What is OPC-DA?

OPC-DA stands for Open Platform Communications Data Access – this is a communications protocol used for accessing process data. OPC-DA was released in 1995 and since then has become extremely well known; popular to the point that these days, most SCADA system providers will support OPC-DA.

OPC-DA will retrieve data from a device while also providing a VQT (value, quality and timestamp), but it is worth mentioning the dated nature of OPC-DA means that it is not OS agnostic – and is in fact, almost exclusively a windows product.

What's the difference between OPC-DA and OPC-UA?

OPC-DA comes under the OPC Classic model. OPC Classic uses DCOM communication for Client-Server connection. DCOM is for Windows OS. And, DCOM and RPC ports aren’t as engineer-friendly.

OPC-UA does not rely on DCOM communication and is operating system (OS) agnostic. As well as this OPC-UA has many more attributes/properties that can be shared between client and server. 

For these reasons it is recommended that when a choice is available, OPC-UA is the better option.


 OPC-DA, is an older version of OPC specification. It was built without security and firewalls in mind and has problems with authentication and security.

OPC-DA to MQTT adapter

The ability to take OPC-DA messages and transcribe them to MQTT is extremely useful because typically, these two communications protocols will not communicate with each other. OPC-DA will gather VQT data and pass that along. MQTT on the other hand is preferred by developers due to its ease of use, speed and user-friendliness.

For this reason MQTT is a standard protocol for our solutions, which is why we have created these easy protocol adapters for OPC-UABACnet and more.

To learn more and understand how our solution can fit into your system. Please get in touch with our team.

If you have any suggestions for improvements please tell us – Contact Us

Ready to get started with Asset Monitoring?