Support B&R .st

[bubkuh]

It seems to be incompatible with the code splitting of B&R libraries. B&R has separate files for variable declarations (*.fun) and source code (*.st) of functions and function blocks.

• it's always one *.fun file for all POUs per library
• a *.st file can contain the source code of any number of POUs
• several *.st files can also be created to separate POU implementations from each other
• Object-oriented features do not exist at all until today, therefore the location of these cannot be specified

Here's an example: https://github.com/tkucic/brOscatLib/tree/main/oscatBasic

[jubnzv]

Hi @bubkuh,

Thank you for the information, I hadn't heard about B&R before.

Do they have any documentation about the structure of the project? It also would be great to have the specification of the language they use, just to make sure, that we can support it. I'm asking this because there may be pitfalls or some unexpected features, and it would be great to know about them before starting working on B&R support in the checker.

Otherwise, if they just use the same language as in matiec, and they just use separate files to define different components, it is possible to extend iec-checker to support this.

[bubkuh]

Hi @jubnzv, thanks for the feedback.

The language itself should basically be the same, as I have already successfully used the iec-checker by reorganizing the code into the expected structure before execution.

Here is an excerpt from the Automation Studio 4.12.2.65 documentation about the detailled differences:

IEC compliance list

Automation Studio meets the requirements of IEC 61131-3, Ed. 2 in the points listed below in the table that are marked with "Yes".

