CHAPTER 4: MAINTENANCE AND TROUBLESHOOTING
SNAP PAC R-Series Controller User’s Guide
59
All three of these items should have a value of zero. If any of these items has a value other than zero, you may
have a network problem.
Analyze Communication Packets.
If it appears that you have network problems, you can use the
OptoEnetSniff
™
utility to log and analyze network communication packets. The utility is included with PAC
Project Basic and PAC Project Professional software suites, and is available on our website, www.opto22.com.
For help using the utility, see its online help file (choose Help
Contents).
Have Your Network Certified.
If you suspect network problems, you may need to have your network
professionally certified. Opto 22 does not offer network validation or certification services, but many network
hardware manufacturers do. Contact the manufacturer of your Ethernet network hardware to have them
diagnose, fix, and certify your network.
If you continue to have problems communicating with the SNAP PAC R-series controller after your network is
certified, contact Opto 22 Product Support. (See
Additional Troubleshooting Tools
Making Sure the Controller is in Normal Mode
If you are having trouble communicating with the controller, it might be in
fail-safe bootloader
mode
or
hardware test mode
. The controller restarts in one of these modes if you hold down the R
ESET
button longer
than the time needed to restore the default settings. For more information, see
.
TCP Settings
Retransmit timeout (RTO) refers to the length of time the controller waits while communicating before timing
out. The RTO is determined by the controller’s TCP/IP stack, and the stack continually recalculates the RTO
Ethernet Errors
