Chapter 5 Ladder Diagram; Configuration; Ladder Symbols - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

5
LADDER DIAGRAM
RnPCPU
RnCPU RnENCPU
(Process)
Ladder diagram is a programming language used to describe sequence control. Each ladder consists of contacts and coils
and represents logical operations consisting of AND/OR in combinations of series and parallel.
This chapter describes the operation and specifications of the ladder diagram. For the operation method of the
engineering tool for creating a ladder program, refer to the following.
 GX Works3 Operating Manual
5.1

Configuration

The following are the programs written in ladder diagram.
(1) Ladder program consisting of a contact and a coil
(2) Ladder program configured in series
(3) Ladder program configured in parallel
(4) Ladder program using an instruction
(5) Ladder program using a standard function/function block

Ladder symbols

The following table lists the ladder symbols that can be used for programming in ladder diagram.
Item
Normally open contact
Normally closed contact
Rising edge pulse
Falling edge pulse
Negated rising edge pulse
Negated falling edge pulse
5 LADDER DIAGRAM
54
5.1 Configuration
RnPCPU RnSFCPU RnSFCPU
(Redundant) (Standard) (Safety)
Description
Energized when the specified device or label is on.
Energized when the specified device or label is off.
Energized on the rising edge (off to on) of the specified device or label.
Energized on the falling edge (on to off) of the specified device or label.
Energized when the specified device or label is off, on, or on the falling edge (on to off).
Energized when the specified device or label is off, on, or on the rising edge (off to on).
(1)
(2)
(3)
(4)
(5)