Siemens SIMATIC ET 200AL System Manual page 2121

Thermocouples
5.3 Compensation for the reference junction temperature
Connecting thermocouples and thermal resistors
The example below shows:
● An analog module with thermal resistor as reference temperature transmitter and
● Two analog modules with thermocouple as reference temperature receivers.
Connect the thermocouples to the supply lines at the reference junction, either directly or
with compensating lines. Wire the supply lines to the corresponding terminals of the module.
You may use cables made of any material to wire the thermal resistor to the module
terminals.
①
②
③
④
⑤
Figure 5-8
90
Thermocouple
Compensating line (same material as thermocouple)
Copper supply cable, for example
Thermal resistor (RTD)
Reference junction
Example: Connecting thermocouples/thermal resistors for group 0 compensation
Analog value processing
Function Manual, 06/2014, A5E03461439-AC