Table no.	Description	Automation Studio	Note
1	Character set features
1-2	lower case	Yes
1-3a	Number sign (#)	Yes	In time constants
1-3b	Pound sign	No	Except for comments and strings
1-4a	Dollar sign ($)	Yes
1-4b	Currency sign	No	Except for comments and strings
1-5a	Vertical bar (|)	No	Except for comments and strings
1-5b	Exclamation mark (!)	No	Except for comments and strings
2	Identifier features
2-1	Upper case and numbers	Yes	Mixed cases generates significant identifiers (aBcD not equal to ABcD)
2-2	Upper and lower case numbers and embedded underlines	Yes
2-3	Upper and lower case numbers and embedded or leading underlines55	Yes
3	Comment features
3-1	Comments	Yes
3a	Pragma feature
3a-1	Pragmas	No
4	Numeric literals
4-1	Integer literals	Yes
4-2	Real literals	Yes
4-3	Real literals with exponent	Yes
4-4	Base 2 literals	Yes	2#1111_0000
4-5	Base 8 literals	Yes	8#377
4-6	Base 16 literals	Yes	16#00FF
4-7	Boolean 1 and 0	Yes
4-8	Boolean TRUE and FALSE	Yes
4-9	Typed literals	Yes	DINT#10
5	Character string literals
5-1	Single byte character string
	''	Yes
	'A'	Yes
	' '	Yes
	'$''	Yes
	'"'	Yes
	'$R$L'	Yes
	'$0A'	Yes
	'$$1.00'	Yes
	'$C4$CB'	Yes
5-2	Double byte character strings	No
6	Two-character combinations in character strings
6-2	$$	Yes
6-3	$'    (Single quote)	Yes
6-4	$L or $l	Yes
6-5	$N or $n	Yes	Line feed (dec. 10)
6-6	$P or $p	Yes
6-7	$R or $r	Yes
6-8	$T or $t	Yes
6-9	$"   (Double quote)	Yes
7	Duration literals
7-1a		Yes
7-1b		Yes
7-2a		Yes
7-2b		Yes
8	Date and time-of-day literals
8-1	DATE#	Yes
8-2	D#	Yes
8-3	TIME_OF_DAY#	Yes
8-4	TOD#	Yes
8-5	DATE_AND_TIME#	Yes
8-6	DT#	Yes
10	Elementary data types
10-1	BOOL	Yes
10-2	SINT	Yes
10-3	INT	Yes
10-4	DINT	Yes
10-5	LINT	No
10-6	USINT	Yes
10-7	UINT	Yes
10-8	UDINT	Yes
10-9	ULINT	No
10-10	REAL	Yes
10-11	LREAL	Yes
10-12	TIME	Yes
10-13	DATE	Yes
10-14	TIME_OF_DAY or TOD	Yes
10-15	DATE_AND_TIME or DT	Yes
10-16	STRING	Yes
10-17	BYTE	Yes
10-18	WORD	Yes
10-19	DWORD	Yes
10-20	LWORD	No
10-21	WSTRING	Yes
12	Data type declaration features
12-1	Derivation from elementary types	Yes
12-2	Enumerated data types	Yes
12-3	Subrange data types	Yes
12-4	Array data types	Yes
12-5	Structured data types	Yes
14	Data type initial value declaration features	Yes
15	Location and size prefixes for directly represented variables
15-1	Prefix I	Yes
15-2	Prefix Q	Yes
15-3	Prefix M	Yes
15-4	Width X	Yes
15-5	No prefix	No
15-6	Width B	Yes
15-7	Width W	Yes
15-8	Width D	Yes
15-9	Width L	No
15-10	Use of an asterisk *	No
16	Variable declaration keywords
16-1	VAR	Yes
16-2	VAR_INPUT	Yes
16-3	VAR_OUTPUT	Yes
16-4	VAR_IN_OUT	Yes
16-5	VAR_EXTERNAL	No
16-6	VAR_GLOBAL	Yes
16-7	VAR_ACCESS	No
16-8	VAR_TEMP	No
16-9	VAR_CONFIG	Yes
16-10	RETAIN	Yes
16-11	NEINN_RETAIN	No
16-12	CONSTANT	Yes
16-13	AT	Yes
17	Variable type assignment feature
17-1		No
17-2		No
17-3		Yes
17-4		No
17-5		Yes
17-6		Yes
17-7		Yes
17-8		Yes
18	Variable initial value assignment
18-1		No
18-2		No
18-3		No
18-4		No
18-5		Yes
18-6		Yes
18-7		Yes
18-8		Yes
18-9		Yes
18-10		Yes
19	Graphical negation of boolean signal
19-1		Yes	In Function Block Diagram
19-2		No
19a	Textual invocation of functions for formal and non-formal argument list
19a-1		Yes	For function blocks
19a-2		Yes
20	Use of EN input and ENO output
20-1		Yes	In Ladder Diagram with Automation Studio V3.0.71 No error evaluation after table E.1, EN is passed on to ENO. Division by 0 can be handled in the exception task.
20-2		Yes	In Ladder Diagram with Automation Studio V3.0.71 or higher
20-3		No
20-4		No
20a	Function features
20a-1		Yes
20a-2		Yes
