Mitsubishi Q00JCPU User Manual page 69

3
SEQUENCE PROGRAM CONFIGURATION AND
EXECUTION CONDITIONS
(1) Sequence program description method
There are two different methods for describing sequence programs: ladder mode and
list mode.
(a) Ladder mode
(b) List mode
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
X0
0
X1 X2
Step number
2
X4 X5
8
Y24
X0 to 5 indicate inputs.
Y20 to 24 indicates outputs.
In the list mode, the contacts and coils indicated by symbols in the ladder mode
are programmed using dedicated instructions.
The following instructions are used for N/O contacts (a contact), N/C contacts (b
contact) and coils.
• N/O contact • • • LD,AND,OR
• N/C contact • • • LDI,ANI,ORI
• Coil • • • • • • • • OUT
Coil (output)
X3
Diagram 3.4 Ladder mode
3.1 Sequence Program
Right side
Y20
vertical bus bar
Y21
Y22 Ladder block
Y23
Y24
3
- 4
1
2
3
4
5
6
7
8