Mitsubishi QCPU (Q Mode), Руководство пользователя

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MELSEC-Q
4 SEQUENCE PROGRAM CONFIGURATION AND EXECUTION
CONDITIONS
4
(2) Sequence program writing format
Programming for sequence programs is enabled using either ladder mode or list
mode.
(a) Ladder mode
• The ladder mode is based on the relay control sequence ladder.
Programming expressions are similar to the relay control sequence ladder.
• Relay symbolic language programming occurs in ladder block units.
A ladder block is the smallest unit of sequence program operation, with
the ladder beginning from the left bus and ending at the right bus.
Y21
Y22
Y23
Y24
X1
Y20
X2 X3
X4 X5
Y24
X0
0
2
8
Left bus
Step No.
Right bus
Ladder blocks
X0 to X5 : Indicate inputs.
Y20 to Y24 : Indicate outputs.
a contact b contact Coil (output)
Fig.4.1 Ladder Block
(b) List mode
The list mode uses dedicated instructions instead of the contact symbols,
coil symbols, etc., used in the ladder mode.
Contact a, contact b and coil instructions are as follows:
• a contact ............LD, AND, OR
• b contact ............LDI, ANI, ORI
• coil......................OUT
(3) Program operation
In sequence program, the instructions are executed in order beginning from step
0 and ending at the END/FEND.
With ladder mode, the instructions in a ladder block are executed in order
beginning from left bus to the right bus. When one ladder block is completed, the
next downward ladder block will be executed.
0 LD
1 AND
2 LD
3 AND
4 ORB
5 OR
6 AND
7 AND
8 AND
9 OUT
10 END
Top to
bottom
Number 1) to 11) indicate the operating
order of the sequence program.
[Ladder mode]
Left to right
1)
X0
2)
X1
7)
X5
8)
X6
9)
X7
3)
X2
4)
X3
6)
X4
10)
Y10 0
10
5)
11)
END
[List mode]
Executed in
order beginning
from step 0 to
the END
instruction.
Step No.
X0
X1
X2
X3
X4
X5
X6
X7
Y10
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
Fig.4.2 Sequence Program Operation