Vorto Language for Digital Twins

Version 1.0

Introduction

This document specifies the Vorto Language (vortolang 1.0), a language for describing models and interfaces for IoT Digital Twins. Digital twins are models of entities in the physical world such as a (multi) sensor device, smart power plant, and other entities that participate in IoT solutions. Modeling enables IoT solutions and IoT platforms to provision, use, and configure IoT devices and logical entities from multiple sources in a single solution. Using the vortolang and describing the entities's capabilities, IoT platforms and IoT solutions can leverage the semantics of these IoT entities.

Digital Twin Vorto Language

Digital twins are described using the vortolang, which is domain-specific language (DSL). This DSL underlies a very simple grammar, making it very easy to describe digital twin models. In order to be used in IoT Platforms and solutions, the vortolang can easily be converted into well adopted languages, such as JSON-LD, where additional context-specific attributes can be added. Many (free) libraries are available to process these language files. At definition time, developers can use the vortolang without any knowledge about JSON-LD or others, and fully focus on describing the device capabilities in a very expressive way.

The vortolang is made up of a set of metamodel classes (described later in more detail) that define the capabilities of digital twins. There are two top-level classes, Information Model and Function Block, that describe a digital twin and the capabilities of digital twins, respectively. There are three metamodel classes that describe capabilities: Properties, Events, and Operations. When writing a digital twin definition, it's necessary to specify the version of the vortolang being used (currently 1.0)

Information Models and Function Blocks

There are two top-level metamodel classes: Information Model and Function Block. Information Models describe a complete digital twin, such as a physical device. Often, Information Models are associated with a specific device product, such as a "Bosch Dinion IP Starlight 8000MP" security camera, while Function Blocks describe the related capabilities of an digital twin (its status- and configuration properties, events, and operations). Function Blocks can be reused across different Information Models. Information Models are often made up of multiple Function Blocks (interfaces).

Information Model

An Information Model describes a complete digital twin, such as a physical device and defines the set of interfaces as Function Blocks, implemented by the digital twin.

Information Model properties

Keyword	Required	Data type	Description
vortolang	required	string	Identifies which vortolang version used to define the Information Model. Currently '1.0'
namespace	required	string	The name must match the regular expression: `name('.' name )*`
version	required	string	The name must match the regular expression: `/^\d+\.\d+\.\d+(-\\w+)*$/`
displayname	optional	string	a name of the information model for human display
description	optional	string	A description for human display.
category	optional	string	Custom tag to categorize the model, e.g. sensor, smarthome/kitchen etc. The name must match the regular expression: `name('/' name )*`
using	required	A set of `Model Reference`s	Defines the imported models that are referenced by this Information Model under 'functionblocks'
infomodel	required	string	The name must match the regular expression: `^[A-Z][a-zA-Z0-9]*$`
functionblocks	required	A set of `Model Property` of type `Function Block`	A set of Function Block properties.

BNF (Backus normal form)

InformationModel:
    'vortolang' 1.0

    'namespace' qualifiedName
    'version' version
    ('displayname' string)?
    ('description' string)?
    ('category' ID('/' ID)*)?

    (modelReference)*

    'infomodel' ID '{'
    'functionblocks' '{'
        (functionblockProperty)*
    '}'
;

functionblockProperty: 
	('mandatory' | 'optional')? ('multiple')? ID 'as' [FunctionBlock::ID | qualifiedName] (description)?

qualifiedName: ID ('.' ID)*;

version : int('.' int)*('-'ID)?;

ID:
    '^'?('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*
;

description: STRING

modelReference: 
	'using' qualifiedName ';' version;

Example:

vortolang 1.0

namespace com.mycompany
version 1.0.0
description "Information model for FabLab.eu's IoT Octopus"
category multisensor

using com.ipso.smartobjects.Accelerometer ; 1.1.0
using com.ipso.smartobjects.Barometer ; 1.1.0

infomodel IoTOctopus {

	functionblocks {
		mandatory accelerometer as Accelerometer "some description"
		optional barometer as Barometer
	}
}

Function Block

A Function Block describes related capabilities that are implemented by a digital twin. Function Blocks are reusable and can be reused across different Information Models.

