Intermittent comm loss to 5/05 and Rslinx

Hello
I ran into a problem today that i'm hoping to get some ideas on what could be the cause. I have a 5/05 connected to a enthernet switch which communicates with a HMI and the plant scada system. The system has been running for 3 years with no problems until lately.Several times a day the HMI will display icons showing that it has lost communication with the plc, the HMI is also connected to the ethernet switch. When i monitor Rslinx from our terminal in operations the icon for the 5/05 processor will display a red X for a couple seconds then go away for a few minutes then i see the red X again. The connection from building to building is fibre optic, but i'm thinking the problem isn't in the f/o because of the loss of communication with the HMI which is located in the same enclosure as the 5/05 and the f/o switch which i should mention i replaced with a new spare to see if it would fix the problem. Anyone have an idea what else to check.

The general-purpose troubleshooting question is: 'what changed' ?

Your description points to a media problem between the SLC-5/05 and the Ethernet switch, or a capacity problem in the SLC-5/05 controller.

Start by viewing the diagnostic webpage of the SLC-5/05 to see if it indicates any media or signal errors.

Is the switch a managed unit that can show you any diagnostics on the link or per-port ?

No changes have been made to the hardware or the program. I'm not sure that i know how to find the webpage you mentioned. The switch does not have that type of features.Is it correct to assume that it is not a fibre optic problem?

I haven't troubleshot an SLC-5/05 web page lately, but for all A-B Ethernet devices there is an embedded web page that gives at least basic diagnostics or information about the device. The one in the 1756-ENBT and -EN2T is quite extensive.

Just type the IP address of your controller, like "192.168.1.10" into the address bar of any Web browser.

For downloading diagnostic web pages for future examination, I very much like the ease of use of the utility HTTRACK. WGET is smaller and lighter but a lot of work to use right. In a pinch, screenshots work too. That will get me started on how much I enjoy FastStone Capture....

In RSLogix 500, you can also create a Data File that will be the Diagnostic File for the Ethernet channel, to show you the number of frames going in and out of the port, as well as showing you any physical errors detected by the port. Go into RSLogix 500 and select Channel Configuration, then enter an unused Data File number for the Diagnostic File field. Creation of new data files must be done offline for SLC controllers.

cirtcele said:

I'm not sure that i know how to find the webpage you mentioned. ?

Click to expand...

I think the way to get to the web page is, open a web browser IE firefox ,
then type in the address of the PLC into the address bar.
Again I say I think

edit
OH well fast finger Ken was there

Thanks Ken and Gil. I'll give it a try tomorrow morning.

I agree that if a local HMI and a remote (over F/O link) HMI both get communication errors then the problem is likely local to the SLC-5/05.

This doesn't mean the problem does not originate elsewhere; maybe there is traffic flooding the network that is "blinding" the HMIs or the SLC. That's why we troubleshoot, eh ?

The usual arsenal of tools will come out: open a command prompt and PING the controller's IP address. Set PING for a hundred repeats and see how many get through.

There are a lot of other Ethernet tools to be used. I like to at least verify the physical connection by checking the controller's statistics and anything I can learn about the switch and the cable system before looking into controller capacity or throughput or programming.

I have had a simular problem befor, Our SCADA system runs 24 hours a day all year round and has been for years. We had a problem with the SLC5/05 side of PLCs where our HMI Factory talk would view the tags assosiated with some of the SLC's as bad tags and thus you would lose the graphics and values associated with the tags.This is all ethernet. Quite simply i tried a few different tools and tests to remedy this and in the end i did the good old rockwell reboot (power off then back on) and the problem has not returned. Quite frankley i think the SLC 5/05's have a few bugs even with the latest firm ware.
Hope this helps

Thanks to all and special thanks to Mr.Ken Roach,
Sir,
You please try by replacing the RJ45 (stright cable)cable between the HMI and switch and befor plugging at hmi side please try to ping(by your laptop) the SLC ip adress in the run command as ping xxx.xxx.xxx.xxx -t(here -t is for continues pinging) and let me know the screen shot of the cmd outcome....so than we can fix the problem finally...

I hope its a quite simple problem to fix.

Thanks in advance for your better understandings.

Nagaraj.
09902003484.

Hi Guys
I tried pinging the 5/05 100 times as Ken suggested the first place i tried was from the switch in the operations building it lost 23 out of 100. The second time i tried was at the switch in the same enclosure as the 5/05 lost 29 out of 100. The third time i plugged my laptop directly into the ethernet port on the 5/05 lost 22 out of 100. So it looks to me like the problem is with the 5/05 processor, as i stated in a earlier post no changes have been made to the program or port settings. Processor comm board going bad?

cirtcele said:

Hi Guys
I tried pinging the 5/05 100 times as Ken suggested the first place i tried was from the switch in the operations building it lost 23 out of 100. The second time i tried was at the switch in the same enclosure as the 5/05 lost 29 out of 100. The third time i plugged my laptop directly into the ethernet port on the 5/05 lost 22 out of 100. So it looks to me like the problem is with the 5/05 processor, as i stated in a earlier post no changes have been made to the program or port settings. Processor comm board going bad?

Click to expand...

I wouldn't be so sure it's the processor. A bad power supply can cause similar problems. Try swapping power suppliers with another controller.

please send me the screen shot of channel-1 configuration of slc5/05...so that i will try to fix the problem...
Rockwell will recomend to select Auto Negotiate.

Not sure how to post the screen shot i'll just type it.
channel 1 -driver: ethernet
broadcast address: 0.0.0.0
ip address: 192.168.101.8
subnet mask:255.255.255.0
gateway address:0.0.0.0
msg connection timeout (x 1ms): 15000
msg reply timeout (x ms): 3000
inactivity timeout (x ms): 30
bootp enable: no
bootp valid: no
snmp enable: yes
http enable: yes
auto negotiate enable: no
port speed enable: 100mbps full duplex forced
contact:
location:
hardware address: 00:00:bc:30:39:11

I have had A/B recommend not using Autonegotiate, but I think you are past that possibility when you are connected directly to the SLC and have a 75% success rate with a ping command, that points to a bad port on the CPU. This is ASSuming that you have verified that your laptop and cable are not the problem...you earlier evidence suggests that it's not but it would be a good idea to use the same PC and cable and ping test another device just for confirmation.

We have had one 5/05 do silly things like that, and the replacement took care of the problem.

Also, you might look at the number of connections that the 5/05 is using. I had a problem with some messaging edits once, and found out that my edits caused some new connections to be created, putting me over the limit, and it took 30 minutes for the old ones to be released.

You need to have a channel diagnostic file assigned in order to view those stats with RSLogix500 (Look under Channel Configuration, Channel Status, Channel 1).

Paul

I tried a different cable today with the same results. There is another plc in the same building that is sharing the same switch, i can plug my laptop into the switch ping the other 5/05 and get no errors. Then ping the problem plc and get 20 some errors.