Calls in ST

The following language elements can be called in ST:

Articles in this section:

Order for calling a language element

If you are calling one of these language elements but there are different language elements with the same name, the following order is applied:

  1. call of the method

  2. call of the function block instance – only if there is no method with the same name

  3. call of the function – only if there is no method and no function block instance with the same name

Here an explanation of this order using the example 1 where the following 3 language elements are declared:

  • one function block instance named Element1 (within the section VAR...END)

  • one method named Element1

  • one function named Element1

Due to the order for calling a language element, Neuron Power Engineer calls the methods. Neuron Power Engineer highlights parameters as faulty when they have not been declared within the method.

Example 1 for order when calling an element 
FUNCTION_BLOCK CallElement
  VAR
    Element1 : MyFB1;
  END_VAR
 
  METHOD PUBLIC Element1
  END_METHOD
 
  Element1(IN1:=1, IN2:=2); // The method "Element1" is called. 'IN1' and 'IN2' are highlighted as faulty. 
  Element1(IN1:=1);         // The method "Element1" is called. 'IN1' is highlighted as faulty.
  Element1();               // The method "Element1" is called.
END_FUNCTION_BLOCK
 
FUNCTION_BLOCK MyFB1
  VAR_INPUT
    IN1 : int;
    IN2 : int;
  END_VAR
  VAR_OUTPUT
    OUT1 : int;
  END_VAR
    
  OUT1 := IN1 + IN2 +2;
END_FUNCTION_BLOCK
 
FUNCTION Element1
  VAR_INPUT
    IN1 : int;
  END_VAR
  VAR_OUTPUT
    OUT1 : int;
  END_VAR
END_FUNCTION

If the declaration of the method is missing (see example2), Neuron Power Engineer calls the function block instance.

Example 2 for order when calling an element 
FUNCTION_BLOCK CallElement
  VAR
    Element1 : MyFB1;
  END_VAR
 
  Element1(IN1:=1, IN2:=2); // The function block instance "Element1" is called.
  Element1(IN1:=1);         // The function block instance "Element1" is called.
  Element1();               // The function block instance "Element1" is called.
END_FUNCTION_BLOCK
 
FUNCTION_BLOCK MyFB1
  VAR_INPUT
    IN1 : int;
    IN2 : int;
  END_VAR
  VAR_OUTPUT
    OUT1 : int;
  END_VAR
    
  OUT1 := IN1 + IN2 +2;
END_FUNCTION_BLOCK
 
FUNCTION Element1
  VAR_INPUT
    IN1 : int;
  END_VAR
  VAR_OUTPUT
    OUT1 : int;
  END_VAR
END_FUNCTION

Only, if the declaration of the function block instance is missing as well (see example 3), Neuron Power Engineer calls the function. Neuron Power Engineer highlights parameters as faulty when they have not been declared within the function.

Example 3 for order when calling an element 
FUNCTION_BLOCK CallElement
 
  Element1(IN1:=1, IN2:=2); // The function "Element1" is called. 'IN2' is highlighted as faulty. 
  Element1(IN1:=1);         // The function "Element1" is called.
  Element1();               // The function "Element1" is called.
END_FUNCTION_BLOCK
 
FUNCTION_BLOCK MyFB1
  VAR_INPUT
    IN1 : int;
    IN2 : int;
  END_VAR
  VAR_OUTPUT
    OUT1 : int;
  END_VAR
    
  OUT1 := IN1 + IN2 +2;
END_FUNCTION_BLOCK
 
FUNCTION Element1
  VAR_INPUT
    IN1 : int;
  END_VAR
  VAR_OUTPUT
    OUT1 : int;
  END_VAR
END_FUNCTION