OPC Server Machine Configuration

General Information

Domain Configuration

DCOM Configuration

Windows Firewall Configuration

General Information

• For remote OPC Server operation, server must be running under Windows XP Pro, Windows Server 2003, Windows Vista (Business & Ultimate), Windows 7 (Professional & Ultimate), Windows Server 2008.
   
• This document refers to Automated Solutions OPC Server throughout. If you are using Automated Solutions Modbus or Modbus/TCP OPC Server, simply substitute the appropriate file name:
  
  Automated Solutions OPC Server: Asopc.exe
  Modbus OPC Server: Asmbseropc.exe
  Modbus/TCP OPC Server: Asmbtcpopc.exe
   
• Two components require configuration in order to operate properly:
  • Automated Solutions OPC Server (Asopc.exe)
  • OPC Server Browser (OpcEnum.exe)
     
• Changes to Default DCOM settings could result in insufficient security for other DCOM enabled applications. Changes to default DCOM settings should be reviewed and approved by your system/security administrator.
   

Domain Configuration

If your PCs are members of the same domain

Proceed to section titled DCOM Configuration.

If your PCs are members of two different domains

When you have multiple domains, settings in both domains must be made so that Domain A trusts users from Domain B and vice versa.

For DCOM to work properly, trust must be established on both domain controllers. Refer to Microsoft Windows Server documentation for information on how to setup trusts between domains.

Once the trusts have been setup on your domain controllers, proceed to section titled DCOM Configuration.

If your PCs are not members of a domain

In the following section, Windows refers to Windows NT, 2000, XP, or Server 2003; Windows 9x and ME are not supported.

If your Windows PCs are not members of a domain, then they are running as standalone machines. Every Windows PC has it's own local database of trusted users regardless of whether it is a member of a domain. When a Windows PC is not a member of the domain, the ONLY user accounts it will trust are those it finds in its local security database.

If you attempt to connect to a remote server and are receiving an “Access Denied” or similar error, you are experiencing permission issues between the two PCs.

To alleviate the permission issue, all you need to do is create the EXACT SAME user account names AND passwords on BOTH PCs.

To verify proper permission settings, go to Network Neighborhood, browse from PC A to PC B and try to connect to PC B.

Once permissions are setup properly, you should proceed to section titled DCOM Configuration.

DCOM Configuration

Use these instructions to configure DCOM for OPC Servers running under Win XP, 2000, or NT 4.0.

OPC Server DCOM Configuration consists of three steps:

• Step 1: Configure Default DCOM Settings
• Step 2: Configure OPC Server DCOM Settings
• Step 3: Configure OPC Server Browser DCOM Setting

The dialogs shown in the configuration instructions are captured from a Windows XP system. For Windows NT and 2000, the steps are essentially the same, however the look and feel of the dialogs may be slightly different.

For Windows XP SP 2 or higher, you will need to perform the steps listed below and also refer to this OPC Foundation document for additional configuration instructions:

Using OPC via DCOM with XP SP2

When setting DCOM configuration and testing OPC Server for remote connectivity, it is recommended that Windows Firewall be temporarily disabled. After connectivity has been established, Windows Firewall should be re-enabled with exceptions to allow for OPC Server connectivity.

Step 1: Configure Default DCOM Settings

Run DCOM Configuration Tool

1. Open a Run prompt
    
2. In the ‘Open:’ list box, type in ‘dcomcnfg’
   
   
    
3. Click the [OK] button.
    
4. The next step is operating system specific.

Configure Default Properties Tab

1. Select the ‘Default Properties’ tab.
    
2. Select ‘Connect’ from the ‘Default Authentication Level’ dropdown list.
    
3. Select ‘Identify’ from the ‘Default Impersonation Level’ dropdown list.

Configure Default Protocols Tab

1. Select the ‘Default Protocols’ tab.
    
2. It is not necessary to make changes here for OPC, however, to minimize the DCOM timeout delay, you should move ‘Connection-oriented TCP/IP to the top and remove unused protocols.

Configure COM Security Tab

1. Select the ‘COM Security’ tab.
   
   
    
2. In the ‘Access Permissions’ section, click the ‘Edit Default’ button.
   
   Here you will set who will have access to OPC Servers and the OPC Server Browser on this machine.
    
3. Configure access permissions.
   
   To allow very broad access you could add the domain group ‘Everyone’.
   
   Or, if you would rather not allow access to Everyone, create a domain group and add all logins that will be allowed to access OPC Servers and the OPC Server Browser, then add the group to the ‘Group or user names’ list.
    
4. Configure for local and/or remote access.
   
   If remote OPC Clients will access the server, ensure that ‘SYSTEM’ is listed in the ‘Group or user names’ list box with the ‘Allow’ check box checked for ‘Local Access’ and ‘Remote Access’. If not, click the [Add] button, then add ‘SYSTEM’.
   
   If local OPC Clients will also access the server, also include ‘INTERACTIVE’.
   
   
    
5. Click the [OK] button.
    
6. In the ‘Launch Permissions’ section, click the ‘Edit Default’ button.
   
   Here you will set who can launch OPC Servers and the OPC Server Browser on this computer.
    
