Configure DCOM for OPC DA connections

2 min

This document will detail the steps needed to configure DCOM access in Windows 7 and Windows 10. These settings are required for OPC DA (OPC Classic) connections between two PCs. You will need to configure different settings for the PC with the OPC server and the PC with the OPC client.

Step 1: Set up the Client PC

To set up the client PC:

Open Control Panel and set the view by option to Small icons.
Select Administrative Tools.
Open Component Services, then select Console Root > Component Services > Computers > My Computer.
Right-click My Computer and open Properties to open the popup window.
Open the Default Properties tab and set the Default Authentication Level to None.
Default Properties tab
Open the COM Security tab and select Edit Limits… in the Access Permissions section to open the popup window.
Allow Local Access and Remote Access for the ANONYMOUS LOGON group.
COM Security tab
Select OK on both popup windows to save your changes.
In Control Panel, open Windows Firewall.
In the left sidebar, select Allow a program of feature through Windows Firewall.
Select Change settings and select both options (Private and Public) on the File and Printer Sharing line.
Click OK to save your changes.
File and Printer Sharing option

Step 2: Set up the Server PC

To set up the server PC:

Open Control Panel and set the view by option to Small icons.
Select Administrative Tools.
Open Computer Management, then select Computer Management (Local) > System Tools > Local Users and Groups > Users.
In the menu bar, select Action > New User.
Add a username, password, and select the options “User cannot change password” and “Password never expires.” You may need to deselect “User must change password at next logon” to enable these options
Click Create, then click Close to finish creating the new user.
New user dialog box
On the Computer Management window, select the user you just created, then select Action > Properties.
Go to the Member Of tab, click Add… to open the Select Groups popup window, then click Advanced… to open another popup window.
Click Find Now to populate the Search results field, select the Administrators group, then click OK.
Click OK on the Select Groups popup window, then OK on the user Properties window.
Select Groups dialog box