Function Block properties

Keyword	Required	Data type	Description
vortolang	required	string	Identifies which vortolang version used to define the Function Block. Currently '1.0'
namespace	required	string	The name must match the regular expression: `name('.' name )*`
version	required	string	The name must match the regular expression: `/^\d+\.\d+\.\d+(-\\w+)*$/`
displayname	optional	string	a name of the information model for human display
description	optional	string	A description for human display.
category	optional	string	Custom tag to categorize the model, e.g. sensor, smarthome/kitchen etc. The name must match the regular expression: `name('/' name )*`
using	required	A set of `Model Reference`s	Defines the imported models that are referenced by this Information Model under 'functionblocks'
functionblock	required	string	The name must match the regular expression: `^[A-Z][a-zA-Z0-9]*$`
extends	optional	ID of a `Function Block`	Extends another `Function Block` by specializing it with extended properties
configuration	optional	Configuration `Properties`	An object describing configuration `Properties`. Configuration properties are read-writable by default.
status	optional	Status `Properties`	An object describing status `Properties`. Status properties are read-only by default.
events	optional	a set of `Event`s	Describes data emitted by a device or other entity
operations	optional	a set of `Operation`s	Describes functions that can be performed on the device or entity.

BNF (Backus normal form)

FunctionBlock:
    'vortolang' 1.0

    'namespace' qualifiedName
    'version' version
    ('displayname' string)?
    ('description' string)?
    ('category' ID('/' ID)*)?

    (modelReference)*

   'functionblock' ID ('extends' [Functionblock::ID | qualifiedName])? '{'
		('configuration' '{' 
			(Property)*
		'}')?
		
		('status' '{' 
			(Property)*
		'}')?

		('events' '{' 
			(ID '{'
				(Property)*
			'}')*
		'}')?
		
		('operations' '{'
			(Operation)*
		'}')?	
		
	'}'	
;

qualifiedName: ID ('.' ID)*;
version : int('.' int)*('-'ID)?;
ID: '^'?('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*;
modelReference: 'using' qualifiedName ';' version;
description: STRING

Property: Please refer to chapter Model Property for details

Operation:
 ('extension')? ('mandatory' | 'optional')? ('breakable')? ID '(' (OperationType (',' OperationType)*)?')' ('returns' OperationType)? (description)?;

OperationType: DictonaryOperationType | OperationPrimitiveType | OperationObjectType;

DictonaryOperationType:
('multiple')? ID 'as' DictionaryType ('<' ConstraintRule '>')?  (description)?;

OperationPrimitiveType: ('multiple')? ID 'as' PrimitiveType ('<' ConstraintRule '>')?  (description)?;

OperationObjectType: ('multiple')? ID 'as' ObjectType (description)?;

Example:

vortolang 1.0

namespace com.mycompany
version 1.0.0

functionblock Accelerometer {

	configuration {
		mandatory enable as boolean
	}

	status {
		mandatory xValue as float "The measured value along the X axis."
		optional yValue as float "The measured value along the Y axis."
		optional zValue as float "The measured value along the Z axis."
	}
	
	operations {
		reset() returns boolean "resets the accelerometer"
	}
}

Properties

Properties describe both read-only and read-write state of a digital twin. Read-only properties are defined as status properties, whereas read-write properties as configuration properties. For example, a device serial number may be a status property and the temperature set point on a thermostat may be a configuration property.

Function Block property is defined as a Model Property

Status Property Example

functionblock Thermostat {
...
	status {
		mandatory serialNumber as string
	}
}

Configuration Property Example

functionblock Thermostat {
...

	configuration {
		optional temperature as float <MIN 0, MAX 35> "writable temperature with a range constraint"
		mandatory enable as boolean "enables the sensor to start sending data"
	}
}

Event

Events define data that is emitted by the device or entity. This kind of data would need to be transmitted to an IoT business solution in a reliable way.

An Event property is defined as a Model Property

Event Example

functionblock Geolocation {
...
	events {
		enterFence {
			entryPoint as Location3D
			timestamp as dateTime		
		}
		leaveFence {
			exitPoint as Location3D
			timestamp as dateTime	
		}
	}
}

Operation

An operation represents a function that can be performed on a Digital Twin. Operations may have request params as well as a return type

Keyword	Required	Description
breakable	Optional	Signals, that it could eventually cause an error when performing the operation on the device
operation name	required	Name of the operation
request params	optional	request params, separated by `,`
response type	optional	Specifies a response of the operation. Response type must comply to `Data Type`
description	optional	A description for human display

Example

op() "A simple operation without request and response types"

breakable op() "An operation that could cause an error when performed"

op() returns int "Operation that returns a primitive type"

op() returns multiple int "Operation that returns an array of a primitive type"

op(msg as string) "Operation with a single primitive param"

op(multiple msg as string "msg description") "array param with description"

op(msg as int <MIN 0, MAX 100>) "Param with constraint"

Data Types

Primitive Types

A full set of primitive data types are provided and can be specified directly as a type value of a model property.

