Siemens SIMATIC S7-200 - Input Block Diagram for EM 231 and EM 235

S7-200 Specifications
A-45
S7-200 Programmable Controller System Manual
A5E00066097-02
Input Block Diagram for EM 231 and EM 235
Figure A-22 shows the EM 231 and EM 235 input block diagrams.
R
R
C
C
C
A+
RA
A-
Rloop
R
R
C
C
C
B+
RB
B-
Rloop
R
R
C
C
C
C+
RC
C-
Rloop
A=1
A=2
A=3
Buffer
+
-
Input filter MUX 4 to 1
BUFFER
DATA
011
A/D Converter
EM 235
A=4
R
R
C
C
C
D+
RD
D-
Rloop
GAIN ADJUST
Instrumentation
AMP
+
-
REF_VOLT
Offset Adjust
R
R
C
C
C
A+
RA
A-
Rloop
R
R
C
C
C
B+
RB
B-
Rloop
R
R
C
C
C
C+
RC
C-
Rloop
A=1
A=2
A=3
Input filter
MUX 4 to 1
BUFFER
011
A/D Converter
A=4
R
R
C
C
C
D+
RD
D-
Rloop
GAIN ADJUST
Instrumentation
AMP
+
-
EM 231
Figure A-22 EM 231 and EM 235 Input Block Diagram