Adjusting The Communications Load - Omron NX-SL3300 User Manual

9 Communications Load
9-1

Adjusting the Communications Load

In an Ethernet network using an Ethernet switch, the network bandwidth is not shared by all of the no-
des, and independent transmission paths are established between individual nodes through the Ether-
net 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, therefore packet collisions do not occur, and stable high-speed com-
munications can be performed.
The Ethernet switch functions shown in the following table determine the performance of the CIP Safe-
ty connections and tag data links.
Buffer capacity
Multi-cast filtering
QoS function
The following table shows the specifications within which the CIP Safety Connection settings and the
tag data link settings can be made for a built-in EtherNet/IP port.
Item
Network bandwidth
Maximum number of
packets per second
Number of CIP Safe-
ty routing connec-
tions
Packet interval of
CIP Safety connec-
tions
(EPI: Expected
Packet Interval)
Tag data link con-
nection resources
Packet interval of tag
data links
(RPI: Requested
Packet Interval)
When the CIP Safety connection settings or the tag data link settings exceed the capabilities of the
Ethernet switch, adjust (increase) the packet interval value (RPI/EPI).
9 - 2
Item
This is the amount of data that can be buffered when the data
packets accumulate at the Ethernet switch.
The function transfers multi-cast packets to specific nodes only.
The function performs priority control of packet transfers.
Meaning
Physical Ethernet 100 Mbps or 10 Mbps
baud rate
The maximum num- 12,000 pps max (total of 12,000 pps with two ports)
ber of packets that
can be processed in
one second (pps:
packet per second)
Maximum safety I/O 16 max (total of 16 with two ports)
connections support-
ed for routing
Data refresh period 1 to 500 ms in 1-ms increments. The allowable range depends
of CIP Safety con- on the target device.
nections
The number of tag 32 max (total of 64 with two ports)
data link connec-
tions that can be
opened
Refresh period for 1 to 10,000 ms in 1-ms increments
tag data
Description
NX-series CPU Unit
NX102
NX-series Safety Control Unit User's Manual (Z930)