IMC CANSAS - Temperature Measurement; Thermocouples as Per DIN and IEC

210 Measurement Technique
imc CANSAS Users Manual - Doc. Version 1.9 - 05.12.2014© 2014 imc Meßsysteme GmbH
5.1.6 Temperature measurement
Two methods are available for measuring temperature.
Measurement using a Pt100 requires a constant current, e.g. of 250 µA to flow through the sensor. The
temperature-dependent resistance causes a voltage drop which is correlated to a temperature according
to a characteristic curve.
In measurement using thermocouples, the temperature is determined by means of the electrochemical
series of different alloys. The sensor produces a temperature-dependent potential difference from the
terminal in the CAN connector pod. To find the absolute temperature, the temperature of the terminal
point must be known. For the Pt1000 this is measured directly in the terminal pod, and therefore an
additional type of connector pod is needed.
The voltage coming from the sensor will be converted into the displayed temperature using the
characteristic curves according temperature table IPTS-68. An exception are the modules -CANSAS-T1
and -CANSAS-T4, where voltage coming from the sensor is converted according to the IEC584-1 / ITS90
standard. The temperature ranges of these modules differ from the temperature ranges of normal
CANSAS modules.
5.1.6.1 Thermocouples as per DIN and IEC
The following standards apply for the thermocouples, in terms of their thermoelectric voltage and
tolerances:
Thermocouple
Symbol
max. temp.
Defined up to
(+)
(-)
DIN IEC 584-1
Iron-constantan (Fe-CuNi)
J
750°C
1200°C
black
white
Copper-constantan (Cu-CuNi)
T
350°C
400°C
brown
white
Nickel-chromium-Nickel (NiCr-Ni)
K
1200°C
1370°C
green
white
Nickel-chromium-constantan (NiCr-CuNi)
E
900°C
1000°C
violet
white
Nicrosil-Nisil (NiCrSi-NiSi)
N
1200°C
1300°C
red
orange
Platinum-Rhodium-platinum (Pt10Rh-Pt)
S
1600°C
1540°C
orange
white
Platinum-Rhodium-platinum (Pt13Rh-Pt)
R
1600°C
1760°C
orange
white
Platinum-Rhodium-platinum (Pt30Rh-Pt6Rh)
B
1700°C
1820°C
n.a.
n.a.
DIN 43710
Iron-constantan (Fe-CuNi)
L
600°C
900°C
red
blue
Copper-constantan (Cu-CuNi)
U
900°C
600°C
red
brown
If the thermo-wires have no identifying markings, the following distinguishing characteristics can help:
Fe-CuNi: Plus-pole is magnetic
Cu-CuNi: Plus-pole is copper-colored
NiCr-Ni: Minus-pole is magnetic
PtRh-Pt: Minus-pole is softer
The color-coding of compensating leads is stipulated by DIN 43713. For components conforming to IEC
584: The plus-pole is the same color as the shell; the minus-pole is white.