Micrologix 1200 networking

Good morning all,

We have a micrologix 1200 that we are using to control our plant water operation. We are having an issue with being able to communicate to it remotely. The PLC is currently connected to a AB 1747-DPS2 DFI port splitter and from the port splitter to an AB 1761-NET ENI, then out of the ENI to a NetGear ProSafe 5 port gigabit switch. The PLC is connected to a panel view through the router as well. The issue we are having is that we cannot seem to connect to the processor if another PC is connected to it. When we disconnect from it we have a hard time getting it to connect with a different PC. We are able to ping the processor successfully but RSLinx does not see it. Not sure if it can handle multiple connections or not so I just wanted to see what you think and if there might be other options for networking this system. Hopefully this makes sense but if not please ask any questions you have and I will do my best to answer them.

If possible, i would suggest replacing the Micrologix1200 with a Micrologix1100 or 1400, depending on the IO count. Both models have built in ethernet. IMO, the increase in both network performance and the ability to perform online edits is well worth the price.

It doesn't take much to overload a net-ENI and the serial connection they use. If you have a panelview pulling a fair amount of data, its very possible it is overloaded when you also connect a programming PC to it.

It sounds like this little controller and its network interface are being asked to do too much, and I agree that a more-powerful controller like the MicroLogix 1400 would be a welcome upgrade.

We are able to ping the processor successfully but RSLinx does not see it.

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This is a classic symptom of the 1761-NET-ENI being out of TCP/IP connections.

It supports up to six; two inbound, two outbound, and two in either direction.

But it's easy to take up a TCP/IP connection inadvertently if the Net-ENI is connected to a factory network. For example, an unrelated RSLinx Classic instance browsing the network with RSWho can detect the Net-ENI, then open a TCP connection to it so that it can query its identity. Poof, there goes one of your four precious connections. And they don't time out from inactivity for quite a while.

You can connect to the Net-ENI with Telnet to inquire about its TCP connection usage; the instructions are in RA Knowledgebase Article ID # 27418 (TechConnect Required)

If upgrading to a MicroLogix 1400 isn't in the budget, consider replacing the 1761-NET-ENI with a Digi One IAP. The Digi (designed by the same guy, actually) has a reputation for better stability and more connection capacity.

i can get on the web interface with the net eni and it shows only 3 connections. When you say that rswho might take up a connection would that show up. See attached picture showing connection. 1 is a laptop 2 is a panel veiw 3 is a modbus over ip.

Data-Linc Group also has a device similar to the NET-ENI. The NET620 (the DLG unit) will support up to 10 connections and is very simple to setup.

could i eliminate the AB 1747-DPS2 DFI port splitter and just plug the PLC directly into the Net ENI? would this help at all?