Technical data

Table Of Contents
IEC Functions
System Software for S7-300/400 System and Standard Functions - Volume 2/2
26-12
A5E00739858-01
Description FC23 LT_DT
The function FC23 compares the contents of two variables in the data type format
DATE_AND_TIME to find out if one is smaller than the other and outputs the result
of the comparison as a return value. The return value has the signal state “1" if the
time at parameter DT1 is smaller (less recent) than the time at parameter DT2. The
function does not report any errors.
Parameter Declaration Data Type Memory Area Description
DT1 INPUT DATE_AND_TIME D, L Input variable in format DT
DT2 INPUT DATE_AND_TIME D, L Input variable in format DT
RET_VAL OUTPUT BOOL I, Q, M, D, L Result of comparison
You can assign only a symbolically defined variable for the input parameters.
Description FC28 NE_DT
The function FC28 compares the contents of two variables in the data type format
DATE_AND_TIME to find out if they are unequal and outputs the result of the
comparison as a return value. The return value has the signal state “1" if the time
at parameter DT1 is not equal to the time at parameter DT2. The function does not
report any errors.
Parameter Declaration Data Type Memory Area Description
DT1 INPUT DATE_AND_TIME D, L Input variable in format DT
DT2 INPUT DATE_AND_TIME D, L Input variable in format DT
RET_VAL OUTPUT BOOL I, Q, M, D, L Result of comparison
You can assign only a symbolically defined variable for the input parameters.