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COM_EXCEPTION: Access Denied

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20 Jan 2015 16:35 #2621 by support
Even though this is all local, you need to set DCOM permissions properly. This is because the application and the server are running in different processes. If you are using out-of-process ("Local Server") EasyOPC-COM, there is even a 3rd process (easyopcl.exe) in the middle that is also a COM component and needs to be configured.

Please have a look at various "DCOM for OPC" tutorials (e.g. www.opclabs.com/forum/com-connections/1345-dcom-for-opc-configuration-tutorial ).

Specifically, figure out under which account your PHP app is running (IIS app pool identity, most likely). Then, configure the OPC server (in DCOMCNFG) so that this (IIS) user can launch/access the OPC server.

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20 Jan 2015 15:27 #2620 by LordAshes
Recently we installed QuickOPC on a client (Windows 7) machine. We followed the Manual Application Deployment steps outlined in the COncept document except that we installed the necessary files (during the Production Installation step) for both NET and COM since we plan to use both (VS.NET applications and COM via PHP in IIS).

Both our NET and COM implementations are failing to obtain any data events from the server.

The error returned when we attempt to do a simple ReadItemValue request is as follows:

exception 'com_exception' with messages 'Source: OPCLabs.EasyDAClient.5.2 Description: Access is denied.' in 'C:\SPET\Modules\Support\test.php:6 Stack Trace: #0 C:\SPET\Modules\Support\test.php(6): com->ReadItemValue('','ICONICS.Simulat...','010017001103_40...')#1 {main}'


I briefly looked through the Concept document but it does not discuss any security settings that need to be set to enable EasyDAClient functionality.

The PHP page is being served on the same physical machine as the OPC Server (i.e. the read request is a local request not a remote request) and we have, temporarily, turned off the Windows firewall to ensure that it is not preventing the functionality.

Does anyone know what settings I should check to try to resolve this issue?

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