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BaSyx / Documentation / API / ControlComponentProfiles

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Revision as of 09:14, 20 March 2020 by (Talk | contribs) (Profiles: Added interface description for profiles.)

This information is work in progress as part of the BaSys 4.2 project. This section is preliminary and subject to change during the project.

Overview | Interface | Implementation


An example control component in OPC UA realizing different facets.

A profile is a composition of facets from different facet categories. For example a control component profile can be defined by the following facets.

  • EM = 2 (MANUAL)
  • ES = 4 (PACKML)
  • OM = 2 (MULTI)

The address space of a control component in OPC UA conforming to this profile is shown in the figure.

Facets ordered in different facet categories may describe a huge variety of control component realizations. Consequently, profiles are needed to reduce the amount of facet combinations to a usefull subset. The profiles are not defined right now, as this is part of the ongoing BaSys 4.2 project. Every profile will refer to at least one facet from every facet category and will therefore be considered as full featured profile. At first some important profiles may be defined in the future:

  • BaSys4.0 - Control components as used in the BaSys 4.0 project
  • BaSys4.2 - Control components conform to the BaSys 4.2 project
  • MTP - Control components that are NAMUR MTP conform
  • PACKML - Control components that are conform to PackML

In order to describe the variant and its features, respectively the profile, of a control component an interface specification is given here. It may be used in type or instance descriptions, e.g. in AAS submodels, or even in the control component itself. A self description of control components is an important feature to enable plug and produce scenarios.

Parent Name Type Rule Property Datatype Property Values
PROFILE Property Group Optional
PROFILE SI Property Optional String SI Facets
PROFILE OC Property Optional String OC Facets
PROFILE EM Property Optional String EM Facets
PROFILE ES Property Optional String ES Facets
PROFILE OM Property Optional String OM Facets

Facet Categories

BaSys control components may be described by the following facet categorys:

SI - Service Interface Facet Category
Describes how the offered services are structured and how states are represented.
This facet category is special, because it is orthogonal to the other facet categories. Hence, a control component interface looks a bit different, if different facets from the other facet categories are realised.
OC - Occupation Facet Category
Describes whether a occuption is necessary.
Variants may describe whether a occupation with priority or local is possible.
EM - Execution Modes Facet Category
Describes whether different execution modes are possible.
Variants may describe which modes are possible and how they are called.
ES - Execution States Facet Category
References the used execution states and their transitions.
May describe variants or subsets of a full execution state state machines.
OM - Operation Modes Facet Category
Describes whether multiple operation modes are available and need to be selcted.
Variants may describe whether there are specific operation modes, like fallback or startup and shutdown modes.

Facet Category Values

All facets have a name and are identfied with an positiv integer or zero. In order to combine facet category values and to use them as statements some common values are equal for all profiles, which is presented in the following table. If a facet category value is higher than one, ANY facet is defined for a facet category, which is opositional to the NONE value.

Facet categories may either describe a group of features that are combinable or a variant point that lists alternative realizations. If different facets in one facet group may be combined they are defined by bitmasks. Hence their values are multiples of two and combinations may be represented by bit order operations and integer values. Otherwise enumerations with an increment of one are used for alternative facet categories.

Bit Value Name Description
1 0 UNKNOWN No statement about profile or not determined
1 1 NONE Facet category is not realised, used, compliant or implemented
2..n >1 ANY One ore more facet category values, but not specified which ones
2 2 ... First specific facet of the facet category.
n 2^n ... Nth specific facet of the facet category.


SI Facets

The control component service interface E1 may be realised in various ways. Basys classifies different realisations via facets from the SI facet category. The service interface category (SI) describes how a control component can be affected by the means of orchestration and how the resulting state changes may be observed. Therefore each facet defines how the activation interaction likewise the writing of variables or invocation of operations is handled. Moreover, a component has aggregated state values for its state machines, which may be represented by one or more variables at different adresses. State change events may be raised if state variable values change. Consequently, the SI facets also define how to find the addresses or endpoints of its activation and reaction represenations.

The following table presents an overview and small comparision of possible SI facets. The major facet for the service interface used in basys is OPERATIONS.

Bit SI value Name Activation mechanism Aggregated state represenation Utiliziation recommendation
1 0 - 1 UNKNOWN, NONE Not defined Not defined See category values
2 2 CMD A string variable called CMD (command input) with a specific syntax is used to activate service operations A flat list of variables of all aggregated component states under a containing element (folder) Process control applications with IEC 61131
3 4 OPERATIONS A flat list of operations of all offered services under a containing element (folder) A flat list of variables of all aggregated component states under a containing element (folder) Advanced components or as additional interface
4 8 SERVICES Operations are grouped under service elements State variables are grouped under service elements Advanced and modular components
5 16 VARIABLES Multiple (spread) variables are used to activate service operations Multiple (spread) variables are used to represent the component states Very generic but needs mapping description. Not standardized browseable. May be mapped to NAMUR MTP

Note on NAMUR Module Type Package (MTP): in the future, basys will map the description for the orchestration of modules that are described via a NAMUR MTP to facets or even to a profile. Therefore an existing facets like VARIABLES may be used or a new facet may be necessary.

