Overview; What Is The St Language - Mitsubishi Electric MELSEC Q Series Programming Manual

1 OVERVIEW

1 OVERVIEW
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1.1 What Is the ST Language?

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The ST language is defined in the International Standard IEC61131-3 that stipulates
the logic description system in open controllers.
The ST language supports operators, control syntaxes and functions to permit the
following descriptions.
Control syntaxes such as conditional statement-dependent selective branch and
repeated statement-based repetition
Expressions using operators (*, /, +, -, <, >, =, etc.)
Call of user-defined function blocks (FB)
Call of functions (MELSEC functions, IEC functions)
Description of comments
The main features of the ST language are as described below.
(1) Free description in text format
The ST language is described in text format of alphanumeric characters, comments
and labels.
(2) Programming on the same level as those of the C and other high-level languages
Like the high-level languages such as C, the ST language can describe control with
control syntaxes such as conditional statement-dependent selective branches and
repeated statement-based repetitions. Hence, easy-to-read programs can be
written briefly.
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