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12 Communications Performance and Communications Load
12-6
CJ-series EtherNet/IP Units Operation Manual for NJ-series CPU Unit (W495)
12-2 Adjusting the Communications Load
In an Ethernet network using an Ethernet switch, the network bandwidth is not shared by all of the
nodes; independent transmission paths are established between individual nodes through the Ethernet
switch.
A dedicated communications buffer is established in the Ethernet switch for communications between
the nodes and full-duplex communications (simultaneous transmission and reception) are performed
asynchronously with other transmission paths. The communications load in other transmission paths
does not affect communications, so packet collisions do not occur and stable, high-speed communica-
tions can be performed.
The Ethernet switch functions shown in the following table determine the performance of tag data links.
The following table shows the setting ranges of the tag data link settings that can be made for an Ether-
Net/IP Unit.
When the tag data link settings exceed the capabilities of the Ethernet switch being used, increase the
packet interval (RPI) value. Particularly when using an Ethernet switch that does not support multicast
filtering, the settings must be made considering that multicast packets will be sent even to nodes with-
out connection settings.
Additional Information
If the Network Configurator is used to set the connection type in the connection settings to a mul-
ticast connection, multicast packets will be used. If the connection type is set to a point-to-point
connection, multicast packets are not used.
In addition, if the required tag data link performance cannot be achieved with the Ethernet switch’s
capabilities, re-evaluate the overall network configuration and correct it by taking steps such as select-
ing a different Ethernet switch or splitting the network.
The following sections show how to check the device bandwidth being used by the tag data links in the
designed network, and how to set the appropriate values.
Item
Description
Buffer capacity
This is the amount of data that can be buffered when packets accumulate at
the Ethernet switch.
Multicast filtering
This function transfers multicast packets to specific nodes only.
QoS function
This function performs priority control on packet transfers.
Item
Description
Settings
Network bandwidth
Physical Ethernet baud rate
100 Mbps or 10 Mbps
Allowed tag data link communications
bandwidth
Maximum number of tag data link
packets that can be processed in 1
second (pps: packets per second)
6,000 pps max.
Connection resources
Number of connections that can be
established
256 max.
Packet interval (RPI: Requested
Packet Interval)
Refresh period for tag data
0.5 to 10,000 ms in 0.5-ms
increments
Содержание SYSMAC CJ1W-EIP21
Страница 8: ...Manual Structure 6 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 10: ...Sections in this Manual 8 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 20: ...Read and Understand this Manual 18 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 42: ...Revision History 40 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 68: ...1 Introduction 1 26 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 80: ...2 Installing Ethernet Networks 2 12 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 130: ...6 Testing Communications 6 4 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 206: ...7 Tag Data Link Functions 7 76 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 246: ...8 Message Communications 8 40 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 266: ...9 FTP Server 9 20 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 374: ...13 Troubleshooting 13 56 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495...
Страница 431: ...Index 1 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495 I Index...
Страница 436: ...Index 6 CJ series EtherNet IP Units Operation Manual for NJ series CPU Unit W495 Index...
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