• Templates

• A template is an entity that represents the common functional requirements of a field device (valves, pumps), a group of field devices (skids, stations), or a user function (algorithms). These requirements reflect information such as number of Inputs and Outputs, alarm conditions, history needs, and security. One object template performs the equivalent functions of multiple InTouch tags and scripts.

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

• Templates are high-level definitions of the devices in your environment. Templates are like a cookie cutter from which you can make many identical cookies.
• You define a template for an object, like a valve, one time and then use that template when you need to define another instance of that item. Template names have a dollar sign ($) as the first character of their name.
• A template can specify application logic, alarms, security, and historical data for an object.
• Wonderware Application Server comes with predefined templates, called base templates. You cannot change these templates. All templates you create are derived from base templates.
• You can also nest templates, or contain them. Contained templates consist of nested object templates that represent complex devices consisting of smaller, simpler devices, including valves. A reactor is a good candidate for containment.

• Instances

• Instances are the run-time objects created from templates in Wonderware Application Server. Instances are the specific things in your environment like processes, valves, conveyer belts, holding tanks, and sensors. Instances can get information from sensors on the real-world device or from application logic in Wonderware Application Server. Instances exist during run time.

• In your environment, you may have a few instances or several thousand. Many of these instances may be similar or identical, such as valves or holding tanks. Creating a new valve object from scratch when you have several thousand identical valves is time-consuming. That's where templates come in.

• Propagation

• If you need to change something about all diaphragm valves, you can change the template for the diaphragm valve and all diaphragm valves in your application inherit the changes, assuming the attributes are locked in the parent template. This makes it easy to maintain and update your application.

• Deriving a Template

• Templates are either derived from Base Objects, existing templates or created within the ObjectToolkit and imported.
• Base templates cannot have their attributes configured. However, a template can be derived from one of the base templates. That derived template can then be configured and customized for attributes unique to the object it is modeling. Once that derived template is configured, instances of it can be created. Each instance will have all the attributes of the derived template.