7. APPLICATION INSTRUCTIONS
7 − 70
MELSEC-A
Operation Errors In the following cases, operation error occurs and the error flag turns on.
• Access cannot be made to the special function module.
• The I/O number specified at "n1" is not a special function module.
• "n3" points, which begin with the device specified at (D), exceeds the specified
device range.
Program Examples TO
Program which sets three channels to the address 0 of buffer memory of A68AD,
loaded in I/O numbers 040 to 05F when X20 turns on.
DTO
The following program writes D1 value to A68AD (loaded in I/O numbers 040 to 05F)
buffer memory address 0 and D2 value to address 1 when X0 is switched on.
POINT
If a TO instruction is executed for a special function module frequently in a
short scan time, the objective special function module may fail to process
correctly.
To execute a TO instruction for a special function module, set the execution
intervals meeting the processing and conversion time of that module using the
timer and the constant scan function of it.
X000
0
P H K K K
TO 0004 0 3 1
• Coding
0 LD X000
1 TOP H0004 K0 K3 K1
10 END
X000
0
P H K K
DTO 0004 0 D1 1
• Coding
0 LD X000
1 DTOP H0004 K0 D1 K1
12 END
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