Network Comms Issue

[amil30]

I have an AB 1769 L18ER which is connected to our plant network via NAT device RAM 6021.

About a week ago, its connection to our Ignition SCADA system started acting funny. The device connection would alternate from connected to Idle and back regularly and the tags were unreadable.

I was also unable to connect to the PLC via it's NAT'd IP address even though I was still able to see it on RSLinx as well as attempt to go online with the controller. I was never able to connect to the controller and would always get a "failed to go online" error message.

We have multiple buildings with different VLANs so i brought the PLC and the NAT device to the building with our shop area. After changing the NAT address to match the VLAN of the building everything worked just fine, so the issue is with the network connection at the original location.

My question is, what is causing this and why did it all of the sudden start happening? How do i communicate this issue to be fixed with our IT team who has no knowledge of PLCs and automation in general?

Thanks,
Alex

 

[Cheeseface]

Disconnect the NAT from the public network and see if the IP is still active. Maybe someone connected another device with the same public IP.

 

[amil30]

Yes, i verified there were no connections at this address when I had my NAT disconnected.