Performing Message Communication; Example Of Message Communication Read - Mitsubishi QJ71DN91 User Manual

Devicenet master-slave module programmable logic controller
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7 PROGRAMMING WHEN EXECUTING THE MASTER FUNCTION

7.5 Performing Message Communication

7.5.1 Example of message communication read

Attribute read
command
Attribute read
command
7 - 8
This section explains an example of a sequence program that performs message
communication.
The following shows an example of a sequence program that reads attributes from
node number 3.
In sections enclosed with a dashed line, the area that is actually read and written as
well as the class ID, instance ID and attribute ID are different depending on the slave
node. Therefore, refer to the applicable manual of the slave node.
Error handling program
Attribute read
command
MELSEC-Q
Reads the master communication status.
Executes attribute read if the master
communication status is either C0
Sets the attribute read command.
Slave station of station No. 3,
class ID = 1
Instance ID = 1
Attribute ID = 7
Writes request data into the buffer memory.
Sets the message communication request.
Obtains the reception data read length.
Calculates the reception data read length.
Reads the reception data.
Resets the message communication request.
7 - 8
or 40
.
H
H

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