Looking for some advice: We have some automation systems which have some Siemens devices communicating with Allen Bradley Compact Logix using Prosoft PLX32-EIP-PND communication gateways. From a hardware perspective, we have a single AB compact logix plc, connected to 4 separate and identical systems which each has a siemens CPU 1510SP F-1 PN connected to the AB via the PLX32-EIP-PND.
All 4 gateways and Siemens systems are exactly the same, aside from the IP address in the PLX32-EIP-PND that points to the AB plc. All systems were integrated at the same time. We have had issues with one of the systems losing communication between the Siemens and AB. My team has been fighting this issue now for months with neither our automation team nor the 3rd party equipment provider being able to figure out the cause. I just started a few weeks ago, so I was just recently brought up to speed on this. Previously, it sounds like nobody had ever connected to the systems when the fault was occurring (we didnt have the internal resources available to do so) . My first thought was the Prosoft, as I have seen a number of protocol converters fail over the years.
I helped my guys configure a new PLX32-EIP-PND and set the device name the other day, at which time we installed it. Fast forward to yesterday, and we see we are still intermittently losing communication between the AB and one of the Siemens systems (still the same one we replaced the PLX32-EIP-PND in). Yesterday, it had faulted and didn't come back online. I was able to finally get connected with the Siemens system while in this state. I could see active data on the ethernet port on the PLX32-EIP-PND that connects to the AB PLC, but there appeared to be no data between the PLX32-EIP-PND and the Siemens PLC. When I got online (in TIA Portal) I could see the PLX32-EIP-PND was showing as offline. I tried pinging it to no avail. All network connections looked good. All other network devices were still online. These connections do go through a small switch as well. Immediately after I unplugged network cable of the PLX32-EIP-PND and plugged it back in, the connection came back. For now, to rule out the network switch, I have swapped it between 2 of the Siemens systems (we will monitor to see if the fault follows the switch). In summary, we have replaced the PLX32-EIP-PND, and all thats between that and the Siemens plc is a small network switch. Looking back in history and it sounds like they have also tried a different ethernet cable as well, so I think that can be ruled out as the cause.
Any ideas from anyone what could cause a loss of communication to only 1 device?