Analog Value Representation; Introduction; Analog Value Representation For Measuring Range With Simatic S7 - Siemens 2AO U HF Manual

Analog value representation

4.1

Introduction

Electronic modules with analog outputs
With the electronic modules with analog outputs, digital values set by a controller can be
converted to a corresponding analog signal (current) in an analog output module and used to
control suitable actuators (setpoint input for speed controllers, temperature controllers and
similar).
4.2

Analog value representation for measuring range with SIMATIC S7

Analog value representation
With the same nominal range, the digitized analog value is the same for input and output
values. Analog values are represented in two's complement.
The following table shows the analog value representation of the analog electronic modules.
Table 4-1 Analog value representation (SIMATIC S7 format)
Resolution
Bit number
Significance of the bits
Sign
The sign (S) of the analog value is always in bit number 15:
● "0" → +
● "1" → –
2AO U HF analog electronic module (6ES7135-4LB02-0AB0)
Manual, 04/2007, A5E01076940-01
15 14 13 12
S 2 2 2
14 13 12
Analog value
11 10 9 8 7
2 2 2 2 2
11 10 9 8
6 5 4 3
2 2 2 2
7 6 5 4 3
4
2 1 0
2 2 2
2 1 0
15