Figure 13 – Usage of function block input and output parameters (Rules)

1a)

Input read – inside function blocks

1b)

Input read – outside function blocks

Not allowed according to IEC-standard.
Possible enhancement in logi.CAD 3: →Input variables of →function block instances can be read outside of function blocks.

2a)

Input assignment – inside function blocks

Not allowed according to IEC-standard.

Possible enhancement in logi.CAD 3, if the corresponding rule is deactivated →Input variables can be written to inside of →function blocks.

2b)

Input assignment – outside function blocks

3a)

Output read – inside function blocks

3b)

Output read – outside function blocks

4a)

Output assignment – inside function block

4b)

Output assignment – outside function blocks

Not allowed according to IEC-standard.

Possible enhancement in logi.CAD 3, if the corresponding rule is deactivated →Output variables (= VAR_OUTPUT) of →function block instances can be written to outside of the function block.

5a)

In-out read – inside function block

5b)

In-out read – outside function blocks

Not allowed according to IEC-standard.

6a)

In-out assignment – inside function block

Allowed according to IEC-standard, note 3.

6b)

/

In-out assignment – outside function blocks

"Call with immediate parameter assignment" – allowed according to IEC-standard (if it is an expression which might be on the left side of the assignment operator := as well)
Possible enhancement inlogi.CAD 3 (for FBD), if the corresponding rule is deactivated : Connections (= lines) from an output of a →function block to a VAR_IN_OUT variable (= →in-out variable) are allowed.

"Separate assignment " – Not allowed according to IEC-standard.

attribute SIZE for directly derived data types

Declaration of a directly derived data type in ST

using named values of the appropriate data type for the array limits

Declaration of an ARRAY data type in ST

assigning the minimum value or maximum value of a data type in ST

How to assign the minimum or maximum value of a data type?

system blocks based on the →IEC-standard but with enhancements:

• bitstring functions: ROL , ROR , SHL, SHR

• convert functions: TO_BOOL, TO_BYTE, TO_DINT,
  TO_DWORD, TO_INT, TO_LINT, TO_LREAL, TO_LWORD,
  TO_REAL, TO_SINT, TO_UDINT, TO_UINT, TO_ULINT,
  TO_USINT, TO_WORD

• counter function blocks: CTD_UINT, CTU_UINT, CTUD_UINT

• numeric functions: EXPT

• select functions: MUX_BYTE, MUX_DINT, MUX_DWORD, MUX_INT, MUX_SINT, MUX_UDINT, MUX_UINT, MUX_USINT, MUX_WORD

• SHL block, SHR block,

• TO_BOOL block, TO_BYTE block, TO_DINT block,
  TO_DWORD block, TO_INT block, TO_LINT block,
  TO_LREAL block, TO_LWORD block, TO_REAL block,
  TO_SINT block, TO_UDINT block, TO_UINT block,
  TO_ULINT block, TO_USINT block, TO_WORD block

• CTD_UINT block, CTU_UINT block, CTUD_UINT block

• EXPT block

• MUX_BYTE block, MUX_DINT block, MUX_DWORD block, MUX_INT block, MUX_SINT block, MUX_UDINT block, MUX_UINT block, MUX_USINT block, MUX_WORD block

system blocks in addition to the →IEC-standard:

• enhanced bistable function blocks

• enhanced bitstring functions

• enhanced control function blocks

• enhanced convert functions

• enhanced numeric functions

• enhanced select functions

• enhanced timer function blocks

• enhanced memory functions

• BistableEnh function blocks

• BitstringEnh functions

• ControlEnh function blocks

• ConvertEnh functions

• NumericEnh functions

• SelectEnh blocks

• TimerEnh function blocks

• MemoryEnh functions

several variable sections VAR_GLOBAL...END_VAR within RESOURCE or CONFIGURATION

Declaration of global variables in ST

declaring global variables in a central object

Declaration of global variables in global-object and its usage in ST

write access to bit, byte, word or double word of an ANY_BIT variable

Partial access of ANY_BIT variables

• partial elements of in- and output variables within the call of a function block instance

• assignments of ENO of the block separately from the call of the block

Call of function block instance in ST

action qualifier PN

Action qualifiers for SFC elements

attribute OFFSET for partial addresses,
several variables with one partial address or several variables with partial addresses in one line

Declaration of a language element with partial address in ST

description, comment, JSON-string for variable or data type

Defining description, comment, JSON string or type for variables or data types

property statements

Property statement in ST

statement to suppress warnings

Statement to suppress warnings

statement to ignore ST-objects

Statement to ignore ST-objects

assignments from or to variables:

• →Input variables of →function block instances can be read outside of function blocks.

• →Output variables (= VAR_OUTPUT) of →function block instances can be written to outside of the function block.

• →Input variables can be written to inside of →function blocks.

• →Local variables (= VAR ) of →function blocks without a keyword for the visibility can be used inside the defining function block and its derived function blocks according to the standard. But it is possible to change the configuration so that these variables can be used anywhere where the function block can be used as well.

• Connections (= lines) from an output of a →function block to a VAR_IN_OUT variable (= →in-out variable) are allowed.

Figure 13 – Usage of function block input and output parameters (Rules) and/or
Rules for the validation of an application
and/or
Declaration of internal variables in ST and Declaration of function block instances in ST respectively

→References to local, temporary →variables can be used in →functions / →methods .

Rules for the validation of an application

parallel usage of SFC elements and FBD elements within the same POU

SFC elements in drawing field

behavior of negated inputs to which no other element is connected

Negating inputs and outputs

Other provided system blocks:

• target-system-depending blocks

• more system blocks

• Target-system-depending blocks for the application

• More system blocks

VAR_CONFIG section within resources and attribute SIZE within VAR_CONFIG sections

Declaring VAR_CONFIG sections within PLC-object

declaring VAR_CONFIG sections within a central object

Declaring VAR_CONFIG section within a VarCfg-object