Professional OPC
Development Tools

logos

Online Forums

Technical support is provided through Support Forums below. Anybody can view them; you need to Register/Login to our site (see links in upper right corner) in order to Post questions. You do not have to be a licensed user of our product.

Please read Rules for forum posts before reporting your issue or asking a question. OPC Labs team is actively monitoring the forums, and replies as soon as possible. Various technical information can also be found in our Knowledge Base. For your convenience, we have also assembled a Frequently Asked Questions page.

Do not use the Contact page for technical issues.

Access is denied error

More
14 Jan 2013 20:38 #1175 by gmessoroch
Correct.

Please Log in or Create an account to join the conversation.

More
14 Jan 2013 19:53 #1174 by support
Replied by support on topic Re: Access is denied error
Thank you. Let me just verify it: With set up described in #2, even the application built with QuickOPC can start the AXS4ICCP service - but cannot truly access it (make operations on it). Is that correct?

Please Log in or Create an account to join the conversation.

More
14 Jan 2013 19:49 #1173 by gmessoroch
1. Yes the service is already running when trying to connect to. Both OPC server were configured with Local System Account as the log on user. With the Local System Account no server startup after a connection attempt.
2. Following your suggestion, I've changed the log-in user to of both service for the same user as my client application and with that configuration, both service successfully start after a connection attempt. From that test, I conclude from that the problem is more at the Access permissions than Lauch permissions. As before, once connected I'm able to excute read/write queries to the Matrikon server and I received an access is Denied error for the AXS4ICCP server.
Thanks.

Please Log in or Create an account to join the conversation.

More
14 Jan 2013 18:09 #1170 by support
Replied by support on topic Re: Access is denied error
Thank you.
1. Do you "pre-start" the service, or does is it started by first OPC client connected to it? If you don't start the service upfront, does connection attempt from your application at least start the service, or is the service still stopped? (Reason for this questions: There are two sets of permissions, Launch permissions and Access permissions. I am trying to determine which ones are causing the problem at first).
2. Have you tried to run the service under the same account as the Matrikon OPC server is running (or are you already doing it that way)? I understand that this may not be the best setup for production, and I also understand that other clients can connect to the service already, but I think it is a setup worth experimenting with, to gain a but more knowledge.
Kind regards,
ZZ

Please Log in or Create an account to join the conversation.

More
14 Jan 2013 16:52 #1169 by gmessoroch
None of the call to BrowseBranches, BrowseNodes or BrowseLeaves are successfull. They all return the same "access denied" error. However a BrowseServers call is successfull and I can see the AXS4ICCP server in the results.
Yes, the Authenticafication Level in DCOMCNFG properties for the AXS4ICCP server is connect.
The DCOM setting for both the Matrikon and AXS4ICCP server are identical. The only discrepencies I see between both is the fact that there is two entries for AXS4ICCP server in DCOM setting. One for when the OPC is running as a service (my case) and a second one when it's running in a standalone mode.
Both OPC servers are on the same remote host, therefore they share the same server DCOM config (My computer - properties in DCOMCNFG).
Thanks

Please Log in or Create an account to join the conversation.

More
13 Jan 2013 14:30 #1167 by support
Replied by support on topic Re: Access is denied error
Hello.
Sometimes there are problems similar to yours, and they are difficult to resolve because we never managed to reproduce the same on our side.
This said, here are some questions and options:
- Can you please test whether BrowseLeaves, BrowseBranches or BrowseNodes call works? (the reason I am asking is because there some internal difference from how Reads and Writes work). Or, is there *anything* that works for that particular remote OPC server, or do all operations you have tried result in "Access denied"?
- What is the Authentication Level in DCOMCNFG properties for AXS4ICCP server (on the General tab)? If it is not Connect, have you tested with setting it to Connect?
- Have you truly compared the DCOM settings (in DCOMCNFG) for the Matrikon OPC server (that works) and AXS4ICCP (which doesn't) to every little detail? On the General tab, is the Authentication level the same? Is the information on Identity tab the same? Is the information on the Security tab the same, including the precise access control lists for any setting that is set to Custom?
- If the Matrikon OPC Server is on a different machine from where the AXS4ICCP server is, are the DCOM default on these two machines precisely the same? (right-click on the "My Computer" node in DCOMCNFG, select Properties). Is the information on the "Default Properties" tab same on both computers? Are the user accounts under the 4 options on the "COM Security" tab same on both computers?
Best regards,
Zbynek Zahradnik

Please Log in or Create an account to join the conversation.

More
11 Jan 2013 19:46 #1164 by gmessoroch
Thank you Zybnek for your reply.
The problem I'm experiencing is with a simple Win Form application making direct calls to a remote OPC server, so I'm executing the executable from my own account, inside VS2010 or as standalone program.
The facts that:
1) The exact same code is able to execute remote access to another type of OPC server ( Matrikon's OPC server)
2) The code modified with another OPC access library ( Kepware) to the remote AXS4ICCP server
both works perfectly, tend to prove that it's not a DCOM related issue. The only issue I'm having is with the exact combinaison of OPC Labs + remote access to AXS4ICCP OPC (It also work when the OPC server is local).
Any others suggestions?

Please Log in or Create an account to join the conversation.

More
11 Jan 2013 19:29 #1161 by kasssa
Replied by kasssa on topic Re: Access is denied error
You may be under the mistaken impression that I am part of OPC Labs - that is NOT correct. I am a user of an OPC Labs product, just like you!
My intent was to try and be helpful, not to say anything to discourage you. My apologies if I did or said anything to lead you to think that I was part of OPC Labs. I'm just another member of the user community. In other groups that I belong to, we try to help each other. Maybe that is not how OPC Labs forums operate...
So maybe you should wait until somebody from OPC Labs answers your question. You can identify them by "OPC Labs" appearing in their name!

Please Log in or Create an account to join the conversation.

More
11 Jan 2013 19:16 #1159 by support
Replied by support on topic Re: Access is denied error
Hello.
Your client code that uses QuickOPC is running in aWindows service, correct?
If so, what is the user account the client service is running under? Have you tried - just for the test - set the service to run under your account (the interactive account that you use when you run the UI-based clients that work...)? If switching the service account in this way helps, we will know for sure that you just need to tweak DCOM and the accounts/permissions again.
Zbynek Zahradnik

Please Log in or Create an account to join the conversation.

More
11 Jan 2013 18:59 #1157 by support
Replied by support on topic Re: Access is denied error
I'd like to clarify that responses from user 'kasssa' are welcome, but are not from OPC Labs technical support.
I will post our reply soon.
Zbynek Zahradnik

Please Log in or Create an account to join the conversation.

Moderators: support
Time to create page: 0.107 seconds