ABB AC 800M, Руководство по стилю объекта библиотеки

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Section 6 Program Code Issues Conditional Range Check
3BSE042835-600 105
Conditional Range Check
Table 16. Parameter interface for an example type with conditional range check and last good value
Name
Data
type
Attributes Direction
Initial
value
Description
MyPar dint Retain In 1 Config (<=0 = Event1,
1 = Event2,
2 = Event3,
Else Last good value + ParErr)
EnablePar
Error bool Retain In false EDIT Enable par error
calculation for Non-SIL
applications.
ParError bool Retain Out Indicates parameter range
error.
If a conditional range check is applied, the execution time can be reduced in

Non-SIL applications.
In the example code, the parameter EnableParError is copied during the first scan
to a local variable EnParError for Non-SIL application, otherwise the local
variable will be true. If the range check finds an out-of-range value, the last good
value will be used.
if Init then
Init := false;
(* Force range checks if SIL application *)
EnParError := EnableParError or GetApplicationSIL() <> 0;
MyParInt:= MyLimit; (* Last good value *)
ParErrorInt := false;
end_if;
if EnParError then
(* Perform parameter range check each scan *)
(* before assignment *)
ParErrorInt := false;