Sequence Program Description Method - Mitsubishi MELSEC QS Series User Manual

3
SEQUENCE PROGRAM EXECUTION

3.1.1 Sequence program description method

3
- 3 3.1 Sequence Program
3.1.1 Sequence program description method
The sequence program is created with the ladder mode of GX Developer.
The ladder mode is based on the concept of a sequence circuit of relay control. It
enables programming in representation close to a sequence circuit.
In the ladder mode, programming is performed in ladder block units.
A ladder block is the minimum unit for performing sequence program operation, which
starts from the left side vertical bus bar and ends at the right side vertical bus bar.
Left side vertical bus bar N/O contact N/C contact
X100
0
X101 X102
Step number
2
X104 X105
8
Y124
X100 to 105 indicate inputs.
Y120 to 124 indicates outputs.
Coil (output)
X103
Diagram 3.3 Ladder mode
Right side
Y120
vertical bus bar
Y121
Y122 Ladder block
Y123
Y124