OC Facets

The occupation facet category describes, whether a control component can be occupied. This is important for an orchestrator, as it has to be checked, whether the component is free and it has to be occupied before operation. Further more, the occupation facets determine, whether it is possible to occupy the component with a higher priority, for example by an operator or maintenance person. An OC value of two or higher (ANY) requries the component to have an OCCUPIER variable to determine who occupies the component. Moreover, the OCCST variable is needed to differentiate occupation states.

Bit Value Name Description Possible OCCST values Possible ORDERs
- 0 UNKNOWN See category values Undefined Undefined
1 1 NONE No occupation necessary - -
2 2 OCCUPIED Normal occupation possible FREE, OCCUPIED FREE, OCCUPY
3 4 PRIO Priority occupation possible FREE, PRIO FREE, PRIO
4 8 LOCAL Local overwrite FREE, LOCAL

EM Facets

The execution mode facet category describes which execution modes are available. A component is assumed to be in AUTO like mode at all time, if the ES value is NONE. An ES value of two or higher (ANY) requires a EXMODE variable to determine the current mode.

Bit Value Name Description Possible EXMODE values = Possible ORDERs
- 0 UNKNOWN See category values Undefined
1 1 NONE Always in AUTO -
2 2 MANUAL Additional manual mode available AUTO, MANUAL
3 4 SEMIAUTO Additional semiautomatic mode available AUTO, SEMIAUTO
4 8 SIMULATE Additional simulation mode available AUTO, SIMULATE

ES Facets

In general different execution state machines or subsets are used in different domains or companies. BaSys recommends the use of the PackML [1] state machine, as it is possible to map at least state and order names of other state machines to it. At the moment only the facets 0 to 4 are supported in basys and are therefore used in the full featured profiles. [2]

The EXST variable has to be present, if an ES value of two (ANY) or higher is given. A control component with ES value one (NONE) is assumed to be in the EXECUTE state at all time and hence it can not be halted, suspended, stopped or aborted.

Value Name Description Reference
0 UNKNOWN See category values -
1 NONE Always in EXECUTE state Minimal state model[2]
2 BASYS Subset of PackML (Start, Stop, Reset, Abort) Minimal PackML state machine[2]
3 PACKML PackML state machine ISA TR88.00.02-2008[1]
4 ISA88 ISA88 procedural elements state machine ANSI/ISA-88.00.01-2010[3]
5 MTP MTP state machine MTP Part 4[4]
6 OPCUA OPC UA program state machine OPC UA Part 10[5]
7 NE160 NE160 procedure state machine NAMUR NE160[6]

OM Facets

The operation mode facets define whether different operation modes are selectable. A control component with an OM value of two or higher has to represent the current operation mode via OPMODE state variable. The OM value NONE yields to a control component, that has no operation modes to select and is therefore assumed to be in basic state (BSTATE) at all time.

Value Name Description
0 UNKNOWN See category values
1 NONE No operation mode selection possible.
2 MULTI One or multiple, application specific modes, that need to be selected.
3 PARALLEL Parallel executable operation modes with own execution states. See components with concurrent behavior.
4 CONTI Conti process operation mode with startup and shutdown: CONTI, STARTUP, SHUTDOWN


  1. 1.0 1.1 ISA-TR88.00.02-2008 Machine and Unit States: An Implementation Example of ISA-88.
  2. 2.0 2.1 2.2 Wagner, C., Grothoff, J., Epple, U., Grüner, S., Wenger, M., & Zoitl, A. (2018). Ein Beitrag zu einem einheitlichen Engineering für Laufzeitumgebungen, 19. Leitkongress der Mess- und Automatisierungs-technik, Baden-Baden.
  3. ISA-S88 Part 1 – Batch Control Models and Terminology (IEC 61512-1)
  4. VDI/VDE/NAMUR 2658 Part 4 - Modelling of module services
  5. IEC 62541 Part 10 – Programs
  6. NAMUR NE160 - Ein Referenzmodell für allgemeine Prozedurbeschreibungen, NAMUR, 2016.
BaSyx project links: Project BaSyx main wiki page | What is BaSyx? | BaSyx Developer Documentation

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