Primitive Schema	Description
boolean	a boolean value
dateTime	A date and time in ISO 8601 format
double	An IEEE 8-byte floating point number
float	An IEEE 4-byte floating point number
int	A signed 4-byte integer
long	A signed 8-byte integer
string	A UTF8 string
base64Binary	Represents an arbitrary binary content
base64Binary	Represents an arbitrary binary content
short	A short 16-bit integer between -32768 and 32767
byte	A 8-bit integer between -128 and 127

Enum

An enum is an enumeration of values of the same type similar to an enum in Java.

Keyword	Required	Data type	Description
vortolang	required	string	Identifies which vortolang version used to define the Enumeration. Currently '1.0'
namespace	required	string	The name must match the regular expression: `name('.' name )*`
version	required	string	The name must match the regular expression: `/^\d+\.\d+\.\d+(-\\w+)*$/`
displayname	optional	string	a name of the enumeration model for human display
description	optional	string	A description for human display.
category	optional	string	Custom tag to categorize the model, e.g. sensor, smarthome/kitchen etc. The name must match the regular expression: `name('/' name )*`
literal	required	a set of literal values	Multiple literal values are separated by `,` It must match the regular expression: `('a'..'z'\|'A'..'Z'\|'_'\|'0'..'9')*`
literal description	optional	string	A description for human display.

BNF (Backus normal form)

Enumeration:
    'vortolang' 1.0

    'namespace' qualifiedName
    'version' version
    ('displayname' string)?
    ('description' string)?
    ('category' ID('/' ID)*)?

   'enum' ID '{'
		(enumLiteral) (',' enumLiteral)*
	'}'	
;

qualifiedName: ID ('.' ID)*;
version : int('.' int)*('-'ID)?;
ID: '^'?('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*;
description: STRING

 enumLiteral: ID (description)?

Example

vortolang 1.0

namespace com.mycompany
version 1.0.0

enum Unit {
	kg "Kilogram unit" , 
	g "gram unit"
}

Entity

Keyword	Required	Data type	Description
vortolang	required	string	Identifies which vortolang version used to define the Enumeration. Currently '1.0'
namespace	required	string	The name must match the regular expression: `name('.' name )*`
version	required	string	The name must match the regular expression: `/^\d+\.\d+\.\d+(-\\w+)*$/`
displayname	optional	string	a name of the enumeration model for human display
description	optional	string	A description for human display.
category	optional	string	Custom tag to categorize the model, e.g. sensor, smarthome/kitchen etc. The name must match the regular expression: `name('/' name )*`
using	required	A set of `Model Reference`s	Defines the imported models that are referenced by this Entity
extends	optional	Entity `name`	Expresses inheritance of entities
properties	optional	A set of `Model Property` elements	A set of `Model Property` elements

BNF (Backus normal form)

Entity:
    'vortolang' 1.0

    'namespace' qualifiedName
    'version' version
    ('displayname' string)?
    ('description' string)?
    ('category' ID('/' ID)*)?

    (modelReference)*

   'entity' ID ('extends' [Entity::ID | qualifiedName])? '{'
		(property)*			
	'}'	
;

qualifiedName: ID ('.' ID)*;
version : int('.' int)*('-'ID)?;
ID: '^'?('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*;
modelReference: 'using' qualifiedName ';' version;
description: STRING

Property: Please refer to chapter Model Property for details

Example

vortolang 1.0

namespace com.mycompany
version 1.0.0

entity Color {  
	mandatory red as int <MIN 0, MAX 255> "The red component of a color"  
    mandatory green as int <MIN 0, MAX 255> "The green component of a color"    
    mandatory blue as int <MIN 0, MAX 255> "The blue component of a color"  
}

Dictionary

A dictionary describes values in a map.

