The element <validate> is used for validating the user entry thru an expression evaluation of the input information. The validation authenticates both numerical and non-numerical input.− Validating numerical user entry inputsThe numerical validation expression determines if the input value is in a specified number range. The expression uses standard numerical comparison operators (ie, equal, greaterThan, lessThanOrEqual) and connects the numerical comparisons with a Boolean connector (ie, or, and, exclusiveOr).An example is to validate that a pressure is entered in the range from 0 to 90 p.s.i. A state variable Pressure is used and the validation expression is given as [[Pressure >= 0] and [Pressure <= 90]]. A user entry that is < 0 or > 90 indicates an invalid value.− Validating non-numerical (character string) user entry inputsThe non-numerical validation expression can use various expression operators to determine the user entry length, included or excluded within a "set-string", or correct alpha or numerical text is entered in the correct sequence.An example is to validate that five characters are entered for a CAGE code. A state variable CAGEC is used and the validation expression is given as [sizeOf (CAGEC) = 5]. A user entry that is less or more than five characters indicates an invalid value.