LM small programmable controller software (based on CoDeSys) note 22: error 4268/4052

  I encountered this error when writing the program

Literally ：

4268： Wait expression

4052： The name is “   ” Of adh164 The block must be a declared example

 

Later, it was found that it was when calling this program block in this program , Didn't give this block a name , The name is empty. “  ”, So it prompts these two errors , Write a name on the program block , These two mistakes disappear . 

A function block is a POU, Itself has no return value , Output one or more values . Function blocks are declared with keywords

FUNCTION_BLOCK Start . In the figure in , use IL Write a function block FUB, There are two input variables and two inputs Outgoing variable . One of the outputs is the product of two inputs , The other output is the result of equal comparison .

To invoke a function block , The function block must be instance declared . For example, define a name as INSTANZ Of FUB Function block ,

The instance declaration is as follows ：

INSTANZ：FUB;

Examples are for function blocks , Each function block instance is an independent 、 Active objects that can complete specific logical functions . No

Same procedure 、 Different tasks can define and call application instances of function blocks , Each call instance occupies independent memory , Protect

Leave an independent logical state . Call function blocks by defining instances .

Only the input and output parameters of the function block can be changed from the outside . Direct assignment to internal variables of function blocks is not allowed . Function block instance name

It can be used as the input of function or function block .

Call of function block , Only change the value in the function block instance , The result only works when the same instance is called . By input “ real

Case name . Variable name ”, Call variables in the function block .

In text language IL and ST in , You can add parentheses after the function block instance name , Set the initial value of the input parameter . Harmony change

It is the same as initialization , Assignment uses symbols “:=”.

about SFC Language , Function block calls can only occur in single step mode .

After the function block is executed , All values remain unchanged until the next execution . Because there are intermediate variables in the function block , send

Seemingly the same input parameters may actually output different output values .

 

Error analysis of Hollysys programming software .doc