Frontend Question from a Newbie

I’ve installed the complete trial package and am having problems with the frontend. In the OPC Server area, I have only ‘Remote Servers’ showing up. KEPServer is in fact running, I was able to configure a topic to view one of my Controllogix processors. I also have RSLinx running and it does not list it as well. I’ve done a refresh of the OPC servers and still nothing. Any help would be appreciated.


The OPC server list comes from a program called OPCEnum included with the OPC core components, which usually get installed by the OPC servers. In cases like this, there are basically 2 possible causes: 1) OPCEnum isn’t installed or 2) The DCOM security settings on the machine are prohibiting FactorySQL from accessing OPCEnum.

Go to the windows task manager and look at the “Processes” tab. Make sure “Show processes from all users” is selected at the bottom. Is OPCEnum.exe running? If not, it’s probably not installed correctly. I suggest shutting down all OPC related programs (your servers, the FactorySQL service), and then re-run the Inductive Automation installer. Select “custom install”. Under related software, select “OPC Core Components”. Restart the FactorySQL service and try to browse. Note: you could also try re-installing kepware, their installer usually does a good job of getting the OPC stuff in order as well.

If OPCEnum is running, DCOM security must be getting in the way. This is usually rare, since OPCEnum gets installed with program level settings that allow access to everyone. However, it’s not impossible that security could be getting in the way. If this seems to be the case, check the FactorySQL error log for any messages (Help->Log Viewer in the frontend), and we can go from there.


I checked the processes and opcenum is running. I did a complete uninstall and reinstalled and still have the same situation. The logviewer does indicate a problem with the OPCSystem. The message is ‘Error listing OPC servers: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))’
So it does appear to be a security problem of sorts. As a point of interest, I run 2 different hard drives in my notebook, I booted off the other, installed everything and it works fine. But for various reasons, I would like to get it running on the original drive.



There’s a CHM file on this thread that you can download that might help you get the dcom settings in order.

You said you booted off the other… that means you have 2 different versions of windows installed as well? What are the two versions?

One thing to note: all of the OPC calls come from the FactorySQL service (not the frontend or tray app), which by default runs under the SYSTEM account. As a quick fix/check you can try changing this to be the user that you log in as. To change it, go to Services under Control Panel->Administrative tool, right click FactorySQL and select Properties, and then change the user on the “log on” tab.

Let us know if that helps at all.


Still no luck. For some strange reason, I can’t view the help file (chm) either. Added the registry entries and restarted services. What I was saying before is I have 2 different harddrives, I swap them out depending on apps I am using. Both are using XP SP3, one is ‘cleaner’ than the other. I usually reserve it for strictly PLC and HMI programming as I’ve had problems in the past, especially with RSViewME crashing after I’ve installed other apps. Any more suggestions?


Well, those registry entries simply turn on DCOM logging, which can sometimes give you more info as to exactly why access is being denied. The messages appear in the windows event viewer, so check that out and see if there’s anything there.

Here’s a quick rundown of DCOM settings that you might check. First start by opening dcom config… Start->Run->dcomcnfg , expand Component Services, Computers, and then right-click “My Computer” and select properties.

  1. On “Default Properties” tab, make sure Default Authentication Level=None, Default Impersonation Level=Identify.
  2. On COM security, there are 4 buttons. Check that on all 4 “everyone” and “anonymous user” and “SYSTEM” have at least local rights. For troubleshooting you should add remote rights as well, because even on the local machine the communication can appear to be remote sometimes.
  3. Close that screen. Expand “My Computer” under dcom config. Select the “DCOM config” folder. Find OPCEnum, right click, select “Properties”. I should explain something quickly: most opc servers use the default settings you just set in 1 & 2, but OPCEnum usually sets its own, which is why I’m having you check this.
    General Tab: authentication level should be none.
    Location: Only “run app on this computer” checked.
    Security: usually all 3 will be custom. Click “edit” and make sure that the same accounts mentioned in #2 have access for everything.
    Endpoints tab: no change
    Identity: Set to “the system account”.

And that should be it. After doing all that, it’s probably best to restart windows. Also, make sure that the firewall is off, or at least TCP port 135 is open.