P2039¶

Code: P2039
Message: Duration literal is outside the range the duration type can represent

This error occurs when a duration literal names a length of time the type cannot hold.

A duration is stored as a signed count of milliseconds, so the durations a program can write are the ones that count reaches:

Duration type ranges¶
Type	Storage	Range
TIME	32-bit milliseconds	`T#-24d20h31m23s648ms` to `T#24d20h31m23s647ms`
LTIME	64-bit milliseconds	about ±292 million years

The count is signed because a duration can be negative — subtracting one time from a later one gives a negative result.

A duration outside the range has no millisecond count to be stored as, so the compiler reports it rather than keeping the low bits, which would give a different duration than the one the program wrote — and often one with the opposite sign.

Example¶

The following code will generate error P2039:

Try it

Source

PROGRAM main
    VAR
        timeout : TIME := T#30d;
    END_VAR
END_PROGRAM

A TIME holds about 24.8 days, so 30 days is not a value it can take.

To fix this error, use a duration the type can hold:

Try it

Source

PROGRAM main
    VAR
        timeout : TIME := T#20d;
    END_VAR
END_PROGRAM

Or use LTIME, whose 64-bit count reaches far beyond any interval a control program is likely to measure:

Try it

Source

PROGRAM main
    VAR
        timeout : LTIME := LTIME#30d;
    END_VAR
END_PROGRAM

LTIME requires IEC 61131-3 Edition 3. See Edition Support.

Long intervals in a control program¶

A scan cycle is measured in milliseconds, so an interval of weeks is usually better counted than timed. Where a program needs to measure days or months, count elapsed cycles or completed days in an integer variable rather than holding the whole span in one TIME:

Try it

Source

PROGRAM main
    VAR
        day_elapsed : TIME := T#24h;
        days_run : UDINT;
    END_VAR
END_PROGRAM

This also keeps the value meaningful across a restart, which a running timer does not.

The literal names its own type¶

A duration literal is held to the range of the type its prefix names, not the range of the variable it is stored into. T#30d is out of range even in an LTIME variable, the same way INT#40000 is not an INT whatever it is assigned to:

Try it

Source

PROGRAM main
    VAR
        timeout : LTIME := T#30d;  (* Error: T# names a TIME *)
    END_VAR
END_PROGRAM

Write the prefix of the type you mean, as in LTIME#30d above.

Narrowing is reported too: an LTIME# literal does not fit a TIME variable, which is reported as P4022.

P2039¶

Example¶

Long intervals in a control program¶

The literal names its own type¶

See Also¶