Does OPC Expert Need to Be Installed on Both Machines?

Question: Does OPC Expert need to be installed on both machines involved in a bridge or tunnel connection, or only on one?

OPC Expert does not require installation at all, as it runs without modifying the Windows Registry or system settings. More importantly, for many connection scenarios you only need OPC Expert running on one machine. Whether a second instance is needed depends on the specific feature you are using and your network topology.

OPC Bridge: One Instance Is Sufficient

When using OPC Bridge to transfer data between two OPC servers, OPC Expert runs on a single machine and connects to both servers remotely over the network. It does not need to be present on the machines running those OPC servers. The bridge machine communicates with each server as an OPC client, reading from one and writing to the other. As long as the bridge machine has network access to both servers and the appropriate credentials, the connection works without placing OPC Expert on either server’s host machine.

OPC Tunneler: Half-Tunnel vs. Full-Tunnel

OPC Tunneler offers two configuration options. In a full-tunnel setup, one instance of OPC Expert runs on each side of the network boundary, creating a secure tunnel between the two. In a half-tunnel configuration, only one instance of OPC Expert is required on one side, while the other side connects to it using a standard OPC UA client. This reduces the deployment footprint when full access to both machines is not available or when simplicity is a priority.

No Installation Means Low Deployment Risk

Because OPC Expert does not require installation and does not change system settings, deploying it on a machine carries minimal risk. It can be run from a USB drive, a network share, or a local folder. This is particularly relevant in environments where software installation requires change management approvals, since OPC Expert can often be used without going through that process. When running as a Windows service for unattended operation, the setup is still handled without requiring a traditional installer.

Relevant Tools

OPC Bridge operates from a single machine and connects to remote OPC servers without requiring OPC Expert to be present on those servers. OPC Tunneler supports both half-tunnel (one instance) and full-tunnel (two instances) configurations depending on network requirements. The Troubleshooting OPC and DCOM module can run independently on any machine where an OPC connection problem needs to be diagnosed, without affecting the configuration of the machine it runs on.

In most bridging scenarios, a single instance of OPC Expert on one machine is all that is needed. The tunneling feature gives you additional flexibility if your network architecture requires a secure endpoint on each side of the connection.