20a-3		Yes
21	Typed and overloaded functions
21-1		Yes
21-2		Yes
22	Type conversion function features
22-1		Yes	The CONVERT library contains the declarations for all supported conversion functions in IEC 1131-3. With Automation Runtime >= V3.08 (SG4), V2.32 (SGC), V2.52 (SG3) the AsIecCon library is available. This contains the conversion routines for the base data types available in Automation Studio 3.0.90 (BYTE, WORD, DWORD, TOD, WSTRING).
22-2		Yes
22-3		No
22-4		No
23	Standard functions of one numeric variable		The OPERATOR library contains the declarations of all the functions defined in table 23.
23-1	ABS	Yes
23-2	SQRT	Yes
23-3	LN	Yes
23-4	LOG	Yes
23-5	EXP	Yes
23-6	SIN	Yes
23-7	COS	Yes
23-8	TAN	Yes
23-9	ASIN	Yes
23-10	ACOS	Yes
23-11	ATAN	Yes
24	Standard arithmetic  functions		The OPERATOR library contains the declarations of all the functions defined in table 24.
24-12	ADD	Yes	Expandable function
24-13	MUL	Yes	Expandable function
24-14	SUB	Yes
24-15	DIV	Yes
24-16	MOD	Yes
24-17	EXPT	Yes
24-18	MOVE	Yes	Expandable function
25	Standard bit shift functions		The OPERATOR library contains the declarations of all the functions defined in table 25.
25-1	SHL
25-2	SHR
25-3	ROR
25-4	ROL
26	Standard bitwise boolean functions		The OPERATOR library contains the declarations of all the functions defined in table 26.
26-5	AND	Yes	Expandable function
26-6	OR	Yes	Expandable function
26-7	XOR	Yes	Expandable function
26-8	NOT	Yes
27	Standard selection functions		The OPERATOR library contains the declarations of all the functions defined in table 27.
27-1	SEL	Yes
27-2a	MAX	Yes	Expandable function
27-2b	MIN	Yes	Expandable function
27-3	LIMIT	Yes
27-4	MUX	Yes	Expandable function
28	Standard comparison functions		The OPERATOR library contains the declarations of all the functions defined in table 28.
28-5	GT	Yes
28-6	GE	Yes
28-7	EQ	Yes
28-8	LE	Yes
28-9	LT	Yes
28-10	NE	Yes
29	Standard character string  functions		The STANDARD library contains the declarations of all the functions defined in table 29.
29-1	LEN	Yes
29-2	LEFT	Yes
29-3	RIGHT	Yes
29-4	MID	Yes
29-5	CONCAT	Yes
29-6	INSERT	Yes
29-7	DELETE	Yes
29-8	REPLACE	Yes
29-9	FIND	Yes
30	Functions of time data types	No	The AsTime library implements some of the functions defined in Table 30.
31	Functions of enumerated data types	No	Enumeration data types not supported
33	Function block declaration and usage features
33-1a		No
33-1b		No
33-2a		No
33-2b		No
33-3a		No
33-3b		No
33-4a		Yes
33-4b		Yes
33-5a		Yes
33-5b		Yes
33-6a		Yes
33-6b		Yes
33-7a		No
33-7b		No
33-8a		No	Can be replicated with R_TRIG
33-8b		No	Can be replicated with F_TRIG
33-9a		No	Can be replicated with R_TRIG
33-9b		No	Can be replicated with F_TRIG
33-10a		No
33-10b		No
33-11		No
34	Standard bistable function blocks		The STANDARD library contains the declarations of all the functions defined in table 34.
34-1		Yes
34-2		Yes
35	Standard edge detection function blocks		The STANDARD library contains the declarations of all the functions defined in table 35.
35-1		Yes
35-2		Yes
35-1a		Yes
35- 1b-1e		No
35-2a		Yes
35- 2b-2e		No
35-3a		Yes
35- 3b-3d		No
36	Standard timer function blocks		The STANDARD library contains the declarations of all the functions defined in table 35.
36-1		Yes
36-2a		Yes
36-3a		Yes
39	Program declaration features
33-1a		No
39-1b		No
39-2a		No
39-2b		No
39-3a		No
39-3b		No
39-4a		Yes
39-4b		Yes
39-5a		Yes
39-5b		Yes
39-6a		Yes
39-6b		Yes
39-7a		No
39-7b		No
39-8a		No	Can be replicated with R_TRIG
39-8b		No	Can be replicated with F_TRIG
