The "properties" of an ActiveX object relate to the elements that define the object's functionality and appearance. The available properties for a selected ActiveX object are listed here, as defined by the object's creator.

The check box to the left of each item on the list indicates whether or not a tag has been associated with the Property. If the box is checked, it means an association has already been defined for the property. If you want to clear this tag association, simply uncheck the box, or clear the tag from the "Associate property with tag. . ." field.

You can create an association between an ActiveX object property and a variable tag so that changing values in one are reflected in the other. To create an association, you need to first choose a property from the property list. The label Associate property with tag will change to display the property name.

Select the variable tag you would like to associate with a property by clicking on the Wizard button and choosing from the list of available tags. Alternatively, the tag name can be typed in to the Associate property with tag field.

Note: You can only use variable tag names in this field. Functions, expressions and constants are not supported when defining ActiveX property tag associations.

You can only associate a property with a variable tag if the tag type is compatible with the property. To display a list of compatible tag types, select the property, and click List Property Types. A list of compatible data types will display, or a message will inform you that there are no compatible types.

If there are no types compatible with the property, the Associate Property with tag and Update association on fields will be disabled.

If you specify a tag which might be inappropriate for the selected ActiveX property, the Type Evaluation dialog will display an alert. This might happen if:

• The types compatible with the property are different from the tag type.
• The tag type is smaller than the types compatible with the property, meaning that data could be truncated or lost.

If an object property is "bindable", it means it can automatically send notification of value changes to Citect SCADA, and acknowledge any value changes from an associated tag. This means both the property and an associated tag will automatically update whenever the value for either changes.

If a property is not bindable, the property/tag association can only be synchronized according to the event selected in the Update association on Event field.

Be aware that if an object property is bindable, the Update association on Event field will be automatically set to <Property change notification> by default. You can change this setting if you want the tag association to be updated by a more specific event.

For properties that are not bindable, you can mimic the behavior of <property change notification> by selecting After update for the Update association on Event field.

This indicates the read/write status of the selected property. With ActiveX objects, some properties are read-only, whereas others accept value changes. If a property is marked "read only", it indicates that its value is fixed and can only be read by Citect SCADA. If its status is read/write, can modify the property during runtime via a tag association.

This defines when you want a value update to occur for the selected property and its associated tag. Use the menu to the right of the Event field to view events that can be used to trigger a tag association update.

The available events that can be used with a particular property are predefined by an object's creator. They typically include user interaction events (for example, mouse clicks), time events (such as a new day or new month), or value changes (such as "after update").