Mitsubishi Q00JCPU User Manual page 102

3
SEQUENCE PROGRAM CONFIGURATION AND
EXECUTION CONDITIONS
(1) Sequence program description method
3
- 4 3.1 Sequence Program
There are two different methods for describing sequence programs: ladder mode and
list mode.
(a) Ladder mode
The ladder mode is a mode based on the concept of a sequence circuit of relay
control.
In the ladder mode, programming close to the image of sequence figure is
possible.
Programming is performed in units of ladder blocks.
A ladder block is the minimum unit for operating sequence programs, 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
Step number
2
X4
8
Y24
X0 to 5 indicate inputs.
Y20 to 24 indicates outputs.
(b) List mode
When programming in the list mode, the symbols, such as contacts and coils,
used in the ladder mode are replaced with dedicated instructions.
The following instructions are used for normally open contacts, normally closed
contacts, and coils.
• Normally open contact LD,AND,OR
• Normally closed contact LDI,ANI,ORI
• Coil • • • • • • • • • OUT
X2 X3
X5
Figure 3.4 Ladder mode
Coil (output)
Right side
Y20
vertical bus bar
Y21
Y22 Ladder block
Y23
Y24