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Controlling
7.1 Overview
Control System Analysis
The static response (gain) and dynamic properties (lag, dead time, integration constant etc.)
of the controlling system are a decisive factor for the layout and design of the controller and
for the dimensions of its static (P action) and dynamic (I and D action) parameters.
Precise knowledge about the type and characteristics of the controlling system is therefore
imperative.
The optional software package "PID Self Tuner" is available to facilitate control optimization.
Controller Selection
The properties of controlling systems are given by technical process/machine circumstances
and can hardly be influenced. Therefore, to achieve good controlling results and to adapt it to
the recovery behavior of the system you must select the most suitable type of system
controller.
Creating the Controls
You can create the controls, ranging from the structure and parameter assignment to the
time-oriented call by the system program, widely without programming effort. However,
STEP 7 know-how is required.
Online Help
The STEP 7 Online Help also offers you information on the respective SFBs.
Additional Information
The integrated control is part of the standard control. For additional information on the topic
'standard controls' refer to:
● "Standard PID Control": SIMATIC S7 Manual and configuration package with ready-touse controller structures and comfortable parameter assignment screens.
● "Modular PID Control": SIMATIC S7 Manual and configuration package including a
flexible controller kit that is also suitable for complex tasks.
● "Controlling with SIMATIC", by Jürgen Müller: Practical manual for controlling with
SIMATIC S7 and SIMATIC PCS7
● "PID Self Tuner". SIMATIC S7 Manual and software package for Online self-optimization
of PID controllers
● FM 355/FM 455 is a self-sufficient back-up controller module that does not impose a load
on the CPU.
CPU 31xC: Technological functions
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Operating Instructions, 03/2011, A5E00105484-05