Help! SLC505-rslinx-ethernet problem

hatchor

Member
Join Date
Feb 2008
Location
Melbourne
Posts
13
Hi all,

I am having a problem that I would really like some guidance with. I will give as much information as I can……I am not a PLC programmer, just local IT support.



  • I have an automotive manufacturing environment running an ERP system that connects to RSLinx 2.51 Gateway through a third party VB application over OPC. RSLinx connects to three SLC505’s and the entire network is over Ethernet using VLans. The SLC’s and RSLinx are on the same VLAN. There are about 22 production computers that use this third party VB app to communicate to RSLinx to update registers on the SLC’s (Eg. Change N212:1/0 to N212:1/1).
  • RSLinx and the production computers are running XP pro SP2. They all use the same login which is also set to be a local administrator. I have configured the DCOM and port settings according to Rockwell recommendations and downloaded and run the XPSP2 configuration utility from Rockwell. The windows firewall on all the computers is disabled.
  • The three topics for the SLC’s are setup and defined in RSLinx using the AB_ETH driver, and are shown in RSwho with no problems. All good.
  • After about 1 day of running and processing requests, the connection between RSLinx and the SLC’s seems to drop. The topics are still active and look normal in RSWho. I can open the OPC group diagnostics window and see the open connections from the production computers to RSLinx. I can ping the RSLinx machine. I get no response from my third party VB application which waits for an acknowledgement that the transaction to the SLC has been successful. The fix for this is to restart the RSLinx machine and this restores the connection (or unfreezes RSLinx…?) to the SLC’s.
  • So, to keep production happy we have been restarting the RSLinx server every morning just to obtain a full day of production without having a failure. If we don’t restart, or restart the night before, then we get a failure during the day. There is no event recorded in the windows event log, or in the communications event log of RSlinx. It is like there is some sort of overflow when there has been too many transactions in RSlinx?
  • The only thing I have left to try (that I can think of…) is to properly protect the SLC’s network ports using the managed switch and only allowing access from the RSLinx machine and the 2 machines that have RSLogix installed. I have heard that unsolicited messages or crappy network traffic can ‘take’ communication channels on the SLC, forcing it to disconnect the RSLinx connection. I don’t know if this makes sense? The maintenance personnel here are either electricians or boilermakers with little in-depth PLC knowledge, just some ladder programming knowledge, and don’t have great communications knowledge with the SLC’s.
  • It is worthwhile to note that we were stable with the system on an older version of RSLinx and running Win2k throughout. Only after some of the windows updates for security etc (around 2k SP2) came out did we start having issues. Being a global company with specific IT requirements, we need to run on XPSP2 and also have all windows updates installed regularly, so the possibility of using older more stable systems is not there.


In essence I don’t know if it is an RSLinx problem, RSLinx configuration problem, a windows problem, a networking problem, or all of the above combined? I have had a Rockwell support engineer on-site to try and diagnose what the problem could be. This was at another site with the same company, same environment. I didn’t really get the results I was looking for from the technicians few visits. In the USA we have the same scenario but RSLinx is running on Windows Server 2003 and the PLC’s are protected by a managed switch in the fashion I have stated above. The difference there is that they use controlLogix tags, and not registers.



If anyone could provide guidance or assistance it would be greatly appreciated. I am out of ideas as to what could be causing this and I really hope that someone out there has come across this problem or might know what could be causing it.



Thanks in advance
 
First I am not AB expert,But from above you say,I think if you want use
OPC Connect the third part,you should check something follow:
first :check when you ping the third PC is connected
second:you should config the third part PC's Dcomcnfg and youself's PC
Above all is my personal suggestion,you should care
good luck!
 
Thanks for the suggestion John, but just to clarify,

1. The third party software is an OPC client (that connects to RSLinx) and is located on the production line computers. My ERP system calls the third party software with parameters (eg. Topic, register(s) to update, wait or execute).I can ping these computers when the fault happens and have no reason to think that it is a failure on the part of the OPC client software because when the fault occurs, the software still connects to RSLinx and can be shown in the OPC group diagnostics.

2. The DCOMCNFG is configured on these computers according to Rockwell specs, and also on the machine running RSlinx.
 
Last edited:
The third party software is an OPC client .....
My ERP system calls the third party software with parameters (eg. Topic, register(s) to update, wait or execute).....

Hi hatchor, from above words i wonder what protocol you use to connect the third part direct,and you say the third part is act as OPC Client,what protocol or method you use to connect the third part with you ERP system?
 
Hi John, The OPC Client executable is called by the ERP program on each individual computer with parameters, eg, the ERP system would call the following command to activate the N212:2/1 register on the RSLinx topic called REARSLC505 c:\thirdpartyOPCclient.exe REARSLC505,212:2/1,EXECUTE
So the third party software is called from our ERP with a direct command.
I don't know a great deal about the third party software that interfaces the ERP with RSLinx, but it is a local installation on every computer that needs this interfacing capability.

Thanks for the questions John, I wish I could provide even more information, but this third party software was written in Brazil and I am not the system owner, just the poor local support guy trying to get it working! haha, cheers
 
Hi hatchor,first I think you should check the formats of the command is right,and then you should ask the third part's soft programer,and you will get more valuable message,may be the error because of the third part soft,good luck
 
hatchor,

Devices used on AB networks (i.e. Ethernet, ControlNet, DeviceNet, etc.) needs to be recongnized by the Rockwell's software. Rockwell uses EDS files to provide the necessary information about their software. In the case of third party devices the EDS files and other necessary configuration files are generally provided by the third party vendor. It may be possible that the third party EDS and/or configuration files may be corrupt, out of date, etc. and Rockwell does not support these files. You may want to try to contact your third party vendor if possible.

Good luck,
 
I have never used RSLinx as a general OPC server. But one thhing I would try is to issue an OPC client request from the machine running RSLinx using something like Excel or a general purpose OPC test client. That may help limit the scope of your issue.

If RSLinx sees a happy connection to the SLCs I would have to suspect that the RSLinx to SLC comm link is valid. Do you have RSLogix500 loaded on the OPC server machine? You could try connecting the SLC's using that. However, I think RSLogix connections are DDE client connections. But as far as the plcs are concerned it doesn't make a difference.

Keith
 
Thanks BDC man, I don't know much about OPC, but if the third party software is just configured to communicate to RSlinx using OPC, would it need EDS files etc? I will attempt to investigate how the third party software communicates with RSlinx.
 
hatchor,

Also, Rockwell Automation processors are only designed to operate on 802.3 10Base Ethernet networks. If the computers are on a network other than 10Base, a bridge or a router device will be required to connect the computers on one type of network to the processors on the 10Base Ethernet network.

Hope this helps,

Good luck,
 
Kamenges, thanks for the suggestion. When the failure occurs I can open and configure a new OPC test using the inbuilt Rockwell OPC test client. I can browse all the registers etc on the three SLC505's, so I guess that means that the comm link between RSLinx and the SLC's is OK...
 
The network is a mixture, but the managed switches are autosensing for speed and all the network is connected to a Cisco router. Thanks,
 
hatcher
Because between you ERP system and the third part,the net for you is all,and i think you could not think the SLC system,when the third part choice OPC protocol communication with SLC and the communication is ok,so you task just to send command activate the third part Soft send command by opc protocol to SLC,if you sure you send the command is ok,
just check the third soft only!
goog luck!
 

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