Declaration of input variables in ST

Syntax

Syntax
`VAR_INPUT (* optional_begin ) RETAIN NON_RETAIN ( optional_end )` `name_1, name_2, ..., name_n : data-type := initial-value;` `name_3, name_4, ..., name_n : STRING[length] := 'initial-value';` `name_5, name_6, ..., name_n : ARRAY [x..y] OF data-type := [initial-value_1, initial-value_2, .., initial-value_n];` `name_7, name_8, ..., name_n : ARRAY [x1..y1, x2..y2, x3..y3] OF data-type; ( Here, initial values are possible as well. )` `name_9, name_10, ..., name_n : REF_TO type := REF(name_A);` `( Additional pieces of data, such as partial addresses, are also possible for the variables. )` `( Note: If a function block type is used as type for the variable, it is actually a function block instance. *)` `END_VAR`

VAR_INPUT (* optional_begin *) RETAIN NON_RETAIN (* optional_end *)

  name_1, name_2, ..., name_n  : data-type := initial-value;

  name_3, name_4, ..., name_n  : STRING[length] := 'initial-value';

  name_5, name_6, ..., name_n  : ARRAY [x..y] OF data-type := [initial-value_1, initial-value_2, .., initial-value_n];

  name_7, name_8, ..., name_n  : ARRAY [x1..y1, x2..y2, x3..y3] OF data-type;  (* Here, initial values are possible as well. *)

  name_9, name_10, ..., name_n : REF_TO type := REF(name_A);

(* Additional pieces of data, such as partial addresses, are also possible for the variables. *)

(* Note: If a function block type is used as type for the variable, it is actually a function block instance. *)

END_VAR

Meaning

Meaning
Declaration of one or more →input variables, `name_1`, `name_2` etc. must be →IEC-identifiers. The declaration of more sections of this kind is allowed. The declaration is possible within declaration of a →program, of a →function block, of a →function or of a →method. Providing the optional keyword `RETAIN` or `NON_RETAIN` makes all elements of this section →retentive or non-retentive. `RETAIN` or `NON_RETAIN` is possible within the declaration of a program and the declaration of a function block. If variables are declared based on a structured data type within the section with `RETAIN` or `NON_RETAIN`, its structure elements (incl. nestings) are treated as retentive or non-retentive alike. A →data type is possible as type for a variable. See "Supported data types" to learn which data types are supported for the declaration of variables. Use the optional →initial value [`:= initial-value]` to assign a value to the variable (see "Initialization of variables in ST" for details). Moreover, it is possible to declare: `STRING` variables; details: see "Declaration of STRING variables (incl. access)" array variables – this is similar to the declaration of an array data type reference variables; details: see "Declaration of reference variables (incl. assignments to them)" The declaration of input `EN` is not necessary. See "Execution control: EN, ENO" for information on input `EN`.

Declaration of one or more →input variables, name_1, name_2 etc. must be →IEC-identifiers.
The declaration of more sections of this kind is allowed. The declaration is possible within declaration of a →program, of a →function block, of a →function or of a →method.

Providing the optional keyword RETAIN or NON_RETAIN makes all elements of this section →retentive or non-retentive. RETAIN or NON_RETAIN is possible within the declaration of a program and the declaration of a function block. If variables are declared based on a structured data type within the section with RETAIN or NON_RETAIN, its structure elements (incl. nestings) are treated as retentive or non-retentive alike.

A →data type is possible as type for a variable.

See "Supported data types" to learn which data types are supported for the declaration of variables. Use the optional →initial value [:= initial-value] to assign a value to the variable (see "Initialization of variables in ST" for details).
Moreover, it is possible to declare:

STRING variables; details: see "Declaration of STRING variables (incl. access)"
array variables – this is similar to the declaration of an array data type

reference variables; details: see "Declaration of reference variables (incl. assignments to them)"

The declaration of input EN is not necessary. See "Execution control: EN, ENO" for information on input EN.

Good to know

Good to know
Moreover, Neuron Power Engineer allows you to specify additional data for the declaration. See "Defining description, comment, JSON string or type for variables or data types" for details. Moreover, Neuron Power Engineer allows you to define a not yet fully specified location for the declaration. See "Declaration of a language element with partial address in ST" for details. Within a section `VAR_INPUT...END_VAR`, it is also possible to declare function block instances and to declare variables based on an interface.

(grey lightbulb) Moreover, Neuron Power Engineer allows you to specify additional data for the declaration. See "Defining description, comment, JSON string or type for variables or data types" for details.

(grey lightbulb) Moreover, Neuron Power Engineer allows you to define a not yet fully specified location for the declaration. See "Declaration of a language element with partial address in ST" for details.

(grey lightbulb) Within a section VAR_INPUT...END_VAR, it is also possible to declare function block instances and to declare variables based on an interface.

Example
`VAR_INPUT` `IN1, IN2 : INT;` `T1 : TIME;` `IN3: ARRAY [1..2] of BOOL;` `IN4 : STRING[10];` `myRefIN: REF_TO INT;` `END_VAR`