Melsec Data Link Functions; Program Processing - Mitsubishi Electric MELSEC iQ-R C Series Programming Manual

1.3

MELSEC Data Link Functions

MELSEC data link functions are the integrated communication function libraries which are independent of the communication
protocols.
A program to communicate with a CPU module can be created regardless of a target hardware or communication protocols
by using the MELSEC data link functions.
The communication functions supported by the MELSEC data link functions are as follows:
Communication function
Bus interface communication
CC-Link IE Controller Network communication
CC-Link IE Field Network communication
CC-Link IE TSN communication
MELSECNET/H network communication
CC-Link communication

Program processing

The following shows the user program processing using the MELSEC data link function.
When accessing with a device name
1.
Start a task.
2.
Open a communication line. (mdOpen function)
3.
Perform dummy access (such as device/model name reading) to an access target.
4.
Access the target by using the MELSEC data link function.
5.
To stop accessing the target, go to the procedure 6.
To access the target again, go back to the procedure 4.
6.
Close the communication line. (mdClose function)
7.
Complete the task.
When accessing with a label name
1.
Start a task.
2.
Open a communication line. (mdOpen function)
3.
Acquire device information (label assignment information) from a target CPU module. (mdGetLabelInfo function)
4.
Access the target CPU module by using the acquired device information (label assignment information).
(mdRandRLabelEx/mdRandWLabelEx function)
5.
Check if there is no change in the device information (label assignment information) of the target CPU module.
If it is changed, go back to the procedure 3.
6.
To stop accessing the target, go to the procedure 7.
To access the target again, go back to the procedure 4.
7.
Close the communication line. (mdClose function)
8.
Complete the task.
1 COMMON ITEMS
14
1.3 MELSEC Data Link Functions
Description
Accesses a CPU module mounted on the same base unit.
Accesses a CPU module on the CC-Link IE Controller Network via a CC-Link IE Controller Network
module.
Accesses a CPU module on the CC-Link IE Field Network via a CC-Link IE Field Network module.
Accesses a CPU module on the CC-Link IE TSN via a CC-Link IE TSN module.
Accesses a CPU module on the MELSECNET/H network via a MELSECNET/H network module.
Accesses a CPU module on the CC-Link via a CC-Link module.