Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 130)

Chapter
Expressions, Variables and Operators 9
9 -20
You can change the fraction portion of TIME by manipulating the contents
of internal memory location 71 (47H). You can do this by using a
DBY(71) operator (page 9 -18). Note that each count in internal memory
location 71 (47H) represents 5 milliseconds of TIME.
>DBY(71) = 0 :REM FRACTION OF TIME = 0
>PRINT TIME
READY
>RUN
0
>NEW
>DBY(71) = 3 :REM FRACTION OF TIME = 3*5ms = 15 ms
>PRINT TIME
READY
>RUN
1.5 E-2
Only the integer portion of TIME changes when a value is assigned.
This allows you to generate accurate time intervals. For example, to create
an accurate 12-hour (43200 seconds) clock use an ONTIME statement
(page 11 -25). When the TIME interrupt occurs, the statement TIME 0 is
executed, but the millisecond counter is not re-assigned a value.
If interrupt latency exceeds 5 milliseconds, the clock remains accurate.
Commands
10
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