22
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
1 Introduction
1.1 Programming Language in PLCs
1.
Introduction
This chapter explains basic items related to programming in FX
3U
and FX
3UC
programmable controllers
(PLCs).
1.1
Programming Language in PLCs
This section explains the features of programming in FX
3U
and FX
3UC
PLCs.
1.1.1
Types of programming languages
FX
3U
and FX
3UC
PLCs support the following three types of programming languages:
1. List programming
This method is the basis of programs.
1) Features
In this method, sequence instructions are input in the form of instruction words such as "LD", "AND" and
"OUT".
This input method is the basis of sequence programs.
2) Example of list display
2. Circuit programming
In this method, ladder formats are drawn on the graphic screen.
1) Features
In a circuit program, a sequence circuit is drawn on the graphic screen by sequence formats and device
numbers. Because a sequence circuit is expressed with contact symbols and coil symbols, the contents
of a program can be understood easily.
In the circuit display status, the PLC operations can be monitored.
2) Example of circuit display
3. SFC (STL <step ladder>) programming
This input method allows sequence design in accordance with the flow of machine operations.
1) Features
In an SFC (sequential function chart) program, sequences can be designed in accordance with the flow of
machine operations.
2) Compatibility between SFC programs and other programs
SFC programs can be converted into another program format. And when list programs and circuit
programs are created according to certain rules, they can be converted inversely into SFC programs.
Step
Instruction
Device number
0000
LD
X000
0001
OR
Y005
0002
ANI
X002
0003
OUT
Y005
…
…
…
X000
Y005
X002
Y005
The above list program is expressed in
the circuit diagram.
Содержание FX3U Series
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