Overview; Summary; Cpu Time; Network - Omron CX-Supervisor User Manual

CX-Supervisor Performance monitor

C.4.1 Overview

C.4.2 Summary

C.4.3 CPU Time

C.4.4 Network

C.4.5 PLC

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Shows an overview of the headline performance of all other components.
Provides a Summary view, totalising and averaging property values from all
PLCs on all networks.
Lists specific CPU and process information including processing times for all
scripts and all callbacks.
Totalises properties for all PLCs on each network.
The 'PLC Average Latency (ms)' field shows the physical delay of the network
and PLC response time. Depending on the PLC, setup and network this
should be 9-30ms. If this is drastically higher it could be the cause of
performance problems. Try some of the following steps to reduce it:
The 'PLC Average Latency (ms)' field shows the physical delay of the network
and PLC response time. Depending on the PLC, setup and network this
should be 9-30ms. If this is drastically higher it could be the cause of
performance problems. Try some of the following steps to reduce it:
• Test on a dedicated network, or if not possible with other nodes disabled.
This is to ensure it is not due to network loading or other external factors.
• Try with the PLC in 'STOP' mode. If this has an impact double-check the
PLC settings. This can vary depending on PLC type, but some require a
longer scan rate, so more free CPU time is available to service the
communications, whereas some require a shorter scan rate so the
communications are service more frequently at the end of each scan.
Some other settings may also impact the CPUs ability to service
communications.
• Try to reduce the number of active messages (see below)
• Try to reduce to % usage (see below)
On the Performance tab, the quantity of 'Active Messages' is shown. Each
Active Message is a single communication request although the internal
optimisations mean that many continuously addressed points can be read in
one message. This depends on the frame size, which in turn depends on the
network type. This is why use of arrays and good memory layout are essential
to performance. To reduce the Active Messages see Chapter 16 Best
Practices, Performance and Chapter 16 Best Practices, Points.
On the Performance tab, the current and historic usage is shown. 100% usage
is rarely seen and the system may be running at capacity well before this. This
is analogous to a motorway where cars slow down long before they are
touching bumpers, and might only achieve 50% of capacity (each car has a
car length space behind it). In practical terms, for serial connections consider
70-80% the limit. For Ethernet packet collisions start occurring above 30% and
are automatically corrected, but 40-50% is the practical limit. For Controller
Link, which has a vast bandwidth, any value above 10% signals a
performance issue. To reduce the % usage see Chapter 16 Best Practices,
Performance and Chapter 16 Best Practices, Points.
Appendix C Troubleshooting