5 LADDER DIAGRAM
5.1 Configuration
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5 LADDER DIAGRAM
Ladder diagram is a language that describes the sequence control by indicating logical operations consisting of "AND" or
"OR" with combinations of series connections and parallel connections in a ladder consisting of contacts and coils.
5.1 Configuration
With the ladder diagram, the following ladder can be created.
(1) A ladder consists of contacts and coils
(2) A ladder connected in series
(3) A ladder connected in parallel
(4) A ladder where instructions are used
(5) A ladder where standard functions and function blocks are used
Ladder symbols
This section shows ladder symbols that can be used for programming in the ladder diagram.
Element Symbol Description
NO contact Turns on when a specified device or label is ON.
NC contact Turns on when a specified device or label is OFF.
Rising edge Turns on at the rising edge (OFF to ON) of a specified device or label.
Falling edge Turns on at the falling edge (ON to OFF) of a specified device or label.
Negated rising edge Turns on when a specified device or label is OFF or ON, or at the falling edge (ON to OFF) of a
specified device or label.
Negated falling edge Turns on when a specified device or label is OFF or ON, or at the rising edge (OFF to ON) of a
specified device or label.
Conversion of operation result
to leading edge pulse
Turns on at the rising edge (OFF to ON) of an operation result. Turns off when the operation result
is other than the rising edge.
Conversion of operation result
to trailing edge pulse
Turns on at the falling edge (ON to OFF) of an operation result. Turns off when the operation result
is other than the falling edge.
Inverting the operation result Inverts the operation just before this instruction.
Coil Outputs an operation result to a specified device or a label.
Instruction Executes an instruction specified in [ ].
Turn-back Turns back a circuit by creating a turn source symbol and a turn destination symbol when the
number of contacts exceeds the number of contacts that can be created in one line.
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