7. APPLICATION INSTRUCTIONS
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MELSEC-A
Operation Errors In the following cases, operation error occurs and the error flag turns on.
• Access to a special module/special block is not possible.
• n1 designation is other than 0 to 7
• When "n3" points which start with the device specified at (S) exceed the specified
device range.
REMARK
Set the order number of the special module/special block in question to "n1", counted from the
A1FXCPU.
Program Examples TO
The program to write 4603H to K0 of buffer memory in the second special
module/special block from the A1FXCPU when X20 is turned ON.
DTO
The program to write 2-point data beginning with D0 to K0 of buffer memory in the
second special module/special block from the A1FXCPU when X20 is turned ON.
REMARK
During the execution of the FROM/DFRO/TO/DTO instruction, M9119 can control the execution
of an interruption program.
• When M9119 is OFF (FROM/TO is given priority)
While the FROM/DFRO/TO/DTO instruction is executed, interrupt is disabled and interruption
program is not executed even at the occurrence of an interrupt.
For the interrupt occurred during the execution of the FROM/DFRO/TO/DTO instruction, the
interruption program that corresponds to the occurred interrupt is executed after the
completion of the FROM/DFRO/TO/DTO instruction.
While M9119 is OFF, the FROM/DFRO/TO/DTO instruction can be used in an interruption
program.
• When M9119 is ON (interrupt is given priority)
If an interrupt occurs during the execution of FROM/DFRO/TO/DTO instruction, execution of
the FROM/DFRO/TO/DTO instruction is suspended and the interruption program that
corresponds to the occurred interrupt is executed.
While M9119 is OFF, the FROM/DFRO/TO/DTO instruction cannot be used in an interruption
program.
• Objective interrupt is I0 to I5, I12, I13, and I29 to I31.
X020
0
HKHK
TO 0001 0 4603 1
X020
0
HK K
DTO 0001 0 D0 1
A1FXCPU
Expansion unit/
Expansion block
Special module/
Special block
Special module/
Special block
Set 0 at n1
Set 1 at n1
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