MC_Power

Description

This function block requests to enable the drive and close the position loop, or disable the drive and open the position loop. The Status output indicates the state of the position loop. If the position loop is open, the axis command position is set to the actual position of the axis and tracks the actual position.

MC_Power

Figure 7-118: MC_Power

You must be careful if you have more than one instance of MC_Power FB for the same drive, scanned in the same cycle. The problem arises when one instance requests the drive to enable and the other requests the same drive to disable.
To avoid this trap, it is recommended to have only one instance of MC_Power for all of your active programs.

This function or function block returns cached data. See Programming a Dual Core Controller for more information.

Arguments

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

Input

Enable	Description	When this transitions go to high, the control closes the servo loop and sends a command to the drive to enable. When this transitions go to low, the control opens the servo loop and sends a command to the drive to disable.
	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	—
Enable Positive	Description	for future enhancement
	Data type	BOOL
	Range	0, 1
	Unit	n/a
	Default	—
Enable Negative	Description	for future enhancement
	Data type	BOOL
	Range	0, 1
	Unit	n/a
	Default	—
BufferMode	Description	Unused
	Data type	SINT
	Range	[0]
	Unit	n/a
	Default	—

Output

Status	Description	Indicates the enabled/disabled state of the drive
	Data type	BOOL
Busy	Description	for future enhancement – always false
	Data type	BOOL
Error	Description	Indicates an invalid input was specified
	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_Power ST example *)

Inst_MC_Power( CloseLoopReq, Axis1, TRUE, TRUE, 0 );

//Inst_MC_Power is an instance of MC_Power function block

DriveIsOn := Inst_MC_Power.Status; //store the Status output into a user defined variable

Ladder Diagram

MC_Power: LD example

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