Assigning a time stamp to expression

A mathematical expression in addition to the value specifies a time stamp. The value acquires this time stamp after the mathematic apparatus processes this expression.

The time stamp in the expression can be:

• defined
  • %NtV(Expression, Time)
  • %NvTV(Expression)
  • TIME
• undefined

If the time stamp is defined when evaluating the mathematical apparatus, it acquires the defined value.
If the time stamp is not defined when evaluating the mathematical apparatus, it acquires the time when the expression was evaluated.

As regards the periodic evaluation of the expression, the time stamp acquires the value of period (if the expression does not define the time stamp).