Mitsubishi Electric MELSEC iQ-R Series User Manual page 262

■Multicast
This connection type allows multiple originators to receive data sent by one target.
When multiple originators establish a connection through multicast, the target sends send data for all the originators by using
one multicast packet. In addition, by using a switching hub with the IGMP snooping function, communication load on the
network can be reduced.
Multicast can be used only for Class1 communications. It cannot be used for UCMM communications or Class3
communications.
For the connection of the target communicating with an originator through multicast, when another originator opens a
connection through multicast, the same connection settings
If a request is made for communication based on connection settings different from those used for the active multicast
communication, an error occurs.
*1 A connection setting in which all of the following are matched: RPI, connection type, data size, transmission trigger, instance ID (or tag
name), and priority
(2)
Originator B
Receive data
(1) Originator A (scanner)
(2) Originator B (scanner)
(3) Target (adapter)
 Open a connection for which the connection type is set as multicast between originator A and the target.
 The target returns a response (normal) to originator A.
 The target sends data using a multicast packet.
 Originator A receives the multicast data sent in .
 Originator B opens a connection with the same connection settings for the target.
(Connection settings with all of RPI, connection type, instance ID (or tag name), data size, transmission trigger, and priority being the same)
 The target returns a response (normal) to originator B.
 Originator B receives the multicast data sent in .
12 FUNCTIONS
260
12.2 Cyclic Transmission Function
(3)
Target
Send data



*1
must be requested to the target.
(1)
Originator A

Receive data



EtherNet/IP communications