Theodor Friedrichs COMBILOG 1020, Hardware Manual

Page: 49 / 170

Hardware Manual COMBILOG 1020
49
If the temperature is measured by external cold junction compen-
sation, a second thermocouple of the same type is required,
which is connected in series with the first one. The polarity is se-
lected so that the thermoelectric voltages subtract each other.
The second thermocouple is set to a fixed reference temperature
ϑ
r
(mostly
ϑ
r
= 0°C). The datalogger then calculates the tempera-
ture at the measuring position by means of the linearization curve
as
ϑ
x
= Lin(U
x
+Lin
-1 ϑ
r
). The datalogger will be informed about the
reference temperature
ϑ
r
via the configuration software (“cold
junction temperature”).