
10.STEP SEQUENCE FUNCTION B-63983EN/02
- 966 -
(9) Calling block
To execute a block as the main program in a step sequence, call
the block with the CALLU (SUB 66) or CALL (SUB65)
instruction in the same way as for ladder subprogram calling
from the second level ladder program.
Fig. 10.2.1(j) Calling block
(10) Block step (calling step sequence program)
To call a block from the step sequence program as a subprogram,
specify a block step in the step sequence program which calls the
block, as shown in Fig. 10.2.1 (k). This is called bloc nesting.
Fig. 10.2.1(k) Block nesting
The program shown in Fig. 10.2.1(k) is equivalent to in Fig.
10.2.1(l) which does not use a block step.
CALLU P2
CALLU P3
[ ]
[ ]
Ladder (Second level) Block2 (P2)
Block3 (P3)
Sn
( Pm )
(P2)
S231
S232
S233
Block 1 (P1) Block 2 (P2)
] S23
[ ]
S1
S21 S22
S3