KEYENCE Visual KV Series - Manual (Page 54)

1.5 Extended Ladder Diagrams
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1
Chapter 1 Programming
2010
2010 2002
2010 0502
0501
0500 #01000
CMP
DM0000
LDA
#02000
CMP
#03000
CMP
2002 DM0000
LDA
#01000
CMP
2002
2010
#02000
CMP
0500
0501
2002
2010
#03000
CMP
2010 0502
In a conventional ladder diagram, operations
performed by the program cannot be easily
understood. In an extended ladder diagram,
operations performed by the program can be
understood at a glance.
When the start switch (0000) is set to ON, a lamp (0500) is lit and
timer 0 is activated.
0000 1100
T000
T001
0500
0501
0502 0000
1000
STG
1001
STG
#00030
T000
#00020
T001
1002
STG
1001
JMP
1002
JMP
ENDS
1100
DIFU 1000
SET
When timer 0 turns ON three seconds later, the lamp goes out, a
buzzer (0501) is sounded, and timer 1 is activated.
When timer 1 turns ON two seconds later, the buzzer is stopped
and the motor (0502) starts to rotate.
When the start switch (0000) is set to OFF, the motor is stopped
and all operations are reset.
0000
T002
T001
T000
1000
0500 0501
0501
0500
0500
0000
1000
T002
1001
T000
T001
T002
1001
0501
1002
T000
1002
T001
1003
1001
1003
1002
1003
#00010
T000
1000
DIFU
1001
STG
1001
JMP
1003
JMP
1002
JMP
#00030
T002
#00020
T001
#00010
T000
1000
DIFU
1002
STG
1003
STG
#00020
T001
1003
#00030
T002
1001
SET
By using an extended ladder diagram as shown
above, the program can be executed in the
sequence of the processing to be performed. So
even a person who uses a relay sequence for the
first time can understand the processing contents.
By combining the STG instruction, double coils
can also be used.
1.5.2 Advantages of Extended Ladder Diagrams
The number of lines in a ladder diagram can be reduced.
Because both output instructions and input instructions can be written side by side,
the number of program lines can be reduced.
As the result, the contents of the program can be seen at a glance.
Example
When DM0000 stores 1000, 0500 turns ON.
2000, 0501 turns ON.
3000, 0502 turns ON.
Conventional ladder diagram Extended ladder diagram
Processing sequence is clear.
Ladder symbols can be laid out in processing sequence, so the program flow is
easier to understand. In addition, maintainability is considerably improved.
Example
When the start switch is set to ON, a lamp is lit for three seconds, a buzzer is
sounded for two seconds, and then the motor starts to rotate.
Conventional ladder diagram Extended ladder diagram
KVNKA Chap 01P.p65 08.3.11, 11:49 AM 30