Limiting

This Corefunction is responsible for limiting all axis functions. The type of limitation depends on the drive technology. For example, the torque of electric axes and the pressure of hydraulic axes can be limited. The following function blocks are automatically available internally for axes of type FB_AxisNcBase:

FB_LimitingOutputCoE – DS402 (AX8000)-based TorqueLimiting
FB_LimitingOutputSoE – AX5000-Based torque limiting

This Corefunction is one of the permanently active Corefunctions.

Syntax:

FUNCTION_BLOCK FB_Limiting EXTENDS FB_Corefunction

Properties

Name	Type	Access	Description
InitState	BOOL	Get, Set	The core function is not completely and successfully initialized.
FB_Limiting
Actual	LREAL	Get	Current actual value of the limited variable (torque/pressure)
CmdReference	LREAL	Get, Set	Reference value for scaling the value commanded in a Corefunction. Typically, 100% is specified here.
EffectiveSetpoint	LREAL	Get	The effective value currently being passed to the output.
ExternalMode	BOOL	Get	TRUE as soon as external limiting has been assigned according to the outdated scheme using I_LimitingFb.
IdleValue	LREAL	Get, Set	The idle value for the limitation to which the axis returns after a command.
MaxValue	LREAL	Get, Set	The effective limit of the limit for each command.
Mode	I_LimitingMode	Get	Choice of the operation mode for the limiting function.
Output	I_LimitingOutput	Get, Set	Interface to the output element for the limit.
SetpointCmded	LREAL	Get, (Set)	Setpoint currently specified by the active Corefunction.
SetpointDirection	E_AdaptableDirection	Get, (Set)	The direction currently specified by the active core function.
Transition	I_LimitingTransition	Get	Configuration of the transition between command-based and idle-mode limiting.
ActualTorque¹	LREAL	Get, Set	Current actual torque value of the axis. Alternatively: `Actual`
Activate¹	BOOL	Get, Set	Activates the use of the ActiveValue as an active limit. Alternatively: `Cmd()`
ActiveValue¹	LREAL	Get	Limitation value currently available Alternatively: `EffectiveSetpoint`
ConnectedToDrive¹	BOOL	Get	An internal connection to a drive unit has been established. Alternatively: `MotionParams.HasAutoLimiting`
DefaultFb¹	I_LimitingFb	(Get, Set)	Access to the standard function block for torque limitation if specific handling is used. Alternatively: `SetExternal()`
Direction¹	E_AdaptableDirection	Get, Set	Direction in which the torque limit should act. Alternatively: `SetpointDirection`
NominalValue¹	LREAL	Get, Set	The value specified by a core function Alternatively: `SetpointCmded`
ReferenceValue¹	LREAL	Get, Set	Reference value for the maximum command value of the limit. Alternatively: `CmdReference`
FB_Corefunction
FailedState	BOOL	Get, Set	If IsActivated is TRUE at the same time: Signals the failure of an accepted command. If IsActivated is FALSE at the same time: Signals the rejection of a command.
HasFeedback	BOOL	Get	The core function has responded to a pending command.
IsActivated	BOOL	Get	The core function has an accepted command pending.
IsLocalCmd	BOOL	Get	Signals that the axis is assigned with a command of this core function.
ReadyState	BOOL	Get, Set	The Corefunction is ready for operation, but is not commandable at this time. Possible reasons are: - The axis is not enabled. - Another Corefunction is active. - The Corefunction does not support any commands.

¹Obsolete

Methods

Name	Description
[`INTERN`] Cmd(`bActivate`)	Enables/disables the default limit set by a core function. This method should not be called from within the application.

Name

Description

[INTERN] Cmd(bActivate)

Enables/disables the default limit set by a core function.

This method should not be called from within the application.

Interfaces

Type	Description
I_Corefunction	Standard interface on FB_Corefunction.
I_Limiting	Standard interface to FB_Limiting.
I_LimitingDev	Extended interface for integration with Corefunction.
I_LimitingOutput	Internal implementation to the output interface
I_LimitingFb¹	Interface for the implementation of an external limiting function Alternatively: `/`

¹Obsolete

Example:

// configuration of some settings
iAxisBase.Limiting.CmdReference := 100.0; // %
iAxisBase.Limiting.Mode.Adaptive := TRUE;
iAxisBase.Limiting.Transition.HoldLow := TRUE;

Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT v3.1.4024.71 TwinCAT v3.1.4026.19	PC or CX (x64, x86)	Tc3_PlasticFunctions (>= v12.14.0.0)

Further Information