Form Set Variable Fields
Variable fields which exist in the form set can be used in the source expression. Variable field names which are used in the source expression must be written in a particular format. The name must be enclosed in quotes. Here is an example:
$SubTotal = sum ("Amount")
In this example, the sum of the all section fields that have names starting with Amount are subtotaled. The result is stored in the decimal target variable named $SubTotal. Form set field names are not case sensitive.
Using a particular field name
If you want to use a particular field name, the name must appear in this format:
Be sure to include the parentheses and the quotation marks.