An instance of this function block type encapsulates a text field which can be used to enter a value for a variable of an elementary or derived IEC 61131-3 type, i.e., a subtype of the generic type ANY . The data type name of the variable to be entered is specified by the TYPE input. An initial value to be displayed is specified by the IVAL input, and the value of the OUT variable is updated to the entered value upon an occurrence of an event at the REQ input, or upon completion of user data entry with the Enter key. The maximum number of characters displayable without overflowing the text field is specified by the W (width) input.

The operation of an instance of this type is described by the service sequences shown below.