FB_Referencing

The Homing class implements standard procedures for referencing an axis.

Syntax:

FUNCTION_BLOCK FB_Referencing EXTENDS FB_Base

Properties

Name	Type	Access	Initial value	Description
Name	STRING	Get, Set	<SourceName>	Specifies the name of the class instance.
FB_Referencing
AttachableMdInterface	I_MdComponent	Get	-	Interface to the machine data component
Enable	BOOL	Get, Set	FALSE	If TRUE, commands are executed directly via FB_ReferencingHmi.
ExternalStates	I_AdaptableSeqExt	Get, Set	NULL	Interface to an object with additional homing procedure steps
Homing	I_Homing	Get, Set	THIS^	Subcategory of homing functions.
InputAbsSwitch	I_InputBase	Get, Set	NULL	I/O object for an absolute switch.
InputNegativeLimitSwitch	I_InputBase	Get, Set	NULL	I/O object for an end position sensor in the negative direction.
InputPositiveLimitSwitch	I_InputBase	Get, Set	NULL	I/O object for an end position sensor in the positive direction.
AbsoluteSwitch¹	BOOL	Set	FALSE	Input value of an absolute position switch Alternatively: `InputAbsSwitch`
FB_Base
BaseState	E_BaseState	Get	eNotHandled	Initialization state of the class instance.
Error	BOOL	Get	FALSE	Class is in an error state.
ResultMessage	I_AppMessage	Get	-	Access to the class-internal EventLogger.
[`PROTECTED`] _Name	STRING	Get	<SourceName>	`.Name` without leading 'fb'.

Methods

Name	Description
Reset()	Resets the error state of the class.
FB_Referencing
DoAbort()	Aborts the currently active referencing.
DoAbsSwitch()	Starts referencing the axis using an absolute position switch.
DoAbsSwitchDetect()	Starts the detection of the position of an absolute position switch.
DoAbsSwitchSequence()	Starts a sequence of DoAbsSwitch() and DoFinish().
DoBlock()	Starts referencing against an end stop.
DoBlockDetect()	Starts the detection of the position at an end stop.
DoBlockSequence()	Starts a sequence of DoBlock(), DoBlockDetect() and DoFinish().
DoFinish()	Starts the termination of homing. Notice This step is essential for successfully completing a homing process.
DoLimitSwitch()	Starts referencing the axis against a limit switch.
DoLimitSwitchDetect()	Starts the detection of the position of a limit switch.
DoLimitSwitchSequence()	Starts a sequence of DoLimitSwitch(), DoLimitSwitchDetect () and DoFinish().
DoSetZero()	Sets the current position of the axis to 0.
FB_Base
GetHMI()	Returns the assigned HMI object. Notice The method is not implemented in the `FB_Base` class. If the method is not overwritten by inheritance, a pseudo variable is always returned.
SetHMI(`ipBase`)	General assignment method for an `FB_BaseHmi` extending class as a local HMI. Notice The method is not implemented in the `FB_Base` class. If the method is not overridden by inheritance, it always fails.
[`PROTECTED`] _QueryNamespace()	Extracts the first part of the instance path as an object namespace.
[`PROTECTED`] _QueryObjectName()	Extracts the last part of the instance path as the object name.

Procedure controlling methods (FB_AdaptableSequence)

Name	Description
HomingStates()	State machine of the homing procedures

Event-driven methods (callback methods)

Name	Description
ExtAdaptSeq()	Dummy method() for use without "ExternalStates"

Possible events

ID	Description	Alarm/Message
4000	Homing not allowed	Alarm
4001	Homing failed	Alarm
4002	Save homing was successful	Message
4003	Save homing was not successful	Message

Interfaces

Type	Description
I_Base	Standard interface on FB_Base.
I_Referencing	Standard interface on FB_Referencing
I_AttachableMdInterface	Interface for containerless machine data components
I_AdaptableSeqExt	Interface for providing external homing procedures
I_Homing¹	Compatibility with the obsolete interface on FB_Homing
I_BaseEmpty	For extension without standard interface.
I_BaseDev	Covers all methods and properties of the base class.

Prerequisites

Development environment	Target platform	PLC libraries to include
TwinCAT >= v3.1.4024.54 (recommended) TwinCAT >= v3.1.4024.42 (required)	PC or CX (x64, x86)	Tc3_PlasticBaseApplication (>= v12.10.2.0)

Further Information

HomingStates()