Table of Contents

UnitStateMachine

Namespace
ZApplication
Implements
FUNCTION_BLOCK UnitStateMachine IMPLEMENTS ZApplication.IUnitStateMachine, ZCore.IUnmanagedObject, ZCore.IObject, ZCore.IError

This is function block which implements the standard finite-state-machine of the Zeugwerk Template We have designed this standardized statemachine with predefined states which are defined in this UnitStateMachineState enumeration. There are also userdefined states possible by calling SetUserdefinedStateSequence and actions by calling SetUserdefinedActionSequence.

For more information on how to use the Zeugwerk Template Statemachine please read the doc here

Constructor

FB_init 

METHOD FB_init (
 [input] bInitRetains : BOOL,
 [input] bInCopyCode : BOOL) : BOOL

Inputs

bInitRetains BOOL
bInCopyCode BOOL

Returns

BOOL

Properties

Busy 

PROPERTY Busy : BOOL

Similarily to the object implementation of Busy, this property returns TRUE, if the UnitStateMachine is currently working. StateMachines are busy if they are in a valid active state and have a sequence associated with it.

Property Value

BOOL

Done 

PROPERTY Done : BOOL

If the UnitStateMachine is in idle state, often mentioned as "not on error and not busy" then this property returns TRUE. This object returns Busy TRUE if the UnitStateMachine is currently working. StateMachines are busy if they are in a valid active state including an initialized Sequence.

Property Value

BOOL

Error 

PROPERTY Error : BOOL

This property returns TRUE if a fault occured within a sequence or the initialization phase of an object, respectively. If this property returns TRUE, one of the ErrorMessage methods gives insight about the origin of the fault.

It is also possible to distinguish between initialization errors and sequence errors by checking the exact internal state of the object using the State method.

Property Value

BOOL

StateAsString 

PROPERTY StateAsString : ZCore.ZString

Property Value

ZString

Methods

ErrorId 

METHOD ErrorId () : UDINT

Returns the error code of the first error source for this object. The method recursively goes down the error stack until the initial source of error of this object can be found. For performance reasons, the error stack is not cleared when the error state is reset. So this method should always be used in conjunction with Error.

Returns

UDINT

ErrorMessage 

METHOD ErrorMessage () : ZCore.ZString

Returns the error description of the first error source for this object. The method recursively goes down the error stack until the initial source of error of this object can be found. For performance reasons, the error stack is not cleared when the error state is reset. So this method should always be used in conjunction with Error.

Returns

ZString

ErrorSource 

METHOD ErrorSource () : ZCore.IError

This method returns the direct error source of this object. This method can then be used to retrieve the actual error source by using the method of the returned IError interface.

Returns

IError

IsTransitionAllowed 

METHOD IsTransitionAllowed (
 [input] state : INT) : BOOL

The state machine controls all transitions and checks if a specific transition is allowed. When changing from one state to another, this method checks if this is allowed and returns TRUE. For example a direct change from state init to state automatic is not possible, in this case this method returns FALSE.

Inputs

state INT

state in which a transition is planned

Returns

BOOL

SetAutomaticSequence 

METHOD SetAutomaticSequence (
 [input] sequence : REFERENCE TO ZAux.Sequence)

For every state, it is possible to set a specific sequence. A Zeugwerk Template unit does this in its FB_init initialization, for every default active state This method sets the Sequence for its UnitStateMachineState.Automatic state.

Inputs

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetBootSequence 

METHOD SetBootSequence (
 [input] sequence : REFERENCE TO ZAux.Sequence)

For every state, it is possible to set a specific sequence. A Zeugwerk Template unit does this in its FB_init initialization, for every default active state This method sets the Sequence for its UnitStateMachineState.Automatic state.

Inputs

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetFaultReactionSequence 

METHOD SetFaultReactionSequence (
 [input] sequence : REFERENCE TO ZAux.Sequence)

For every state, it is possible to set a specific sequence. A Zeugwerk Template unit does this in its FB_init initialization, for every default active state This method sets the Sequence for its UnitStateMachineState.Automatic state.

