Use the ‎TIME_OF_DAY‎ keyword (‎TOD‎) to specify a time.

Syntax

<time keyword>#<time value>

<time keyword> : TIME_OF_DAY | time_of_day | TOD | tod
<time value> : <hour>:<minute>:<second>
<hour> : 0-23
<minute> : 0-59
<second> : 0.000-59.999

You can also specify fractions of a second. ‎TIME_OF_DAY‎ literals are treated internally as ‎DWORD‎ and the value is resolved in milliseconds.

PROGRAM POU
VAR
        todClockTime : TIME_OF_DAY :=  TIME_OF_DAY#15:36:30.123;
        todEarliest : TIME_OF_DAY := TIME_OF_DAY#0:0:0.000;
        todLatest : TOD := TOD#23:59:59.999;
END_VAR