Siemens SIMATIC ET 200S - Compensation by resistance thermometer on the 2 AI RTD

Analog Electronic Modules
12-23
ET 200S Distributed I/O System
EWA-4NEB 780602402-12
Compensation by resistance thermometer on the 2AI RTD
If thermocouples connected to the inputs of the 2 AI TC have the same reference
junction, compensate using a 2AI RTD.
You can selected ”R TD” or ”none” as reference junction for the two channels of the
2AI TC module. If you select ”RTD”, the same reference junction (RTD channel) is
always used for both channels.
I
C+
M--
M+:
I
C--
M--
M+:
2
3
4
6
7
8
1
5
2
3
4
6
7
8
1
5
2AI RTD
2AI TC
Abbreviations used:
M+: Measuring cable positive
M--: Measuring cable negative
I
C+
Constant current cable positive
I
C--
: Constant current cable
negative
Insulated
thermocouples with
external compensation
by means of resistive
thermometer,
connected to 2AI RTD
(channel 0)
2AI RTD configured for
measuring range Pt100 climate
range
Figure 12-3 Compensation by 2AI RTD