In order to do this Access control must be set to “user level” first under the access control tab of network configuration. Go to Network Neighborhood and right click. Choose properties and go to the access control tab. Select “user level access control.” You must fill in a domain name in the text box. Enter the name of the domain from which you wish to allow users access. You will have to reboot at this point.
Next go to the start menu and choose run. Type in “DCOMCNFG” and click OK. Go to the Applications tab and choose the application you want to grant access to. Click the properties button and go to the Security tab. Choose “use custom access permissions” and click edit.
Click add and choose the domain from where you want to add users. Choose
“Everyone” from the list. This will grant all domain users DCOM access to this Windows 95 or 98 system.
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As an alternative, you may choose to add only specific users that you want to grant access to this PC.Next go to the default security tab and check the “Enable remote connection” check box. Finally, go to the Default Properties tab and check the “Enable Distributed COM on this computer” check box.
WIN NT
DCOM should install as part of Windows NT 4.0 or higher.
Since DCOM uses Windows NT security, there are several ways to enable a connection between two PCs.
Use the same login on both PCs. The simplest way is to log into both PCs using the same login. A domain login can be used like \\domain\username or if using workgroups a local account can be used like “username”.
Since using the same login on the server and client PCs may not be practical, there are several other ways to enable DCOM between two PCs. All of these methods require that a Primary Domain Controller exist on the network.
Allow some or all domain users privileges under DCOM Configuration.
Go to the start menu and choose run. Type in “DCOMCNFG” and click OK. Go to the Default Security tab and click the first “edit default” button (the one under the Default Access Permissions section). Click add and choose the domain from where you want to add users. Choose “Everyone” from the list. This will grant all domain users DCOM access to this Windows NT system.
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As an alternative, you may choose to add only specific users that you want to grant access to this PC.Finally, go to the Default Properties tab and check the “Enable Distributed COM on this computer” check box.
The above method allows users to access any COM enabled application on the PC. A more secure method is to grant users rights only to specific applications. This is also done through the DCOMCNFG application.
Allow some or all domain users privileges to a specific application only under DCOM configuration.
Go to the start menu and choose run. Type in “DCOMCNFG” and click OK. Go to the Applications tab and choose the application you want to grant access to. Click the properties button and go to the Security tab. Choose “use custom access permissions and click edit. ”. Click add and choose the domain from where you want to add users. Choose “Everyone” from the list. This will grant all domain users DCOM access to this Windows NT system.
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As an alternative, you may choose to add only specific users that you want to grant access to this PC.Finally, go to the Default Properties tab and check the “Enable Distributed COM on this computer” check box.
Configuring Rockwell Software for OPC over a network
No special configuration should be required for RSI servers built with the RSServer OPC Toolkit such as RSLinx or RSServers. You must have RSLinx 2.0 or higher to use OPC. See the help files of each specific RSServer to see if it supports OPC or call Rockwell Software. However, because Rockwell Software clients use local registry entries to find information about OPC servers, the server must be registered on both the client and server PCs.
The easiest way to do this is to install the server on all PCs involved, clients and
servers. Activation for the server does not have to be installed, since the server will not be run on the client machines, just the registry entries are required.
Another way to register the server is by using a “.REG” file. Double clicking on a file with the .REG extension will insert the contents of that file onto the PCs registry. This file may be available from the Rockwell Software, call for more information. The OPC foundation is considering standardizing the way a client might browse a server machine over the network for a list of available OPC servers. Such a standard would eliminate the need to register the server on the client PCs. Rockwell Software will implement this feature once the OPC foundation has agreed on a standard method.
Configuration of OPC via DCOM varies from client to client. RSView32 and RSTools will be covered here. See the help files of other RSI client product for instructions on configuring OPC or all Rockwell Software.
RSView32 version 6.0 or higher can be configured for OPC through the Node
Configuration. Under the Systems folder in the project dialog, choose “Node ”. Radio buttons on the top of the dialog will allow you to select Direct Driver, DDE or OPC as a node type. Choose OPC. Next move to the Name text box and enter a name for the station. It can be anything you want. Then move to the server text box, click browse. Select the OPC server you wish to connect to, RSLinx OPC Server for example. Below this text box select the “Remote” radio button. In the Server Computer Name or
Address text box enter the name of the server PC or click browse if you are on a domain and select the server PC. Finally, under Access Path type in the name of the DDE topic you wish to connect to in the server. The Access Path is the DDE topic. Note, that although you are entering a DDE topic name, RSView32 will communicate to the server via OPC, not DDE!
RSTools can connect to an OPC server by using a special syntax for the application name under the “Link” Tab. Right click on the RSTools Active X control and select properties. Go to the “Link” tab. Under application type in “OPC:\\Server PC Name/Server Name”, for example “OPC:\\Server\RSLinx OPC Server”. Enter the topic name as usual.
Note: You must have a version of tools that specifically supports OPC.