Where Does OPC Expert Run When Connecting OPC UA to OPC DA?

When using OPC Expert to bridge an OPC UA client to an OPC DA server, does it run on the client machine or the server machine?

OPC Expert can run on any machine in your network and does not need to be installed on either the OPC UA client machine or the OPC DA server machine specifically. It acts as an intermediary that connects to both endpoints from wherever it is deployed. In practice, it is often placed on a dedicated machine or on one of the existing machines in the communication path, depending on network topology and access requirements.

OPC Expert as an Intermediary Client

When OPC Expert bridges an OPC UA client to an OPC DA server, it functions as an OPC client to the OPC DA server while simultaneously presenting itself as an OPC UA server to the OPC UA client application. This means your OPC UA client connects to OPC Expert as if it were connecting to a native OPC UA server, while OPC Expert handles the communication with the underlying OPC DA server on its behalf. The protocol conversion happens transparently within OPC Expert.

Placement Flexibility

Because OPC Expert requires no installation and does not modify the Windows Registry, it can be run from a USB drive or copied to any Windows machine without concern about altering system configurations. You can place it on the machine running the OPC DA server, on the machine running the OPC UA client, or on a third machine that has network access to both. Local and remote OPC server connections are both fully supported, so placement is driven by what is most practical in your network environment rather than by software restrictions.

Tunneling for Remote Scenarios

When the OPC DA server and the OPC UA client are on separate network segments, OPC Expert’s built-in tunneling capability handles the secure cross-network communication automatically. This removes the need for DCOM configuration between machines, which is one of the most common sources of complexity in traditional OPC Classic remote setups. OPC Expert manages the connection and handles firewall traversal, making the distance between the two endpoints largely transparent to the operator.

Relevant Tools

OPC Bridge handles the data transfer and protocol conversion between OPC DA and OPC UA servers as a feature of OPC Expert. OPC Tunneler is the module that manages secure communication across network segments, eliminating DCOM dependencies for remote connections. Together, these two capabilities allow OPC Expert to act as a flexible middle layer regardless of where in the network it is physically deployed.

OPC Expert’s deployment flexibility is one of its practical advantages in mixed-protocol environments. By functioning as both an OPC client and an OPC server simultaneously, it can sit anywhere in the network path and still provide seamless connectivity between OPC UA and OPC DA endpoints.