B-63983EN/02 4.LADDER LANGUAGE
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4.2 FUNCTIONAL INSTRUCTIONS
When creating a sequence program, you may find it difficult to code
certain types of functions with the basic instructions alone that
perform a one-bit logical operation each. One example is a shortcut
control function for a rotating part that involves numeric and other
complex operations. To facilitate the programming of these functions
that are difficult to code with the basic instructions alone, a set of
functional instructions are available.
This section describes how to use each functional instruction. For a
list of the functional instructions and information about their
specifications, see Subsection 2.1.6.
4.2.1 Format of the Functional Instructions
Before detailed descriptions of the individual functional instructions
are given, this subsection explains the format of the functional
instructions and their general specifications. Be sure to read this
subsection because it contains important information such as the rules
regarding the use of the functional instructions.
(1) Format of the functional instructions
Since the functional instructions cannot be represented using
relay symbols, they need to be represented in the format shown
in Fig. 4.2.1 (a). The structure of a functional instruction
consists of control conditions, an instruction, parameters, an
output coil (W1), a functional instruction operation result register
(R9000 to R9005).