User manual

Publication ENET-UM001I-EN-P - January 2010 151
Troubleshoot an EtherNet/IP Module Chapter 11
3. Review the System Resource Utilization table to evaluate your CPU
utilization.
4. Review the Missed field in the I/O Packet Counter Statistics table.
T
his field shows how many I/O packets have been missed. Your
EtherNet/IP comm
unication module may lose I/O packets due to:
• packets being produced faster than the connection’
s requested packet
interval (RPI). This happens for change-of-state connections or a new
consumer requesting a faster RPI than the first consumer.
• a packet having been received out of sequence.
a. If more than zero packets have been recorded
as lost, review the
Inhibited and Rejected fields in the I/O Packet Counter Statistics
table.
If the CPU utilization rate is Then
0...80% No action is required.
Important: This is the optimal rate.
Greater than 80% • Take steps to reduce your CPU utilization. See Internet Group Multicast Proto
col on
page 157 .
• Adjust your connection’s requested pac
ket interval (RPI).
• Reduce the number of devices connected to your module.
I
mportant: Your EtherNet/IP communication module can function at 10
0% CPU capacity,
but at or near this rate, you run the risk of CPU saturation and performance problems.