1756-ENBT/A Connection issues

Darkzadow · Apr 12, 2012

Hi. I have 2 ENBT/A cards in my control logix rack. The first card which I think is starting to go bad as it goes from running to unconnected states without throwing errors. I am trying to put the communications onto the second not faulted (yet) card. When I directed the outside application to the 2nd cards IP i got a connection fault.

My questions are is the 'internal status' going from run mode to unconnected status a good indicator of a bad card? And If I set the Domain Name, Host Name, subnet, gateway, and dns Under Internet Protocol Tab. To identical as the first card(Physical Module IP is still unique) would that prevent an application from connecting to my control logix? Such as Host name conflicts or something?

Any clue as to being able to move connection would be amazing. Original card is failing more often.

The Plc Kid · Apr 12, 2012

Darkzadow said:
If I set the Domain Name, Host Name, subnet, gateway, and dns Under Internet Protocol Tab. To identical as the first card(Physical Module IP is still unique) would that prevent an application from connecting to my control logix? Such as Host name conflicts or something?

It depends. It could. We need to know more about the network topology and the devices connected to it to give a better answer. Just really not enough info here.

If the system is not part of a domain then you should not need to worry about domain name and host name and dns.

I would be checking cabling first if I were you. Are you devices connected to a switch? how does the connection to each device look? You may have a bad cable or connector from the switch to enbt. Check this first as it is cheap and easy to swap just replace the patch cable and monitor it.

Darkzadow · Apr 12, 2012

The system is part of a domain. I only have a basic knowledge of the network as I am just getting my feet wet with PLC programming. A pc on another part of the network sends PLC5 data to the Ethernet card. The configuration on that machine only points to an IP address and attempts to connect. So I thought that duplicating network settings in the second card and pointing the pc application to the new IP should in theory connect properly. The PC can ping both IP successfully. I will try switching network cables on the cards next time the card fails as any connection loss stops production.

Im sorry for little information as I don't know what information would be helpful. I tried to ignore the ethernet connections as the were working before I got hired and were something I wouldn't have to change for a while.

Darkzadow · Apr 12, 2012

I was able to get in contact with the PC admin and he told be that the PC uses IP address only. And that the host and domain are not updated to DNS unless requested. So as long as the card was under same subnet/ network area as the original card, pointing the PC at the other IP should establish communication with that card. PC application says connection refused when I try.

I am still waiting for opportunity to disconnect cables.

Would ethernet connection loss force the internal state from run mode to unconnected? I am trying to pinpoint if issue is internal to card or external such as wires and network.

The Plc Kid · Apr 12, 2012

It sounds like this system is connected to your corpoarte LAN? If so and you have a contrologix running firmware less than V18 you have multicast messaging being used and a lot of things could be causing this.

I take it that you dont have a spare ENBT to try? What is the ip address on both enbt unitss? It shouldbe scrolling across the ENBT display when it is running. Is it 192.168.1.xxx?

If this is the address range on both you can swap them and most likely change the last octet of the ip address with the rotary switch's on the card.

Mark Buskell · Apr 12, 2012

Have you used the Logix5000 Task monitor to check the network usage on the cards? We had one that was acting strange. After checking our usage, one ENBT card was running at 95 to 100 % and the other ENBT card was only as 10%. We moved some devices from one card to other card and the problem was solved.

Darkzadow · Apr 12, 2012

They are on the corporate LAN 10.123.219.21, and 10.123.219.100. They at at 30 and 15% utilization right now so I don't think the original was stressed. The control logix firmware is 18.

I was able to get it to reconnect by reseting the ENBT multiple times. I am holding off on re configuring the .100 card to .21 until it loses connection again or I get the line down. A couple of my co-workers suggested changing the ports the ethernet connects through. My new boss explicitness told me all major troubleshooting that brings the line down such as reconfiguring or unplugging connection was not going to happen unless it crashes again.

The Plc Kid · Apr 12, 2012

You mean your ENBT modules and their respective I/O are on the corporate network with other non automation devices?

Also if you are using multicast connections and you don't have managed switch's then you have a very unreliable and unpredictible system.

Is this a fairly new system or something that has been running for a long time. Automation equipment should never and I repeat neversit on the same subnet as other corporate network devices.

If you need a connection to the corporate lan then it should be from a seperate ENBT card.

The devices on each ENBT matter as each device uses so many logical connections not just 1 some devices use 1 and others 2,3 or 4 depending on many factors. ENBT is rated for 250 max but in most cases you will start having performance issues before that.

The Plc Kid · Apr 12, 2012

On most machines you want drives and I/O on one subnet and ENBT and HMI's PC's and other devices on another.

You may even want to split the drives and I/O on different subnets and ENBT modules dependign on how much you have and how it is setup.

In some cases your HMI's may be on the corporate lan but best practice is for IT to make a VLAN just for that and none of their other devices.

Kev77 · Apr 12, 2012

I have had issues in the past when someone changed the speed and duplex from auto to 100mb/full. The switch that they were plugged into was resetting to try and resolve the issue. If you go to the ENBT card web page, what errors do you see in the diagnostics? This can also help you track down the issue.

Darkzadow · Apr 13, 2012

The HMI are now on the separate card and drive IO is on a seperate card as well. The EBNT card is now only responsible for the PC application. It is a dedicated server that is sending automation order setting such as temp and hold times I am all on the production LAN. The corporate lan is on a different subnet that i dont have access to. Im sorry for the confusion. The application is a Rockwell Gateway Server. This refuses to talk to the working card. Giving a connection refused error. As of now the card is at 18% utilization and still has connection lost/ card failure.

The speed and duplex do not seem to have any effect as I have both cards at 100/full. The web page shows 10,000 IN errors under Interface counters that were not there yesterday. and half as many alignment errors and FCS errors.

So that would seem to indicate the card itself is bad.

Kev77 · Apr 13, 2012

CAn you try and unplug the card and hook up a laptop to the port and set the IP address on the laptop to the correct IP range and go to the device web page or connect to the processor using a good known cable and then watch the counters. This should narrow it down to the card if the counters still go up.

As far as the speed setting, is that a forced speed or set to Auto-negotiate? When you have a forced speed and Auto-negotiation you can see this problem.

Mark Buskell · Apr 13, 2012

You may also try switching the ENBT cards to see if the problem still occurs.

Darkzadow · Apr 13, 2012

I will have the line completely to myself to disconnect and check individual settings on sunday so I was going to try to force the Gateway server application onto the working card. There is no spare ethernet card.

I have the speeds forced in both cards as that was how the failing card was setup before I was hired. I think it was forced as there would be times where 100 mbs was needed even though auto would default to 10

Darkzadow · Apr 13, 2012

I will try removing the 'bad' card then and configuring the working card with the IP address of the other. Sunday I basically will be trying every hardware ethernet and IP configurations I can to either get the old card working properly or temporarily get the server connection and HMI on the working card (using either IP address).

1756-ENBT/A Connection issues

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