Description of the algorithm

This page describes the graphical representation by the designer of object control algorithms with reference to the I/O table. This is necessary so that the programmer can implement the code of the programmable means of the automation object (controllers) as correctly as possible in accordance with the requirements of the designer. This document is a link between the designer and the programmer who implements the application software.

Control algorithms should cover the technology of the object as much as possible so that the PLC programmer and / or the visualization system programmer do not experience difficulties in reading the terms of reference.

The description of the algorithms must take into account all the states of the control objects, as well as all possible violations of the process equipment.

Below are the options for graphical representation by the designer of object control algorithms.

1. Function blocks.

This option is well suited for large facilities in the petrochemical industry and allows you to simultaneously determine on the same algorithm diagram information about the inputs and outputs associated with the algorithm, the output of information to the dispatcher (operator) and the algorithm itself.

2. Description in the form of a state machine

Autotuning

This representation is convenient for describing any relatively complex sequences. A prerequisite for such a presentation is the presence of state tables and transition conditions.

3. Description in the form of block diagrams

This approach to the description of algorithms is accepted all over the world and, despite a number of shortcomings (difficulty in binding to I / O tables), it is well suited for describing any sequences.

4. Combined 

 

This description is well suited for small systems, it is convenient and clear for maintenance personnel. You can quite quickly and quite specifically approve the list of conditions and the sequence of transitions.

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