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10.2
Precautions for Dedicated Instructions
10.2.1
Precautions for dedicated instructions (common)
The following describes precautions when using dedicated instructions.
(1) When changing data specified by dedicated instructions
Do not change any data (e.g. control data) until execution of the dedicated instruction is completed.
(2) When the dedicated instruction is not completed
Check whether the mode of the master/local module is online.
A dedicated instruction cannot be executed when the mode is offline.
(3) When accessing another station by a dedicated instruction during CC-Link IE
Field Network diagnostics
Execution of a dedicated instruction may take some time. To reduce the waiting time, perform the CC-Link IE
Field Network diagnostics using the following methods and then execute the dedicated instruction.
(a) Using the COM instruction
After communication with GX Works2 using the COM instruction, execute the dedicated instruction.
1.
Store 0 in the Selection of refresh processing during COM instruction execution (SD778).
2.
Turn on the Selection of link refresh processing during COM instruction execution (SM775).
3.
When the COM instruction is executed, communication with GX Works2 is executed.
4.
Use a dedicated instruction to access another station.
(b) Using the service processing setting
In the service processing setting of PLC Parameter (PLC System) of GX Works2, secure 2 or 3 ms for the
service processing time.
Remark
For details on the COM instruction, refer to the following.
MELSEC-Q/L Programming Manual (Common Instruction)
(4) When using the submaster function
Refer to Page 198, Section 8.8.4 (2) and Page 204, Section 8.8.7 (9).
MOV
H0
SD778
SM402
COM
SET SM775
Start contact
Dedicated Instruction