Example

mandatory lookupTable as dictionary[string, Color] "Lookup table conversion for color"

mandatory lookupRGBTable as dictionary[Color, RGB] "Lookup table conversion for color from description to RGB"

mandatory temperatureLabelConversion as dictionary[int, string] "map of temperature to description"

mandatory simpleMap as dictionary "example of a map with no key and value types"

Model Property

A model property can be used by events, function block properties or entities.

Keyword	Required	Description
extension	optional	Indicates that the property is extended from a supertype with additional meta data
mandatory or optional	optional	Whether the property is mandatory or optional. Default is optional.
multiple	optional	Indicates if the property is an array type
with	optional	additional meta - data about the property, such as measurementUnit or if the property is readable or writable

BNF (Backus normal form)

Property:
		('extension')? ('mandatory] | 'optional')? ('multiple')? ID 'as' PropertyType
		('with' '{' PropertyAttribute (',' PropertyAttribute)* '}')?
		('<' ConstraintRule '>')?
		(description=STRING)?
	;

	PropertyType: ObjectType | PrimitiveType | DictionaryType;

	ObjectType: [Type::ID | qualifiedName];
	
	PrimitiveType: 
		'string' | 'int' | 'float' | 'boolean' | 'dateTime' | 'double' | 'long' | 'short' |'base64Binary' | 'byte';
	
	DictionaryType: 'dictionary' ('['PropertyType ',' PropertyType ']')?
	
	PropertyAttribute: BooleanPropertyAttribute | EnumLiteralPropertyAttribute;

	BooleanPropertyAttribute: ('readable' | 'writable') ':' ('true' | 'false');
	
	EnumLiteralPropertyAttribute: 'measurementUnit' ':' [Enum::ID | QualifiedName];

	Constraint: ('MIN' | 'MAX' | 'STRLEN' | 'REGEX' | 'MIMETYPE' | 'SCALING' | 'DEFAULT' | 'NULLABLE') IntervalType;

	IntervalType: INT | SIGNEDINT | FLOAT | DATETIME | STRING | BOOLEAN;

Example

Consider the following Enum which defines some Temperature Units

vortolang 1.0
namespace org.example
version 1.0.0
displayname "TemperatureUnits"
description "Datatype for TemperatureUnits"

enum TemperatureUnits {
    Kelvin "Degree Kelvin" , 
	Celsius "Degree Celsius",
	Fahrenheit "Degree Fahrenheit"
}

Then we can reference the measurement unit in a property as follows:

vortolang 1.0
namespace org.example
version 1.0.0
displayname "Test FB"
description "Functionblock for Example"

using org.example.TemperatureUnits;1.0.0

functionblock TestMu {
    status {
        temperature as float  with {
            measurementUnit: org.example.TemperatureUnits.Kelvin 
         }
    }
}

Note, in the example above we also say that the propery is readable.

Function Block Mapping

A Function Block Mapping describes a mapping of a Function Block and its properties for a specific platform.

BNF (Backus Normal Form)

    'vortolang' 1.0

    'namespace' qualifiedName
    'version' version
    ('displayname' string)?
    ('description' string)?
    ('category' ID('/' ID)*)?

    (modelReference)*
    
    'functionblockmapping' ID '{'
        'targetplatform' ID
        
        (MappingInstruction)*
        
    '}'
    ;
    
    ID: '^'?('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*;
    version : int('.' int)*('-'ID)?;
    qualifiedName: ID ('.' ID)*;
    modelReference: 'using' qualifiedName ';' version;
    MappingInstruction: 'from' ID to ID 'with '{' MappingProperty (',' MappingProperty)* '}'
    MappingProperty: ID ':' '"'string'"'

Further links

Describing a device with Vorto in 5 minutes
Describing a TI SensorTag

Files

vortolang-1.0.md

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Vorto Language for Digital Twins

Contents

Introduction

Digital Twin Vorto Language

Information Models and Function Blocks

Information Model

Information Model properties

BNF (Backus normal form)

Example:

Function Block

Function Block properties

BNF (Backus normal form)

Example:

Properties

Status Property Example

Configuration Property Example

Event

Event Example

Operation

Example

Data Types

Primitive Types

Enum

BNF (Backus normal form)

Example

Entity

BNF (Backus normal form)

Example

Dictionary

Example

Model Property

BNF (Backus normal form)

Example

Function Block Mapping

BNF (Backus Normal Form)

Further links