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.

Select a Base Template that provides a logical foundation for the device type. For example, valves, pumps, and motors that have multiple states based on discrete limit switches use the $DiscreteDevice base template. Pressure and level switches use the $Switch base template. Process variable transmitters and controllers use the $AnalogDevice base template. Finally, basic process data receivers use the $FieldReference base template.

A template is created either from a base template or from another derived template. Base templates are the objects provided with the Industrial Application Server. Base templates cannot be modified.

Never create instances directly from base templates, since you will not be able to take advantage of advanced configuration and maintenance capabilities. 

Four Object Editor tabs are used for configuring the template: The Object Information tab contains basic configuration information, object execution order, and a Help file link. The Script, UDA, and Extensions tabs are discussed in more detail in the following content.

After creating a derived template set, create sets of complex template instances. The derived templates become the basis for all other instances. This derivation practice is called containment.