Tag association

Each property in the Database Exchange ActiveX control can be associated with a CitectSCADA tag, enabling data to be edited in the control and then downloaded directly to the tag.

Associations between tags and properties are configured in the Tag Association tab of the control's Properties dialog. Access the Properties dialog by double-clicking the ActiveX Control. The Tag Association tab includes the following fields:

Properties

The list of available properties. To select a property, click its checkbox.

Associate property with tag...

The CitectSCADA tag which the selected property will be associated with. Type in the name of the tag, or to choose from the list of defined tags, click the Insert Tag button.

Update association on

The event which causes tag values to update. To enable associated tag values to change as properties change, this must be set to DataDownloading. For descriptions of each event, see the full List of Events.

Property documentation

Most ActiveX objects come with some form of documentation to explain the object's controls and functionality. Some have a separate Help file included, others may have simple text prompts that briefly explain each property. Again, this depends entirely on what an object's creator has included.

The Property documentation field will display help information for a selected property, or will give appropriate instructions to obtain the Help required for a selected property. In most cases, the following message will appear:

"Click the '?' button to the right to display the Help topic for this property"

The button calls up the ActiveX object's Help file (if one is included), usually with the topic displayed that relates to the selected property. It should also provide information about the settings provided on any additional tabs the ActiveX object may call up on the properties dialog.

List Property Type

Lists the CitectSCADA types that are compatible with the selected property.

Clear Property

The Clear Property button clears the tag associations for ALL the ActiveX object properties. If you want to clear a tag association for a particular object property, you just need to uncheck the box to the left of the property.

If you accidentally click the Clear Property button, you can restore your tag associations by clicking Cancel and reopening the ActiveX properties dialog.

NOTE: For more information on Tag Association, see ActiveX: Associating Properties with Tags in the Citect help

You can associate tags and properties in three ways:

• Using the Tag Association tab on the Properties dialog.
• Manually, by implementing the DataDownloading event in Cicode.
• At runtime, using the ObjectAssociatePropertyWithTag Cicode function.

To create an association between a property and a CitectSCADA tag:

1. Double-click the Database Exchange ActiveX Control to access the Properties dialog.
2. Click the Tag Association tab along the right-hand side of the dialog, and the Appearance tab across the top.
3. Click the checkbox of a property in the Properties window to select it.
4. In the Associate Property with tag... field, specify a tag with which to associate the property. You can either type in the tag name, or use the Insert Tag button to the right of the field to choose from a list.
5. Select DataDownloading as the Update association on event. You must select this event to update the tags correctly. When a recipe is selected, the control will use data of the selected row to update all configured “column” properties and raise the DataDownloading event. When CitectSCADA catches this event, it will update all tags using values of their associated properties.
6. Click OK to apply the changes and close the dialog.

To create an association between a property and a CitectSCADA tag manually:

1. Implement the DataDownloading event handle in Cicode. Assume the control occupies “AN35” on graphics page “Recipe”. The event handle would look like this:

FUNCTION Recipe_AN35_DataDownloading(Object This)
STRING sValue;
sValue = _ObjectGetProperty(This,"Column001");
… your code here
END

2. As all “column” properties in the control are of the string type, you must manually convert their values to tags in the above code if a tag is not a string type. However, if Tag Association (see above) is used, CitectSCADA automatically converts values to tags at runtime when the tags are updated. A message alert notifies you if associated columns and tags are a different data type.

To create an association between a property and a CitectSCADA tag at runtime:

Implement the Cicode function ObjectAssociatePropertyWithTag using the following syntax:

ObjectAssociatePropertyWithTag(sObject,sPropertyName,sTagName,sOnChangeEvent)

Refer to the CitectSCADA on-line help for how to use this function.