MC_Halt

Description

This function block decelerates an axis to zero velocity. It is a queued single-axis move. The move is complete when the axis reaches zero velocity. It is typically used with Abort at the BufferMode input to terminate a move. To execute a stop that cannot be aborted, see MC_Stop.

MC_Halt

Figure 8-137: MC_Halt

Time Diagram

The example below shows the behavior in combination with a MC_MoveVelocity.

A rotating axis is ramped down with FB2 MC_Halt
Another motion command overrides the MC_Halt command

MC_Halt allows this, in contrast to MC_Stop. The axis can accelerate again without reaching standstill.

MC_Halt: Timing Diagram

This function block starts a motion-related action and therefore stores data for calculations and error checking. Please see Calling Function Blocks Multiple Times in the Same Cycle if you are using a dual-core controller.

Arguments

For more detail on how inputs and outputs work, refer to PLCopen Function Blocks - General Rules

Input

Execute	Description	Requests to queue the move
	Data type	BOOL
	Range	0, 1
	Unit	N/A
	Default	—
Axis	Description	Name of a declared instance of the AXIS_REF library function (for more details, About Axis Name and Number)
	Data type	AXIS_REF
	Range	[1,256]
	Unit	N/A
	Default	—
Deceleration	Description	Trapezoidal: Deceleration rate S-curve: Maximum deceleration
	Data type	LREAL
	Range	—
	Unit	User unit/sec²
	Default	—
JerkIn physics, jerk is the rate of change of acceleration; more precisely, the derivative of acceleration with respect to time	Description	Trapezoidal: 0 S-curve: Constant jerkIn physics, jerk is the rate of change of acceleration; more precisely, the derivative of acceleration with respect to time
	Data type	LREAL
	Range	—
	Unit	User unit/sec³
	Default	—
BufferMode	Description	0 = abort 1 = buffer 2 = blend to active 3 = blend to next 4 = blend to low velocity 5 = blend to high velocity See table in Buffer Modes
	Data type	SINT
	Range	[0,5]
	Unit	N/A
	Default	—

Output

Done	Description	Indicates the move completed successfully. The Command Position has reached the endpoint.
	Data type	BOOL
Busy	Description	High from the moment the Execute input is one-shot to the time the move is ended
	Data type	BOOL
Active	Description	Indicates this move is the active move
	Data type	BOOL
CommandAborted	Description	Indicates this move was aborted
	Data type	BOOL
Error	Description	Indicates an invalid input was specified or the move was terminated due to an error
	Data type	BOOL
ErrorID	Description	Indicates the error if Error output is set to TRUE See table in PLCopen Function Block ErrorID Output
	Data type	INT

Example

Structured Text

(* MC_Halt ST example *)

Inst_MC_Halt( HaltReq, Axis1,100.0, 100.0, 0 );

//Inst_MC_Halt is an instance of MC_halt function block

HaltComplete := Inst_MC_Halt.Done; //store Done output into user defined variable

See also how this function is used in the Hole punch project here

Ladder Diagram

MC_Halt: LD example

[Top]