its flow conditions have to be specified (usually flowing waterand/or flowing air)
3.12 thermoelectric effect
effect of inducing the electro-motive force (EMF) caused by different metals used in theelectric circuit of the thermometer and by thermoelectric inhomogeneity of the internal leadsat the conditions of temperature gradients along the leads.The induced EMF is measuredacross the terminals of the thermometer while the thermometer is subjected to a specifiedtemperature
4Characteristics
The temperature/resistance relationships and tolerances in this chapter are valid for thesensing resistors at its connecting points. For thermometers， they are ‘valid for the completethermometer at its terminals.
In the case of two-wire connections，the resistance values of the leads between theconnecting point of the resistor and the terminals shall be considered.They may be indicatedon the thermometer and shall be subtracted from measured resistances. ln some cases, italso may be advisable to consider the temperature coefficient of the lead wires, thegeometrical characteristics of the wires and the temperature distribution along their length.
4.2Resistance values
The temperature/resistance relationship in Table 1 is given for a resistor with nominalresistance of 100 Q.For other nominal resistances R, such as; 10 Q,500 Q or 1 000 2, thetable can be used by multiplying the table values with the factor R/100 2.