Detailed description
2.14 Programming tips with STEP 7
Basic logic functions: PLC basic program solution line (P3 sl)
262 Function Manual, 11/2006, 6FC5397-0BP10-2BA0
FUNCTION FC 99: VOID Comment
BEGIN
NETWORK
TITLE =
L
P##Addr;
LAR1 ;
//Retrieve pointer from Addr
L
D [AR1,P#2.0]; //Offset part of pointer of variable
LAR1 ;
END_FUNCTION
2.14.7 Calling function blocks (FBs)
General
For optimizing the flow speeds, it is useful to call all function block calls with many static
parameters, such as the blocks FB 2, FB 3, FB 4, FB 5, FB 7 provided by the basic program,
in start-up itself with the related instance parameters. In the start-up (OB 100), the
preassignment of the parameters must be done, which can then no longer be changed in the
cyclic part (OB 1). These fixed parameter values are no longer parameterized in the cyclic
call, because they have already been written in the Instance DB.
Example of parameterization of FB 2 with instance DB 110
The following example shows how a useful distribution in OB 100 and OB 1 portion is to be
implemented. first, the usual call in the cyclic program is displayed.
CALL FB 2, DB 110 (
Req := M 100.0,
NumVar := 2, //Read 2 variables
Addr1 := NCVAR.C1_RP_rpa0_0
Line1 : W#16#1
Addr2 := NCVAR.C1_RP_rpa0_0
Line2 . W#16#2
Error := M1.0,
NDR := M1.1,
State := MW 2,
RD1 := P#M 4.0 REAL 1,
RD2 := P#M 24.0 REAL 1,