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SUB_DT_DT
SUB_DT_DT subtracts a value of the data type DATE_AND_TIME from another DATE_AND_TIME
Description
value. The result is stored in the output variable of the data type TIME.
To add an enable input and enable output to the instruction, select [With EN/ENO] from the
"Instructions" pane (LD, FBD or IL editor). To reuse an instruction select "Recently used" from the
context menu or press <Ctrl>+<Shift>+<v> in the programming window.
PLC types
Availability of SUB_DT_DT (see page 1331)
The TIME result is only valid if the difference between the minuend and
subtrahend is smaller than or equal to the maximum TIME duration allowed.
Otherwise an overflow of the TIME result variable occurs and the CARRY flag is
set.
Data types
Data type
DATE_AND_TIME
DATE_AND_TIME
TIME
In this example the function has been programmed in ladder diagram (LD) and structured text (ST).
Example
POU header
All input and output variables used for programming this function have been declared in the POU
header.
LD
ST
When programming with structured text, enter the following:
TIME_result
Subtract date and time from date and time
I/O
Function
1st input
minuend
2nd input
subtrahend
output
result
:= SUB_DT_DT(DT_value1, DT_value2);
Date and time instructions
301
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