
B–61863E/15
2. SEQUENCE PROGRAMPMC SEQUENCE PROGRAM
49
Ę : Can be used
: Cannot be used
PA1 PA3 SA1 SA2 SA3 SA5 SB SB2 SB3 SB4 SB5 SB6 SB7 SC SC3 SC4 NB NB2 NB6
Ę Ę Ę Ę Ę Ę Ę Ę Ę Ę Ę Ę Ę
With the conventional PMC, a ladder program is described sequentially.
By employing a ladder language that allows structured programming, the
following benefits are derived:
D A program can be understood and developed easily.
D A program error can be found easily.
D When an operation error occurs, the cause can be found easily.
Three major structured programming capabilities are supported.
(1) Subprogramming
A subprogram can consist of a ladder sequence as the processing unit.
D
D
D
Job A
DDD
f
FUNC
DDD
f
Job B
(2) Nesting
Ladder subprograms created in (1) above are combined to structure
a ladder sequence.
D
D
D
Job A Job A1 Job A11
Job B
Job A12
Job An
Main Program Sub Program1 Sub Program2
2.4
SEQUENCE
PROGRAM
STRUCTURING