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A time expression is a numeric expression followed optionally by a time unit (WK, DAY, HR, MIN, SEC) which defines a duration. If no time unit is specified, the default time unit specified in the General Information dialog box is assumed. ProModel knows whether an expression is a time expression based on the context. Time expressions are not valid within a function call. For example, E(10 sec) is invalid, while E(10) sec is valid. If a negative value is used for a time expression, it is automatically converted to zero.
Syntax for time expressions
<numeric expression>{<time units>}
2 hr
E(10) min
Var1+40.25 min
Note that time units cannot be mixed (e.g., 3 min 21 sec), unless you use colon notation.