39-9a		No	Can be replicated with R_TRIG
39-9b		No	Can be replicated with F_TRIG
39-10		No
39-11		No
39-12		No
39-13		Yes
39-14		No
39-15		No
39-16		No
39-17		Yes
39-18		Yes	Arrays only initialized with 0
39-19		No
39-20		No
39-21		No
39-22a		No
39-22b		No
39-23		No
39-24		No
40	Sequential function chart Step features
40-1		Yes
40-2		Yes
40-3a		Yes	Only for action blocks! Using the step flag (Step.x := TRUE) doesn't generate an error message.
40-3b		Yes	Only for action blocks! Using the step flag (Step.x := TRUE) doesn't generate an error message.
40-4		Yes	Only for action blocks!
41	Sequential function chart Transition and transition conditions		Using direct variables not possible
41-1		Yes
41-2		Yes
41-3		Yes
41-4		Yes	By jumping to the respective step
41-4a		Yes
41-4b		Yes
41-5		Yes
41-6		Yes
41-7		Yes
41-7a		Yes
41-7b		Yes
41-7c		Yes
41-7d		Yes
42	Declaration of actions
42-1		Yes
42-2l		Yes
42-2s		Yes
42-2f		Yes
42-3s		Yes
42-3i		Yes
43	Step/action association
43-1		Yes
43-2		Yes
43-3		No
43-4		Yes
44	Action block features
44-1		Yes
44-2		Yes
44-3		No
44-4		Yes
44-5		Yes
44-6		Yes
44-7		Yes
44-8		Yes	With Automation Studio V3.0.71 or higher
44-9		No
45	Action qualifiers
45-1		Yes
45-2		Yes
45-3		Yes
45-4		Yes
45-5		Yes
45-6		Yes
45-7		Yes
45-8		Yes
45-9		Yes
45-10		Yes
45-11		Yes
45-12		Yes
45a	Action control features
45a-1		Yes	In Sequential Function Chart, and with Automation Studio V3.0.71 and higher also in Ladder Diagram
45a-2		No
46	Sequence evolution
46-1		Yes
46-2a		Yes
46-2b		No
46-2c		No
46-3		Yes
46-4		Yes
46-5		Yes
46-6		Yes	By jumping to the respective step
46-7		No
48	SFC minimal compliance requirements	Yes
49	Configuration and resource declaration features
49-1		No
49-2		No
49-3		No
49-4		No
49-5a		Yes
49-5b		No
49-6a		No
49-6b		No
49-6c		Yes
49-7		No
49-8		No
49-9		No
49-10		No
49-11		Yes
49-12		No
49-13		No
50	Task features
50-1a		Yes
50-1b		No
50-2a		No
50-2b		No
50-3a		Yes	In XML syntax
50-3b		No
50-4a		No
50-4b		No
50-5a		No
50-5b		No
51	Parenthesized expression features for IL language
51-1		No
51-2		Yes
52	Instruction list operators
52-1	LD	Yes
52-2	ST	Yes
52-3	S R	Yes
52-4	AND	Yes
52-5	&	Yes
52-6	OR	Yes
52-7	XOR	Yes
52-7a	NOT	Yes
52-8	ADD	Yes
52-9	SUB	Yes
52-10	MUL	Yes
52-11	DIV	Yes
52-11a	MOD	Yes
52-12	GT	Yes
52-13	GE	Yes
52-14	EQ	Yes
52-15	NE	Yes
52-16	LE	Yes
52-17	LT	Yes
52-18	JMP	Yes
52-19	CAL	Yes
52-20	RET	Yes
52-21	)	Yes
53	Function block invocation and Function invocation features for IL language
53-1a		No
53-1b		Yes
53-2		Yes
53-3		No
53-4		No
53-5		Yes
54	Standard function block input operators
54-4		No
54-5		No
54-6		No
54-7		No
54-8		No
54-9		No
54-10		No
54-11		No
54-12		No
54-13		No
55	Operators of the ST language
55-1		Yes
55-2		Yes
55-3		Yes
55-4		Yes
55-5		Yes
55-6		Yes
55-7		Yes
55-8		Yes
55-9		Yes
55-10		Yes
55-11		Yes
55-12		Yes
55-13		Yes
55-14		Yes
55-15		Yes
55-16		Yes
55-17		Yes
56	ST language statements
56-1		Yes
56-2		Yes
56-3		Yes
56-4		Yes
56-5		Yes
56-6		Yes
56-7		Yes
56-8		Yes
56-9		Yes
56-10		Yes
57	Representing of lines and blocks
57-1		No
57-2		Yes
57-3		No
57-4		Yes
57-5		No
57-6		Yes
57-7		No
57-8		Yes
57-9		No
57-10		Yes
57-11		No
57-12		Yes
57-13		No
57-14		Yes
58	Graphic execution control elements
58-1		Yes
58-2		Yes
58-3		Yes
58-4		Yes
58-5		Yes
58-6		Yes
58-7		Yes
58-8		Yes
59	Power rails
59-1		Yes
59-2		Yes
60	Link elements
60-1		Yes
60-2		Yes
61	Contacts
61-1		Yes
61-2		No
61-3		Yes
61-4		No
61-5		Yes
61-6		No
61-7		Yes
61-8		No
62	Coils
62-1		Yes
62-2		Yes
62-3		Yes
62-4		Yes
62-8		Yes
62-9		Yes

