Siemens Simatic S7-300 - Representation of the Analog Values of Analog Input Channels

Representation of the analog values of analog modules
5.1 Representation of the analog values of analog input channels
S7-300 Automation System Module data
5-2 Manual, 08/2006, A5E00105505-04
Example
The example below demonstrates the zero padding of unused bit positions for low resolution
values.
Table 5-1 Example: Bit pattern of a 16-bit and 13-bit analog value
Resolution Analog value
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
16-bit analog value 0 1 0 0 0 1 1 0 0 1 1 1 0 0 1 1
13-bit analog value 0 1 0 0 0 1 1 0 0 1 1 1 0 0 0 0
5.1 5.1 Representation of the analog values of analog input channels
Measured value resolution
The resolution of the analog values may differ, based on the analog module and module
parameters. At resolutions < 15 bits, all bits identified by "x" are set to "0".
Note
This resolution does not apply to temperature values. Converted temperature values are the
result of a conversion in the analog module.
Table 5-2 Supported analog value resolutions
Resolution
in bits (+ sign)
Units Analog value
dec hex high byte low byte
8 128 80
H
Sign 0 0 0 0 0 0 0 1 x x x x x x x
9 64 40
H
Sign 0 0 0 0 0 0 0 0 1 x x x x x x
10 32 20
H
Sign 0 0 0 0 0 0 0 0 0 1 x x x x x
11 16 10
H
Sign 0 0 0 0 0 0 0 0 0 0 1 x x x x
12 8 8
H
Sign 0 0 0 0 0 0 0 0 0 0 0 1 x x x
13 4 4
H
Sign 0 0 0 0 0 0 0 0 0 0 0 0 1 x x
14 2 2
H
Sign 0 0 0 0 0 0 0 0 0 0 0 0 0 1 x
15 1 1
H
Sign 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1