System Performance; Guidelines System Performance - Allen-Bradley SoftLogix 5800 User Manual

Appendix E System Performance Tuning Guidelines

System Performance

Table 12 - Parameters for Improved Performance
SoftLogix Parameter
Continuous task dwell time
Periodic save interval
CPU affinity
EtherNet/IP connections
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There are a number of configurable parameters in the SoftLogix 5800 controller
that affect the overall system performance of your personal computer. These are
the parameters.
Description
By default this value is 10 ms. Your application should be structured such that the continuous task contains programs
that are not time critical so that you can adjust the dwell time to a value as large as possible. For time critical tasks use
Periodic type tasks and be prudent in the number of periodic tasks and the configured period.
This parameter should also be set as large as possible to a value that is appropriate for your application. Every time the
periodic save runs, SoftLogix high priority tasks consume CPU time to save tag values and the user program to the
hard disk.
This setting does not affect the storing of online edits to the hard disk. Edits saved at:
• Next periodic save interval
• User-initiated save
• Controller shutdown
You can also observe the execution of the periodic save in the Windows Task Manager. It is possible that if you set the
time interval short and have a large number of tags that the periodic save runs continuously. This in itself is not an
anomaly, however as a goal, keep the overall CPU use below 80% on a continuous basis. This leaves headroom for other
Windows applications to run properly. If your system cannot be tuned to achieve this, then it is recommended you use
a dual Pentium personal computer or upgrading to a faster Pentium processor.
Use the CPU affinity setting on a dual Pentium processor personal computer to balance the overall system
performance. You can:
• Run control on one CPU and leave the second CPU for other Windows applications.
• Install two SoftLogix controllers in the virtual chassis and set the affinity of each to a different CPU.
For the best overall performance, especially when using integrated motion, use one SoftLogix controller in the virtual
chassis on a single CPU system.
The total number of connections from an EtherNet/IP port in a SoftLogix controller depends on the performance of the
computer running the controller. As you increase the number of connections, the performance of the computer
decreases.
Rockwell Automation Publication 1789-UM002K-EN-P - January 2015
The spikes show when the
periodic save is running.