Chapter 5 Instruction Specifications
5-108
Syntax of FOR to NEXT
FOR 1 (WR0010)
NEXT 2
NEXT 5
FOR 5 (WM04F)
Program
Program
Program
Program
Program
NEXT 3
FOR 3
Program
Program
Program
FOR 3 (WR10)
NEXT 3
SB1
NEXT 2
FOR 3(WR0003)
RTS
SB2
NEXT 3
FOR 4(WR0004)
RTS
INT0
NEXT 4
NEXT 1
RT1
FOR 1(WR0001)
FOR 2(WR0002)
END
FOR3
Program
FOR 1 (WM001)
NEXT 1
Program
Program
FOR 2 (WM002)
NEXT 2
FOR 1 (WM001)
CJMP 10 (X00000)
NEXT 1
LBL10
FOR 1(WR0001)
FOR 2(WR0002)
FOR 3(WR0003)
FOR 4(WR0004)
FOR 5(WR0005)
FOR 6(WR0006)
NEXT 6
NEXT 5
NEXT 4
NEXT 3
NEXT 2
NEXT 1
X00000 JMP 1
FOR 1(WM001)
NEXT 1
LBL 1
Program C
WR0010=1
WR0010=20
FOR 1(WR0010)
Program A
NEXT1
R005
Program B
FOR 1(WM001) to NEXT 1 will execute
normally.
•Nesting error
When WM002=0
Since FOR 1(WM001) to NEXT 1 is
prioritized, jump will not be performed
over NEXT 1 from FOR 2 to NEXT 2.
At this time, NEXT 2 generates a FOR
2 undefined error.
When WM002 ≠ 0
FOR 2 will not do anything. Therefore,
NEXT 2 will generate a FOR 2
undefined error.
•When R005 is off
Program B is executed after program A is repeated 20
times.
•When R005 is on
The repeat counter WR0010 changes to 1, and since the
NEXT 1 processing subtracts 1 from it, the content of
WR0010 becomes 0. Therefore, the repeating of
program A is terminated and program B is execute
4] Use FOR to NEXT as a nest.
8] The number of repeats may be modified within the
program.
The content of WR0010
decrements by 1 and a jump is
performed to FOR 1 (WR0010).
1] A NEXT instruction with the same code number as the
code number n of the FOR instruction is required after
the FOR instruction.
5] It is possible to escape from a FOR to NEXT loop
using a jump instruction.
•NEXT undefined error
The NEXT instruction with
respect to the FOR instruction
does not exist within the user
program.
•FOR undefined error
The FOR instruction does not exist
before the NEXT instruction.
•NEXT to FOR error
The NEXT instruction exists
before the FOR instruction.
The FOR 1 to NEXT 1 loop is
escaped when X00000 turns on
before the loop has been repeated
for the set number of repeats
(content of WM001).
2] An overlap of FOR and NEXT instructions with the
same code number n is not allowed.
6] FOR to NEXT may be nested up to 5 levels. When a
subroutine is included, the FOR to NEXT within the
subroutine is counted.
•Nesting overflow error
•FOR duplicate-definition error
A FOR instruction with the same
code number n is programmed.
•NEXT duplicate-definition error
A NEXT instruction with the same
code number n is programmed.
Note: FOR and NEXT duplicate-
definition errors will occur
during operation pre-processing.
3] FOR and NEXT must be within the same area.
7] Do not include a startup condition between FOR and
NEXT. If a startup condition is required, create a
circuit as shown below:
Program head
Normal scan
Subroutine
SB1
Subroutine
SB2
Interrupt scan
[Operation description]
When X00000 is off, program C is
repeatedly executed for the
number of WM 1 times.
When X00000 is on, program C is
not executed since a jump is
performed from JMP 1 to LBL 1.
NEXT n