7. Configure launch permissions.
   
   To allow very broad access you could add the domain group ‘Everyone’.
   
   Or, if you would rather not give launch permission to Everyone, create a domain group and add all logins that will be allowed to launch OPC Servers and the OPC Server Browser, then add the group to the ‘Group or user names’ list.
    
8. Configure for local and/or remote Launch.

   If remote OPC Clients will be allowed to launch OPC Servers and the OPC Server Browser, ensure that ‘SYSTEM’ is listed in the ‘Group or user names’ list box with the ‘Allow’ check box checked for ‘Local Access’ and ‘Remote Access’. If not, click the [Add] button, then add ‘SYSTEM’.

   If local OPC Clients will also be allowed to launch OPC Servers and the OPC Server Browser, also include ‘INTERACTIVE’.

   

   9.Click the [OK] button.

    

Step 2: Configure OPC Server DCOM Settings

Open Automated Solutions OPC Server Properties

1. The next step is operating system specific.

Configure General Tab

1. Select the ‘General’ tab.
    
2. Select ‘Default’ from the ‘Authentication Level’ dropdown list.
   
   Authentication level will default to ‘Connect’ since we set the Default Authentication Level to ‘Connect’ earlier.
   
   

Configure Location Tab

1. Select the ‘Location’ tab.
    
2. Check the ‘Run application on this computer’ check box.
    
3. Uncheck all other check boxes

   

    

Configure Security Tab

1. Select the ‘Security’ tab.
    
2. For Launch Permissions we recommend that you check the ‘Use Default’ option.
   
   If you use the ‘Customize’ option, ensure that adequate OPC Server users and/or groups are added.
    
3. For Access Permissions, we recommend that you check the ‘Use Default’ option.
   
   If you use the ‘Customize’ option, ensure that adequate OPC Server users and/or groups are added.
    
4. For Configuration Permissions we recommend that you use the value that the dialog defaulted to.
   
   If you use the ‘Customize’ option, ensure that adequate OPC Server users and/or groups are added.
   
   

Configure Endpoints Tab

1. Select the ‘Endpoints’ tab.
    
2. It is not necessary to make changes here for OPC, however, to minimize the DCOM timeout delay, you should move ‘Connection-oriented TCP/IP to the top and remove unused protocols.
   
   

Configure Identity Tab

1. Select the ‘Identity’ tab.
    
2. The next entry depends on the intended operation of the OPC Server PC.
    

   'This user.' account Use this setting for unattended or attended operation ·  If there will not be anyone logged-on to the PC where the OPC Server is running, we recommend that you select the ‘This user’ option and specify a user name and password. This will allow the OPC Server to start with no one logged onto the PC. ·  You can also use this option if someone is logged on to the PC. ·  In the example shown to the right, the user name is ‘OPCServer’ and the user domain is ‘Domain1’. ·  If this option is selected and the server is started locally, the User account must have Admin privileges to make OPC Server configuration changes.
   'The interactive user.' Use this setting for attended operation ·  In general, we recommend using the ‘This user’ option discussed above. With this option, when a remote OPC Client launches the server, the server will not show up on your taskbar. ·  Alternately, if a user will always be logged-on to the PC where the OPC Server is running, you can select ‘The interactive user’ because there will be an interactive user under which to run the OPC Server. ·  If ‘The interactive user’ option is selected, when a remote OPC Client launches the server, the server will show up on your taskbar. ·  If either option is selected and the server is started locally, the logged-in user must have Admin privileges to make OPC Server configuration changes.
   'The launching user.' Do not use this setting.

3. Click the ‘OK’ button.

Step 3: Configure OPC Server Browser DCOM Settings

Follow the steps in Step 2: Configure OPC Server DCOM Settings, except substitute ‘OpcEnum’ for  ‘Automated Solutions OPC Server’

Windows XP SP2 and Higher Users Additional Settings

1. Refer to this document for additional settings required for Windows XP SP2 or higher
   
   Using OPC via DCOM with XP SP2
    

Windows Firewall Configuration

When setting DCOM configuration and testing OPC Server for remote connectivity, it is recommended that Windows Firewall be temporarily set to 'Off'. After connectivity has been established, Windows Firewall should be re-enabled with OPC-specific exceptions added to allow for OPC Server connectivity.

If Windows Firewall is permanently set to 'Off' on your system, you can skip this section.

Configuring Windows Firewall

Open Windows Firewall Application

1. Open Control Panel
    
2. Run 'Windows Firewall' applet.
   
   
    

Add OPC Server to Exceptions List

1. Select the 'Exceptions' tab
   
   
    
2. Click the [Add Program...] button.
    
3. The 'Add a Program' dialog will appear.
   
   
    
4. Select Automated Solutions OPC Server (Asopc.exe) from the list. If Automated Solutions OPC Server is not in the list, click the [Browse] button, browse to the Automated Solutions OPC Server install directory, and select Asopc.exe.
   
   Default install directory is C:\Program Files\Automated Solutions\OPC\ASOPC\.
    
5. Click the [OK] button.

Windows XP SP2 and Higher Users Additional Settings

1. Refer to this document for additional settings required for Windows XP SP2 or higher
   
   Using OPC via DCOM with XP SP2