Using the OPC DataHub it is now possible to display OPC data as a trend chart in a standard web browser, without using any plug-ins or special browser software. Using the AJAX web interface to display trend data allows the web page to be viewed in both desktop browsers and in web-enabled palm-top and hand-held devices. In this way, a plant engineer can carry a wireless hand-held device that displays trend data for the process as he walks around the plant floor. If a change is needed, he can enter new setpoints or make other changes directly from his hand-held device and then watch the change take effect, without having to return to a desk or workstation.