Step 3.2. Set DCOMCNFG Settings for the CIMPLICITY OPC Server

Set DCOMCNFG setttings for the OPC Server on a Windows XP or Windows 2003 machine as follows.

Identity tab.

Security tab.

  1. Identity tab


The OPC server will take on the identity (and privileges and permissions) of the user account when activated by an OPC client. The chosen user account (either The interactive user or This user) must be authenticated on a remote OPC client node in order for some OPC interactions to occur (e.g. subscription notifications).

You must have identical user accounts with identical passwords on the OPC server and remote node in order for the remote node to connect with the server.

  1. Select the Identity tab in the CIMPLICITY HMI OPC Server Properties dialog box.

  2. Check either of the following.


The interactive user


This user

Important: Regardless of the method chosen, the account must be part of the USER group, at a minimum.


The interactive user

Checking The Interactive user does the following.


The OPC Server:

Is launched with access to the user interface.

Allows other interactive clients to attach to the server.


The server will shut down after a log out and data collection will be stopped. However, CIMPLICITY may still be running.

Use for

Tasks such as troubleshooting or initial setup


This user

Checking This user does the following.


User and Password fields are enabled.

Enter a valid User and Password.


Administrator account.

The current interactive user.

A special account set up for the OPC server.


The OPC Server

Runs as a background process, as if the entered user was logged in.

Allows other interactive clients to attach to the server and continues to run after log out; data collection continues.

Use for

Continuous activity.

Most often, the CIMPLICITY OPC Server is configured to run as a background process (i.e. non-interactive mode) with the OPC Server starting and stopping as OPC clients connect and disconnect.

  1. Security tab

  1. Select the Security tab in the CIMPLICITY HMI OPC Server Properties dialog box.

  2. Select Launch and Activation and Access  permissions for the interactive or selected user.

Consult Microsoft documentation for details about permissions options.

Note: Typically, check Use Default for Configuration Permissions.

  1. More information

Option 3.1. Windows XP/2003: Limit OPC Server instances.