Overview – Troubleshooting OPC Communications

View the appropriate sub section for resolving communication problems with OPC Servers.

Please note that for the most common communications to Modbus, Allen Bradley, and Siemens controllers Open Automation Software has built in communications that works at a higher speed than OPC Servers.
If you receive an RCW DLL Missing error install the OPC Foundation Core Components and restart the system. This will be a requirement if you have installed RS-Linx.
Use the OPC Foundation Sample Client to verify the OPC Server is working correctly.
If the OPC Foundation Sample Client works use the OPC Data Fix to connect to OPC Servers that do not run as a Windows Service.
If you are browsing RS-Linx OPC Server and you encounter a problem view the topic of RS-Linx OPC Server.
If only one OPC Client at a time can connect to the OPC Server set the OPC Server Identity with the DCOM Configurator to Interactive User.
View the DCOM Configuration Guide if the Windows Firewall is blocking DCOM access or the default DCOM security is not setup.
To connect to Remote OPC Servers install the OAS Service on the same computer as the OPC Servers.
Contact Open Automation Software at 1-303-679-0898 or send an email to support@oasiot.com if you have an OPC Server that you cannot connect to.