Using the OPC DataHub's Web Server and ODBC scripting functionality, it is possible to send an SQL query from a web page to a database, and view the results in the page. The dbquery.asp demo page included in the latest OPC DataHub distribution gives an example of how this is done. With the OPC DataHub running on your local machine, you can view this page by typing localhost/dbquery.asp into your web browser:

You simply enter a DSN, user name, and password (if any) for the database, and an SQL query. When you press the Submit button, the page sends the query to the DataHub, which passes the query to the database, and returns the results, displaying them in the table on this page.

Logicpark GmbH, located in Thun, Switzerland, is a computer science engineering office specializing in consulting, training, software development, and project management, implementing extensive nationwide service packages. Logicpark applies the OPC DataHub to network machines and devices, to visualize and analyze process and machine data, and to meet the requirements of central data management.

"In all our years of experience with OPC integration, we find the OPC DataHub to be the best solution available," said Mr. Bruno Maurer, Solutions Leader for Logicpark. "It combines many capabilities in a single program and is much easier to configure than other popular products on the European market."

A chemicals producer in the United States is using the OPC DataHub and Cascade DataHub to access data from a proprietary PLC network. The PLCs are connected to a Linux computer running Cogent's Cascade DataHub for Linux.

The Cascade DataHub is connected to an OPC DataHub running in Windows. This architecture gives them access to the PLC data using standard OPC client software in Windows.