Mitsubishi Electric FX3U SERIES - Cautions on Creation of Fundamental Programs; Programming Procedure and Execution Order

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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
6 What to Understand before Programming
6.2 Cautions on Creation of Fundamental Programs
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.
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.
(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