Mitsubishi Electronics FX3G User Manual
169
FX
3S
/FX
3G
/FX
3GC
/FX
3U
/FX
3UC
Series
Programming Manual - Basic & Applied Instruction Edition
6 What to Understand before Programming
6.2 Cautions on Creation of Fundamental Programs
1
Introdu
ction
2
Ov
ervi
ew
ew
3
Instruction
Li
st
4
D
evices
in Det
ai
l
5
Specifi
ed the
De
vice
&
C
onst
ant
ant
6
Bef
ore
ore
Pr
og
ra
mmi
ng
ng
7
Bas
ic
ic
Instruction
8
FN
C00-FN
C00-FN
C0
9
Program Fl
ow
9
FNC
10-FN
C19
Mov
e & Com
e & Com
pare
10
FNC
20-FNC
29
Arith. & Lo
gi
c
Operati
on
6.2
Cautions on Creation of Fundamental Programs
This section explains cautions on programming.
6.2.1
Programming procedure and execution order
1. Contact configuration and steps
Even for a sequence circuit offering the same operation, the program can be simplified and the number of steps can
be saved depending on the contact configuration method.
1) It is recommended to write a circuit with many serial contacts in an upper position.
be saved depending on the contact configuration method.
1) It is recommended to write a circuit with many serial contacts in an upper position.
2) It is recommended to write a circuit with many parallel contacts in a left position.
2. Program execution and programming order
A sequence program is executed "from top to bottom" and "from left to right".
Code the sequence instruction list according to this rule.
Code the sequence instruction list according to this rule.
(1)LD
(2)LD (3)AND
(5)OUT
(4)ORB
(1)LD
(3)OR
(2)AND
(4)OUT
ORB instruction is not necessary
(1)LD
(3)OR
(5)OUT
(4)ANB
(2)LD
(1)LD
(2)OR
(3)AND
(4)OUT
ANB instruction is not necessary
(3)
(1)
(2)
(4)
(7)
(5)
(6)
(8)
(9)
(10)
(11)
Executed