1756-ENBT/A problems connecting

I've recently discovered a problem with a 1756-ENBT/A card, where i get the red X in linx and cannot browse to it, when sitting at my desk. The network wiring is basically this: IDF to a hub, hub to the ENBT card.

Also connected to the hub are two panelview plus 1000 HMI's. I can see those two HMI's through the hub, but cannot view my back plane and processor. When i go out to the machine, i can assign myself an IP, plug into the hub and see everything no problem.

I tried a different hub, same results. I checked the enbt firmware, its 6.006, processors is an L62 version 20.1. There didn't appear to be any errors in the enbt Ethernet stats tab when I was connected on the hub and poking around. Connections weren't outrageous, but i'd have to go back in and get specifics.

My question basically is, why can i see the HMI's, but not the ENBT on the given path across the plant network. I would assume something locked up on the IDF (Cisco 48 port managed hardware), bad cabling, things of that nature, but that i can see 2 out of 3 ip addresses on that path confuses me.

I plan to contact the admin dude guy person, but hes a mystical and awfully busy person, so i don't expect any immediate help in that regard since this isn't causing any downtime. All the interlocking is hardwired, this is just a minor/major inconvenience to me.

Do you really want a hub in there for some reason?
Can you ping it?
Can you see its web page?
Can you see it when connected directly, PC to ENBT?

I've inherited this, walked into many poorly installed system as part of taking this position, that said, the hub is utilized for port count the best I can figure. Adding places to plug in the 2 HMI's and the ENBT.

Perhaps i dont understand some of the questions. Ping what exactly? I can ping the two HMI's, but not the ENBT. There is nothing to ping on the hub. The HMI's dont support any web interface. When using the path described, i can only see the HMI's and not the ENBT. When i go to the machine and directly plug into the hub, i can then view all devices on the machine. I've changed out the hub and had the same symptoms. It is possible that there is a enterprise network issue, or bad cable from the managed IDF out to the machine, but i am confused on how to troubleshoot that since some but not all the devices are viewable on that suspect path.

Run tracert on your desktop to the ENBT. See where the packets stop.

And replace the hub with a switch

Thanks for the tip.

I ran the tracert for all 3 addresses. The HMI's had one hop, the PLC timed out on 30 tries, but all three addresses had the same first hit, which is a corporate IP address (which should be no surprise), but with a screen shot and a little ammo here, I've contacted the corporate IT admin and hopefully they will provide some insight.

Yep, they are blocking you. Good luck

So, the big lesson here is, being new to the organization: Trust but verify.

Missing gateway settings in the ENBT were the cause. I was tunnel visioned with other machine problems and probably the subconscious assumption that the card settings must have been correct when the line was installed. Thank you for the tips, I've now got a new tool so to speak, as there are plenty more networking issues between 4 buildings on the campus that have been left to linger. thanks again!

Thanks for the followup and feedback !

Yes, a missing or misconfigured Default Gateway will definitely make a PLC communicate on the local LAN, but not through a router/gateway/VPN.

Often the gateway is left null for that very reason...