D.1 - Implementation dependent parameters

Clause	Parameter	Automation Studio
2.1.2	Maximum length of identifiers	32
2.1.5	Maximum comment length	No limit
2.2.3.1	Range of TIME variables	T#-24d_20h_31m_23s_648ms ...T#24d_20h_31m_23s_647ms
	Range of TIME_OF_DAY variables	TOD#00:00:00 ... TOD#23:59:59.999
	Range of DATE_AND_TIME variables	DT#1970-01-01-00:00:00 ... DT#2106-02-07-06:28:15
2.3.3.1	Maximum numbers of enumerated values	No limit
	Maximum numbers of array subscript	1
	Maximum array size	4095 for array as structure element 32 KB
	Maximum numbers of structure elements	No limit
	Maximum structure size	32 KB
	Maximum range of subscript values	No limit
	Maximum number of levels of nested structures	16
2.3.3.2	Default maximum length of STRING and WSTRING	80
	Maximum allowed length of STRING and WSTRING	Limited by the maximum amount of memory that can be configured for the target.
2.4.1.1	Maximum number of hierarchical levels	No limit
	Logical or physical mapping	Physical mapping
2.4.2	Initialization of system inputs	System inputs are copied to the assigned variable areas before the first task is started. An exception is thrown for defective or missing I/O modules on SG3 targets. On SG4 targets, you can set whether an exception is thrown or the default value 0 should be used.
2.4.3	Maximum number of variables per declaration	Variables up to max. 64 KB can be created. The number is not important and depends on the data types of the variables. For example, approx. 64,000 variables of type USINT, 32,000 variables of type INT, 16,000 variables of type DINT, etc.
2.5	Information necessary to determine execution times of POUs	Cycle time monitoring of the respective task class by the operating system
2.5.1.2	Values of outputs when EN is FALSE	Result of the last execution of the block remains
2.5.1.3	Maximum number of function specifications	SG4: no limit SG3: configurable (0..65535)
2.5.1.5	Maximum number of inputs of extensible functions	Extensible functions are only possible in FBD/CFC. Automation Studio 2.x: 220 Automation Studio 3.0 and up: 1024
2.5.2	Maximum number of function block specifications and instantiations	SG4: no limit SG3: configurable (0..65535)
2.5.2.1a	Function block input variable assignment when EN is FALSE	Not supported
2.5.2.3.3	Pvmin, Pvmax of counters	0...65535 (CTD, CTU) -32768...32767 (CTUD)
2.5.2.3.4	Effect of a change in the value of a PT input during a timing operation	PT applied and checked immediately
2.5.3	Program size limitations	64KB
2.6.2	Precision of step elapsed time.	For the task's configured cycle time
	Maximum number of steps per SFC.	No limit
2.6.3	Maximum number of transitions per SFC and per step	No limit
2.6.4.2	Maximum number of action blocks per step	10
2.6.4.5	Access to the functional equivalent of the Q or A outputs	No
2.6.5	Transition clearing time	The step switch takes place at the end of the task cycle if necessary.
2.7.1	Contents of RESOURCE libraries	Not implemented
2.7.1	Effect of using READ_WRITE access to the function block outputs	Outputs are overwritten in each cycle. Otherwise, it depends on the implementation in the respective block.
2.7.2	Maximum number of tasks per resource	SG4: Up to 8 task classes can be configured! SG3: Can be set depending on the target!
	Task interval resolution	Configurable
3.3.1	Maximum length of expressions	No limit
3.3.2	Maximum length of statements	No limit
3.3.2.3	Maximum number of CASE selections	No limit
3.3.2.4	Value of control variable after completion of the FOR loop	One step below the limit
4.1.1	Restriction on network topology	Full graphics. Max. number of columns in Ladder Diagram: 50 Max. number of columns in FBD and CFC: 64 Max. number of lines in CFC: 65535 Max. number of networks in FBD: 65535 Max. number of lines per network in FBD: 65535
4.1.3	Evaluation order of feedback loops	Explicit loops according to 4.1.3. Fig. 23a are not permitted. Implicit return according to 4.1.3. Fig. 23a and b are allowed. Evaluation takes place for each network from top to bottom and right to left.

[jubnzv]

@bubkuh Got it, thank you for the information.

I think, we don't need to do anything related to the language support in the checker, since it seems to be the same. All the limitations and differences specific to Automation Studio should be checked during the compilation by its toolchain.

To make it easier to use iec-checker for B&R programs, I propose to add support for multiple input files. The idea is that the checker will treat all input files as if they were a single file, merge their internal representation (IR) and then run analyses over it.

The pitfall of this implementation is that name collisions for components in these files are not allowed. For example, it will not possible to define STRUCT with the same name in two input files. I don't think this will cause any problems yet, because I personally don't know of any implementation of the IEC61131-3 language that treats definitions from different files as if they were placed in different namespaces.

[jubnzv]

Hi @bubkuh,

I added the -merge option to the checker, that should solve this problem. Basically, it first merges all the input files into one, and then runs analysis on it.

I kept the default behavior of handling multiple input files. If the -merge option is not specified, they will be processed individually. I remember that we needed this when adding support for another IDE before: https://github.com/jubnzv/iec-checker/issues/6.

Could you please try the -merge option?

Please, re-open this issue if you have any questions or suggestions. It was closed automatically when merging the corresponding PR.