jkrom
Member
I've been dealing with a very frustrating problem that I hope the PLCS.net team can help with.
This machine is almost seven years old and we have two others that are virtually identical. It uses a PLC5/40 with Flex I/O and a TCP QuickPanel communicating via Remote I/O out of channel 1B @ 230.4k Baud.
About a month ago, seemingly out of nowhere, all of the remote racks started having intermittent faults. Looking at the Channel Status in Logix5, shows the fault status of every single rack going back and forth between faulted and clear ā but the number of retries is slightly different for each rack.
Initially, I replaced all of the blue hose and ran it outside of the cable tray that includes AC power, etc. to prevent noise interference. I also replaced the terminating resistors, checked the power at all of the remote racks and verified tight connections, etc. None of which made any difference to the symptoms.
During troubleshooting, I discovered that when the QuickPanel is disconnected from the RIO, all of the other devices work perfectly. I then tried swapping the QuickPanel with one of the other machines, but the problem did not follow the Quickpanel (i.e. the problem machine still had comm faults with the other HMI and the other machine worked fine with the suspect HMI).
The 5/40 was pretty close to being out of memory (only 75 words left) and I know that sometimes that can cause some strange problems, so I purchased a refurbed 5/60 and swapped it in with the exact same symptoms.
Anybody have thoughts on where to go next?
Thanks,
-Jim Krom
This machine is almost seven years old and we have two others that are virtually identical. It uses a PLC5/40 with Flex I/O and a TCP QuickPanel communicating via Remote I/O out of channel 1B @ 230.4k Baud.
About a month ago, seemingly out of nowhere, all of the remote racks started having intermittent faults. Looking at the Channel Status in Logix5, shows the fault status of every single rack going back and forth between faulted and clear ā but the number of retries is slightly different for each rack.
Initially, I replaced all of the blue hose and ran it outside of the cable tray that includes AC power, etc. to prevent noise interference. I also replaced the terminating resistors, checked the power at all of the remote racks and verified tight connections, etc. None of which made any difference to the symptoms.
During troubleshooting, I discovered that when the QuickPanel is disconnected from the RIO, all of the other devices work perfectly. I then tried swapping the QuickPanel with one of the other machines, but the problem did not follow the Quickpanel (i.e. the problem machine still had comm faults with the other HMI and the other machine worked fine with the suspect HMI).
The 5/40 was pretty close to being out of memory (only 75 words left) and I know that sometimes that can cause some strange problems, so I purchased a refurbed 5/60 and swapped it in with the exact same symptoms.
Anybody have thoughts on where to go next?
Thanks,
-Jim Krom