Inputs

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetFaultSequence 

METHOD SetFaultSequence (
 [input] sequence : REFERENCE TO ZAux.Sequence)

For every state, it is possible to set a specific sequence. Usually A Zeugwerk Template unit does not have any sequence for default inactive states (e.g. Fault, Idle, Init), but these can be set in the FB_init method of the unit. Sequences in inactive states are usefull for observing things when the application/controled system is not active or not doing anything and waiting for the next action. This method sets the Sequence for its UnitStateMachineState.Fault state.

Inputs

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetGoHomeSequence 

METHOD SetGoHomeSequence (
 [input] sequence : REFERENCE TO ZAux.Sequence)

For every state, it is possible to set a specific sequence. A Zeugwerk Template unit does this in its FB_init initialization, for every default active state This method sets the Sequence for its UnitStateMachineState.Automatic state.

Inputs

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetIdleSequence 

METHOD SetIdleSequence (
 [input] sequence : REFERENCE TO ZAux.Sequence)

For every inactive state, it is possible to set a specific sequence. Usually A Zeugwerk Template unit does not have any sequence for default inactive states (e.g. Fault, Idle, Init) but these can be set in the FB_init method of the unit. Sequences in inactive states are usefull for observing things when the application/controled system is not active or not doing anything and waiting for the next action.

In idle state this sequence can be used to handle all safety door opening requests for example

This method sets the Sequence for its UnitStateMachineState.Idle state.

Inputs

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetInitSequence 

METHOD SetInitSequence (
 [input] sequence : REFERENCE TO ZAux.Sequence)

For every inactive state, it is possible to set a specific sequence. Usually A Zeugwerk Template unit does not have any sequence for default inactive states (e.g. Fault, Idle, Init) but these can be set in the FB_init method of the unit. Sequences in inactive states are useful for observing things when the application/controlled system is not active or not doing anything and waiting for the next action. This method sets the Sequence for its UnitStateMachineState.Init state.

Inputs

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetLogger 

METHOD SetLogger (
 [input] logger : ZCore.ILogger)

Use this function to enable logging for this statemachine instance.

Inputs

logger ILogger

Interface to a Zeugwerk Framework compatible logging object

SetName 

METHOD SetName (
 [input] name : ZCore.ZString)

Sets the name of the Statemachine As default, in a Zeugwerk Template here the name of the Unit is set in FB_init

Inputs

name ZString

name of the statemachine as string

SetSequence 

METHOD SetSequence (
 [input] state : UnitStateMachineState,
 [input] sequence : REFERENCE TO ZAux.Sequence)

Links the state of the statemachine to a sequence, which is executed once the statemachine has transitioned into this state To make a transition into a states, the UnitStateMachine state has to be in UnitStateMachineState.Idle.

Note

state has to be greater than 0 and equal or smaller than MaxStates. The first state index of Userdefined States has to be equal or greater than UnitStateMachineState.Last. UnitStateMachineState.Halt and UnitStateMachineState.Halt are special states, which can not be mapped to a sequence. Trying to do so results in booting error!

Inputs

state UnitStateMachineState

Predefined or userdefined state of the statemachine

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible Sequence

SetState 

METHOD SetState (
 [input] state : UnitStateMachineState) : BOOL

This method can be used to force the statemachine into a specific state. In contrast to TransitionAsync the change is abruptly and will not stop an optionally already running sequence. In contrast to SetState this method only accepts states defined in UnitStateMachineState.

This method should only be used to set the initial state of the statemachine and not for controlling a sequential flow. For the later purpose, TransitionAsync should be used, which performs a "clean" transition from one state to another.

In the Zeugwerk Template this method is used to set the initial state to Boot.

