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Analog Value Processing
Set the measuring range of the module to 500 mV and plug in a 6ES5 498-1AA 71 module.
The measuring range 4 to 20 mA is resolved into 2048 units from 512 to 2560. For representation
in the range 0 to 2048, 512 units must be subtracted at the software level.
Table 10-22. Representation of Digitized Measured Values of the 460 and 465 AI
(Current Measuring Range 4 to 20 mA)
I
Units
V
I
in mA
in mV
32.796
4096+OV
1024
31.992
4095
1023.76
24.0
3072
23.992
3071
20.008
2561
20.0
2560
16.0
2048
4.0
512
3.992
511
3.0
384
2.992
383
0.0
0
*
Short-circuit of the two-wire transducer
Note
The 31.25
shunt resistor integrated in the 498-1AA71 suppresses the wire break
signal (the F bit is not set). You can thus detect a wire break only by comparing the
measured value with a lower limiting value in the user program. A measured value
lower than, for example, 1 mA (=128 units) would then be interpreted as a wire break.
10-44
Digitized Measured Value
I
15 14 13 12 11 10
0
1
1
1
1
0
1
1
1
1
750.0
0
1
1
0
0
749.76
0
1
0
1
1
625.24
0
1
0
1
0
625.0
0
1
0
1
0
500.0
0
1
0
0
0
125.0
0
0
0
1
0
124.76
0
0
0
0
1
93.75
0
0
0
0
1
93.5
0
0
0
0
1
0.0
0
0
0
0
0
9
8
7
6
5
4
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
S5-115U Manual
T
F OV
Range
2
1
0
Overflow
0
0
1
0
0
0
Over-
range*
0
0
0
0
0
0
0
0
0
0
0
0
Nominal
range
0
0
0
0
0
0
0
0
0
Below
nominal
0
0
0
range
0
0
0
Wirebreak
0
0
0
EWA 4NEB 811 6130-02b
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