Siemens SIMATIC S7-200 System Manual page 434

S7-200 Programmable Controller System Manual
Input filter
Figure A-18 Input Block Diagram for the EM231 Analog Input, 8 Inputs
A+
R
C
RA
C
C
Rloop
A--
R
B+
R
C
RB
C
Rloop C
B--
R
C+
R
C
RC
C
C
Rloop
C--
R
D+
R
C
RD
C
Rloop
C
D--
R
Input filter MUX 4 to 1
Figure A-19 Input Block Diagram for the EM 235
Output Data Word Format for EM 232 and EM 235
Figure A-20 shows where the 12-bit data value is placed within the analog output word of the
CPU.
420
EM 231 Analog Input, 8 Inputs
Instrumentation
AMP
MUX 8 to 1
EM 235
A=1
+
Instrumentation
AMP
--
A=2
REF_VOLT
+
Buffer
--
A=3
Offset Adjust
A=4
GAIN ADJUST
BUFFER
A/D Converter
GAIN ADJUST
BUFFER
A/D Converter
11
DATA
0