Do OPC Expert and Excel Need to Be on the Same Computer as the OPC Server?

OPC Expert and Excel do not need to be on the same computer as the OPC server. OPC Expert connects to both local and remote OPC servers, and this remote connectivity is demonstrated explicitly in the OPC to Excel webinar. The OPC server can reside on a separate machine on the same network, a remote machine accessed over TCP/IP or HTTP, or in some configurations directly on the PLC or controller itself if that device supports OPC UA.

Remote Connectivity Using OPC UA and OPC Classic

When connecting to a remote OPC UA server, OPC Expert uses the server’s configured endpoint URL over TCP, which is firewall-friendly and straightforward to configure. No special infrastructure beyond network access to the server’s OPC UA port is required. When connecting to a remote OPC Classic DA server, communication uses DCOM, which requires proper DCOM configuration on both the client and server machines, including user account permissions and firewall rules for the relevant ports. OPC Expert’s troubleshooting module provides step-by-step guidance for resolving remote DCOM connectivity issues.

Where OPC Expert Runs Relative to Excel

OPC Expert and Excel do need to be on the same Windows machine as each other, because the integration between OPC Expert and Excel uses Microsoft’s Real-Time Data server mechanism, which operates within the same Windows session. OPC Expert acts as the RTD server and Excel acts as the RTD client on that machine. The OPC servers that supply the data can be anywhere on the network. In other words, the architecture places OPC Expert and Excel together on a workstation, with OPC Expert reaching out to remote OPC servers on other machines.

Running Without a User Logged In

OPC Expert’s data collection and archiving components can run as Windows services, which means data is captured continuously even when no user is logged into the workstation. The Excel workbook can then be opened at any time and retrieve historical data that was archived while Excel was closed. This is shown in the webinar, where OPC Expert is closed entirely and Excel retrieves current historical data when reopened, because the archive service continued running in the background as a Windows service.

Relevant Tools

OPC to Excel is the OPC Expert module that bridges remote and local OPC servers with Microsoft Excel. It supports connections to OPC servers over TCP/IP and HTTP and works with both OPC DA and OPC UA protocols regardless of where those servers are deployed on the network.

Troubleshooting OPC and DCOM is the OPC Expert module that provides guided diagnostics for remote OPC Classic connectivity issues, including DCOM configuration errors, firewall blocks, and authentication problems that commonly arise when the client and server are on separate machines.

Summary

OPC Expert and Excel reside on the same workstation, but the OPC servers they connect to can be on any network-accessible machine. Remote OPC UA connections are straightforward over TCP. Remote OPC Classic connections require standard DCOM configuration. The archiving component runs as a Windows service so that data collection continues independently of whether Excel or the OPC Expert interface is open.