Discovery is a special procedure that a Niagara AX installation technician follows to add driver device components and control point components to his or her Niagara AX station. When configuring stations to use your driver, Niagara AX installation technicians will double-click the drivers folder below the config folder in the station. Then the technicians will click the New button and choose your driver's network from the drop down list box on the window that appears.
After that, technicians will double click your network to visit your driver's device manager. By using the developer driver framework, you can automatically provide a fully-functional device manager when the technician double-clicks your network. After that, technicians prefer to click the Discover button from your driver's Device Manager. After clicking the Discover button, the station performs special communication on your field-bus and figures out which devices are online. Then Niagara updates the top half of the Device Manager with a list of available devices. Technicians will then select one or more devices from the top half and click the Add button. That adds one of your driver's device components for each of the selected items.
If you follow the steps in today's lesson and update your driver accordingly, then the developer driver framework on which your driver is built, will automatically perform all details for the device discovery process.
In the previous day's lessons, you programmed your driver to ping a field-device in order to determine whether it is online. You also programmed your driver to read and to write data values in your equipment using Niagara AX control points.
To ping your field-device, you created a device component, a device id structure, and a ping request. In Java code you made some special associations between these. That allowed the developer driver framework to do the rest.
Similarly, to read and write data values from your field-device, you created a proxy extension component, a read parameters structure, a write parameters structure, a point id structure, a read request, a read response, a write request, a write response, and possibly a point-auto request and a point-auto response. In your Java code, you made some special associations between these. That allowed the developer driver framework to do the rest.
The process of adding support to your driver for auto-discovery of devices will be rather similar.
Copyright © 2000-2016 Tridium Inc. All rights reserved.