Chapter 17 Label Communication Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

17
LABEL COMMUNICATION FUNCTION
This function reads/writes data from/to labels stored in a CPU module on another station.
Label communication flow
CPU module
(Label definition side)
Label assignment information
Label name
Label1
Label2
Label3
1.
Acquire label assignment information (device information) of the specified label with the mdGetLabelInfo function.
2.
Read/Write data from/to a device based on the acquired label assignment information (device information) with the
mdRandRLabelEx function or the mdRandWLabelEx function.
• In the label communication, a CPU module can be accessed without changing a user program by acquiring
label assignment information again even if the label assignment information of the CPU module is changed.
• The label assignment information (device information) acquired by using the mdGetLabelInfo function does
not need to be acquired for each execution of the mdRandRLabelEx function or the mdRandWLabelEx
function. However, if the label assignment information (device information) stored in a CPU module is
changed, acquire it again by using the mdGetLabelInfo function. (Otherwise, an error response is returned.)
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Obtain information of the corresponding devices
using specified labels (Label1, Label2).
Assignment target
(Device name)
D0
D1
X0
Execute Reading/Writing for the device
corresponding to the label.
MELSECWinCPU module
(Reference side)
User program
1.Execute the mdGetLabelInfo function.
2.Execute the mdRandRLabelEx/
mdRandWLabelEx functions.