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.
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
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