Date and time instructions
302
Part II IEC Instructions
SUB_DT_TIME
Subtracts time from date and 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_TIME (see page 1331)
Data type I/O Function
DATE_AND_TIME 1st input minuend
TIME 2nd input subtrahend
DATE_AND_TIME output result
Description
SUB_DT_TIME subtracts a value of the data type TIME from a value of the data type
DATE_AND_TIME. The result is stored in the output variable of the data type TIME_OF_DAY.
Data types
Example
In this example the function has been programmed in ladder diagram (LD) and structured text (ST).
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:
DT_result := SUB_DT_TIME(DT_value, TIME_value);