Hi All, this is my first posting in the forum, please guide me if I missed some terms of use.

I have a problem to connect OPC Client to WinCC OPC Remote Server. The OPC Client successfully discovered the OPC Server on target computer, receive OPCEnum CLSID, and thats about it. When trying to connect (tested with multiple type of application), they give 80070005 Error (Access is denied).

This is what I have done:

1. DCOM Settings on both machine are set, "Everyone" & "Anonymous Logon" are also set, all access, write & read are given. Edit Defaults & Edit Limits are also set.
2. Connection test is OK, both machine can ping each other.
3. Username & Password for windows login in each machine is the same.
4. Firewall is off

These are some information that might help:

1. With Aspentech CIMIO as OPC Client, during creation of OPC DA Interface, it can discover the OPC Server name "WinCC.OPCServer" in target computer, along with AE, HDA, etc..
2. There is another ongoing OPC DA communication from this remote OPC Server to other OPC Client machine, using KepServer as client, It is running smoothly and data is transferred.
3. I also tested OPC Server status by using OPC Scout installed in OPC Server machine, result is OK.
4. OPCEnum service is running
5. I cannot find any WinCC service/process/application in Task Manager that act as OPC Server (strange!!) --> I want to make sure this service is permissible for the new OPC Client.

This is some specification detail:

1. WinCC as OPC Server. Server name is "OPCServer.WinCC". OPC Server installed in primary OS Server. In this system we have 2 OS Server (redundant), using PCS7 environment.
2. Windows Server 2016 Standard (OPC Server), Windows Server 2019 Datacenter (OPC Client).

I can only attach 1 file here, hope it helps.

Below is what I got from the client log file:

Thanks! We are really stuck on this.

Hello,

I try start with some help to go maybe further, not exactly OPC. In my case, I'll try set some PC app like TCP Server (Hyperterminal or Hercules) on that remote position and wait for Client other side connection, same PC app but as Client, simply prove connection from remote side can be established. Ping can be maybe ok but rules or other network restrictions can be not set. If your connection from one PC app Client will connect to that Server remote app ok and data you can pass as test, then probably problem can be with OPC system. Again, I recomemnd for first to be sure connection can be established as general TCP and then investigate further.

Dear,

Take a look at the following link:

Which DCOM settings must be checked for WinCC (V7 and Professional) with OPC DA if the connection between server and client does not work?https://support.industry.siemens.com/cs/nl/en/view/109768431 

Hopefully this will help you further.

Regards,

Cedric

Hi!

Thanks for your answer. I have checked & followed the full instruction on your link, but it is still not working for me with the same error code 0x80070005 Access is Denied (I tried all the steps with no failure, restart the machine, then test OPC again from Client).

This is a little bit confusing, something "unseen" must be happening here, or missed out.

I'm thinking of deactivating the other OPC-DA interface that is currently running on other client to this OPC server, and see if I can connect from this new Client

Hi,

I've got one more thought.

On your computer hosting the OPC server there is a Windows built in user group: "Distributed COM Users", here the user trying to access should als been added to.

To get here:

1. WIN+R
2. lusrmgr. msc
3. Groups >> Distributed COM Users
4. Add

If you find another solution, please let us know.

Regards,
Cedric

Hi Molthoff,

Really appreciate for you following up this issue. I did follow your suggestion to add the user to DCOM group. But afaik changes only apply after next user logon (I don't want to take the risk of putting HMI server down, even though I know its redundant).

I seem to have another alternative solution and it works : I tried doing same DCOM & Security configurations on the second HMI Server (standby server). The CIMIO discovered a similar OPC Server instance there with suffix '1' (OPC.Server.WinCC.1), and now connection is established on first try.

Im just wondering if this is caused by another OPC DA Client already connected to the primary HMI Server OPC..