A Variable Group event trigger executes
when the data value of any device variable in a variable
group meets a defined condition.
You must have a variable group defined in order to use this
event. For more information, see Defining, viewing, and controlling variable
groups.
Defining a variable group event trigger
To define a variable group event trigger, follow these steps:
- From the Workbench left pane, expand the node where
you want to define the variable group event
trigger.
- Select the Project icon to display
the Projects window, right-click a
specific project tab to display its pop-up menu, and
then select New.
You also can select the New button at the bottom of the Projects window when a specific project tab has already been selected. - The new Trigger window
appears.
Name the trigger. The trigger name can be up to 64 characters and include letters, numbers, and the underscore character. Spaces are allowed. - From the Event tab, select the
Trigger Event Type down-arrow, and
then select Variable Group.
The Event tab becomes active with parameters that accommodate the variable group event.
| Parameter | Description |
|---|---|
| Variable Group Name | A list of variable groups. A variable group is created using the Variable Groups tab. |
| Condition | Currently, there is only the Value changed condition. When any of the variables' value within the variable group changes from its previous value, the trigger will execute. In order for the trigger to execute, the variable group selected must be in a Started state. |
Variable group event type trigger event variables
The input event variables available to a variable group event trigger are:
| Event variable | Data type | Description |
|---|---|---|
| DATA | The data type of the device variable | The data value from the device variable. |
| Device Name | STRING | The name of the device where the device variable resides. |
| Variable Group Name | STRING | The name of the variable group. |
| Variable Key | STRING | The key associated with the device variable, when the device variable was added to the variable group. This variable key can be used as a reference ID, or correlation ID, to help identify which variable's value in the group has changed. |
| Variable Name | STRING | The name of the device variable. |