Create a template model

After generating and documenting field device requirements, decide on a template model that fits those requirements. Begin by reviewing the field devices and their requirements while looking for commonality across similar field device types. Determining this commonality is the basis for developing the template model. After you develop the template model, you can derive instances (run-time objects) from the templates. A template exists only as configuration-time object.

In most cases, you can use the $UserDefined template as the logical foundation for the device type. Other templates can also be used. For example, valves, pumps, and motors that have multiple states based on discrete limit switches can use the $DiscreteDevice base template. Process variable transmitters and controllers can use the $AnalogDevice base template.

The IDE includes a set of master templates in the _Default Templates folder as defaults. While these are writeable and can be configured, best practice is to create a derived template from these master copies, and configure the derived copy. A set of base templates, from which the master templates are derived is also provided. Base templates are read-only, and are located in the System folder. Never create instances directly from base templates, since you will not be able to take advantage of advanced configuration and maintenance capabilities.

Each template object contains three or more tabs when you open the template in the IDE Object Editor.

• The Object Information tab contains basic configuration and derivation information, object execution order, and a link to add a custom help file.

• The Attributes tab allows you to add unique, user-defined attributes. You can also configure an object wizard in the Attributes tab and link to graphics, scripts, and other content types, such as OMI layouts.

• The Scripts tab allows you add and configure scripts of different trigger types (Startup, Onscan, Offscan, Execute, and Shutdown) for the object.

Use the derived templates you build to create sets run-time instances. The derived templates become the basis for all other instances. This derivation practice is called containment. Note that changes made at the template level propagate to all objects that are derived from it, including instances and child templates.