PLC Programming

IEC Operators and additional norm extending functions
Example in FBD:
Example in IL:
LD 16#45
SHL 2
ST
erg_byte
10.4 Selection Operators
All selection operations can also be performed with variables. For purposes of clarity we will limit our
examples to the following which use constants as operators.
SEL
Binary Selection.
OUT := SEL(G, IN0, IN1) means:
OUT := IN0 if G=FALSE;
OUT := IN1 if G=TRUE.
IN0, IN1 and OUT can be any type of variable, G must be BOOL. The result of the selection is IN0 if G
is FALSE, IN1 if G is TRUE.
Example in IL:
LD TRUE
SEL 3,4
ST Var1 (* Result ist 4 *)
LD FALSE
SEL 3,4
ST Var1 (* Result ist 3 *)
Example in ST:
Var1:=SEL(TRUE,3,4); (* Result is 4 *)
Example in FBD:
Note:
Note that an expression occurring ahead of IN1 or IN2 will not be processed if IN0 is TRUE.
MAX
Maximum function. Returns the greater of the two values.
OUT := MAX(IN0, IN1)
IN0, IN1 and OUT can be any type of variable.
Example in IL:
CoDeSys V2.3 10-9