PLC Programming

Appendix D: CoDeSys Libraries
If the upper limit HIGH is exceeded by IN, O becomes TRUE, and when IN is below LOW, U becomes
TRUE. IL is TRUE if IN lies between LOW and HIGH.
Example in FBD: Result:
10.18 AnalyzationNew.lib library
This library provides modules for the analysis of expressions. If a composed expression is FALSE,
those of its components can be evaluated which are adding to this result.
In the SFC-Editor the flag SFCErrorAnalyzationTable (see chapter 2.2.3) uses this function
implicitely for the analysis of expressions in transitions.
Example of an expression:
b OR NOT(y < x) OR NOT (NOT d AND e)
The functions:
The following variables are used by all modules:
InputExpr: BOOL, expression to be analysed
DoAnalyze: BOOL, TRUE starts analysis
ExpResult: BOOL, current value of the expression
Different for the particular analyse modules is the output of the result of the analyzation:
1. AnalyzeExpression returns in a string the components of the expression, which are adding to the
total value FALSE. Function AppendErrorString is used for this purpose, separating the particular
components in the output string by "|" characters.
OutString: STRING, Result of the analysis, Sequence of the concerned components of the
expression (e.g. y < x | d)
2. AnalyseExpressionTable writes the components of the expression, which are adding to the total
value FALSE, to an array. For each component the following information is provided by structure
ExpressionResult: name, address, comment, (current)value.
OutTable: ARRAY [0..15] OF ExpressionResult;
e.g.
3. AnalyseExpressionCombined combines the functionalities of AnalyzeExpression plus
AnalyseExpressionTable.
CoDeSys V2.3 10-59