PLC Programming

Appendix B: Operands in CoDeSys
%QB7 Output byte 7
%MD48
%IW2.5.7.1
Double word in memory position 48 in the memory location.
depending on the PLC Configuration
The current PLC Configuration for the program determines whether or not an address is valid.
Note:
Boolean values will be allocated bytewise, if no explicit single-bit address is specified. Example: A
change in the value of varbool1 AT %QW0 affects the range from QX0.0 to QX0.7.
Memory location
You can use any supported size to access the memory location.
For example, the address %MD48 would address bytes numbers 192, 193, 194, and 195 in the
memory location area (48 * 4 = 192). The number of the first byte is 0.
You can access words, bytes and even bits in the same way: the address %MX5.0 allows you to
access the first bit in the fifth word (Bits are generally saved wordwise).
10.13 Functions
In ST a function call can also appear as an operand.
Example:
Result := Fct(7) + 3;
TIME()-Function
This function returns the time (based on milliseconds) which has been passed since the system was
started.
The data type is TIME.
Example in IL:
TIME
ST systime (* Result e.g.: T#35m11s342ms *)
Example in ST:
systime:=TIME();
Example in FUP:
CoDeSys V2.3 10-29