Inputs

state UnitStateMachineState

enumeration which defines the Zeugwerk Template standard states

Returns

BOOL

SetStoppedSequence 

METHOD SetStoppedSequence (
 [input] sequence : ZCore.ISequence)

For every inactive state, it is possible to set a specific sequence. Usually A Zeugwerk Template unit does not have any sequence for default inactive states (e.g. Fault, Idle, Init) but these can be set in the FB_init method of the unit. Sequences in inactive states are usefull for observing things when the application/controled system is not active or not doing anything and waiting for the next action. This method sets the Sequence for its UnitStateMachineState.Stopped state.

Inputs

sequence ISequence

Zeugwerk compatible Sequence implementing the ISequence interface for the UnitStateMachineState.Stopped

SetStopSequence 

METHOD SetStopSequence (
 [input] sequence : ZCore.ISequence)

For every state, it is possible to set a specific sequence. A Zeugwerk Template unit does this in its FB_init initialization, for every default active state This method sets the Sequence for its UnitStateMachineState.Automatic state.

Inputs

sequence ISequence

Zeugwerk compatible Sequence implementing the ISequence interface for the UnitStateMachineState.Stop

SetUserdefinedActionSequence 

METHOD SetUserdefinedActionSequence (
 [input] stateIndex : INT,
 [input] name : ZCore.ZString,
 [input] sequence : REFERENCE TO ZAux.Sequence)

Adds a userdefined action for the Zeugwerk Template UnitStateMachine. Actions can be used to execute sequences when the statemachine is in any non-active state

  • Init
  • Fault
  • Stopped
  • Idle

This is useful if a unit has an error or can not be homed for whatever reason and for example someone wants to call a sequence for opening a clamping system.

Note

stateIndex has to be greater or equal to Last and smaller than MaxStates. Calling this method with with an invalid stateIndex results in a BootingError.

Inputs

stateIndex INT

Index of a userdefined action, has to be equal or greater than UnitStateMachineState.Last

name ZString

Name of the sequence as it is displayed in StateAsString, if the parameter is set this will internally call sequence.SetName(name)

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible sequence object

SetUserdefinedStateSequence 

METHOD SetUserdefinedStateSequence (
 [input] stateIndex : INT,
 [input] name : ZCore.ZString,
 [input] sequence : REFERENCE TO ZAux.Sequence)

This method adds a userdefined state and a sequence to the statemachine. Its similar to SetSequence but this method sets the UserdefinedState flag per default.

Note

stateIndex has to be greater or equal to Last and smaller than MaxStates. Calling this method with with an invalid stateIndex results in a BootingError.

Inputs

stateIndex INT

index to a userdefined state

name ZString

Name of the sequence as it is displayed in StateAsString, if the parameter is set this will internally call sequence.SetName(name)

sequence REFERENCE TO Sequence

Interface to a Zeugwerk Framework compatible sequence object

State 

METHOD State () : UnitStateMachineState

Return the current state index of the state machine. The method returns 0 if an invalid state has been set

Returns

UnitStateMachineState

StateDecoded 

METHOD StateDecoded (
 [input] state : INT) : ZCore.ZString

Allows to map a state enumeration to strings, which are then used for logging.

Inputs

state INT

state as definied with UnitStateMachineState or a userdefined state/action.

Returns

ZString

TraceErrorStack 

METHOD TraceErrorStack (
 [input] trace : ZCore.IErrorTrace)

This method is used internally when recording an error trace.

Inputs

trace IErrorTrace

TransitionAsync 

METHOD TransitionAsync (
 [input] startToken : ZCore.IStartToken,
 [input] state : UnitStateMachineState) : BOOL

to state, but only if the transition is allowed.

The state change is not performed instantly, but only in the next call of the Cyclic method, which is usually automatically called by an object manager or the parent of this object.

If the transition is successfully executed this method will return TRUE otherwise FALSE.

Inputs

startToken IStartToken
state UnitStateMachineState

enumeration which defines the Zeugwerk Template standard states

Returns

BOOL