Rockwell Automation Ethernet Design Considerations Reference Manual User Manual
Page 81
Rockwell Automation Publication ENET-RM002C-EN-P - May 2013
81
Predict System Performance
Chapter 5
Part One: Determine If System Has Sufficient Bandwidth to Meet
Application Requirements
To determine if your system has sufficient bandwidth to fulfill the requirements
of the application, complete the following steps.
1.
Draw an overall sketch of your system that includes all of the following:
•
Logix5000 controllers
•
EtherNet/IP communication modules
•
I/O modules
•
All connections to the network
Include a description of what the controllers are doing, such as messaging
with produced tags and any known RPI requirements.
2. Identify and count
each type of implicit connection for the system and
each EtherNet/IP communication module.
3.
Use the formulas provided later in this chapter to calculate the packet rate
capacity
loading on each EtherNet/IP communication module and the
available bandwidth for any unspecified RPIs.
4.
Based on the results of these calculations, decide if your system is
sufficient.
5.
If necessary, modify your system by doing one or more of the following:
•
For ControlLogix EtherNet/IP communication modules, upgrade to
newer series and/or firmware revision.
For example, the 1756-EN2T/A module, firmware revision 2.
x or
earlier module supports 10,000 pps. However, the 1756-EN2T/A
module, firmware revision 3.6 or later module supports 25,000 pps.
•
Increase some RPIs to let other RPIs in the system to decrease.
•
Change connection types, for example, direct to rack-optimized.
•
Change I/O module configurations, such as filter times, trigger types.
•
Add EtherNet/IP communication modules.
•
Add Logix controllers.
•
Verify that the network infrastructure can handle the system traffic.
•
Verify that the switches support full-duplex operation and IGMP
snooping. Port-mirroring is also important for switch and system
diagnostic functions.
6.
If you have to make modifications, verify that the modified system works
by recounting the connections and recalculating the packet rate capacity
loading.
TIP
We recommend your application’s EtherNet/IP links are no more than
60% utilized and QoS is implemented. Typically, these conditions
support most EtherNet/IP applications.
Step 3: Calculate
Step 4 or 6:
Does System
Work?
Yes
No
Step 5
Step 1: Draw Your
System
Step 7: Estimate Max
Times
Step 8: More
Throughput
Needed?
No
Yes
Done
Start
Step 2: Identify and
Count Connections
Part
One
Part Two
Go to Part Two
Steps described
on
.