AB 1769-L35 Network Dropouts

Hey Guys, thanks for taking the time to read this. I have an issue that we cant seem to put our finger on and solve. We have a host of plc's all SLC5/05 which are running great. We have had some expansion to the plant and our contractor has went down the road of installing the new Compact Logix L35 for the new plant. Going on 8 months in the drop outs have been progressivally getting worse every week. Drop outs would last less than 2 seconds and fault the entire plant with an error PLC Link Down.

I have recabled, changed switch and even changed Proccesor which leads me to think that there is a network issue but i cant put my finger on what is doing it. Network related the only change is that a new batch of ip cameras have been added to the network. Appreciate any thoughts.

Start by connecting to each switch via its webpage or terminal connection, and look at the traffic you have.
You might be having an RSTP (Rapid Spanning Tree) problem as well, disable that on every switch. Only enable RSTP if you need it, and know you need it in that location. By default, it seems most switches come with it enabled, which is just plain stupid.

+1.
The webpage of the 1769-L35 (I assume, -L35E) has a wealth of information...not easily decyphered, but very useful for this type of problem.
If it were all -L35's, I'd go on to say that the switch must be a managed switch, but, that's not the case.
I was at a highly networked site, and there were issues with AutoNeg of speed, between switch and processors...and that was easily detected by using the web page interface.
The only other alternative would be to install a small switch with port mirroring, and use WireShark to see the issue...not easy, and not for rookies.

Wireshark is sometimes a weapon of first resort !

IP cameras are about the most bandwidth-intensive application you can put on a network. If they are using multicast protocols and the network hasn't been equipped with switches that can manage multicast, they could easily overload the ability of other devices on the network to handle examining and discarding the multicast packets.

Wireshark will show multicast traffic "flooding" the network right away, without even needing to configure a mirror port or a network tap.

Hi and welcome to the Forum!

markquinn24 said:

...We have had some expansion to the plant and our contractor has went down the road of installing the new Compact Logix L35 for the new plant...Appreciate any thoughts.

Click to expand...

At a glance...

8 months ago, the CompactLogix 1769-L35E (if that's what you meant) was not a "new" controller option. To be honest, they probably should not have spec'd it for this job?

It only supports 32 CIP connections, which can be gobbled up quite quickly, depending on what it's communicating with. But we don't know what, so it's hard to say if that's all or part of the issue? It could be connections or multicast traffic issues?

What do the IP Cameras communicate with on the network?

They are undoubtedly resource hogs and most likely causing the issue, but if they are hammering the CompactLogix, then it "may" be the bottleneck, or it could be the lack of a suitable switch as Ken suggests.

Give as much detail on what talks to what on the network, what switches are there, if any, as well as starting to look deeper as the guys suggest.

The more you can divulge, the more we can assist you.

Regards
George

We have on 1769-l35e in our plant that we have issues all the time. I would recommend going with the 1769-l30er or 1769-l33er.