Syntax
The syntax for data type parameter expressions differs from Tag and property references when using string values. Quotation marks must be used when referencing string parameters. The reason for this is that data type parameter references are replaced before any expressions are evaluated. This differs from Tag and property references seen elsewhere in ignition.
If the data type of the parameter is not a string, then quotation marks are not required, but can be used.
It does not matter if double quotation marks or single quotation marks (" versus ') are used as long as a matching closing quotation mark is present.
"{string parameter}" //This expression will evaluate successfully
'{string parameter}' //This expression will evaluate successfully as well |
Examples
Below is an instance of a Turbine UDT. It contains a string parameter named "turbine_location."

Inside the Turbine UDT is an expression Tag named Member Location. To show the value of the turbine_location parameter on Member Location, the following expression would be used on the UDT definition.

Omitting the quotation marks would result in an evaluation error.

The same syntax should be applied to parameters in bindings on alarm properties. Below is an example using the same UDT, but the expression is instead located on the Display Path property of an alarm.

Additionally, non-string parameters and static values can be included in the same quotation marks.
