PTOEnhancedHome Function Block

Function Description

The PTOEnhancedHome function block commands a move to the reference position similar to the PTOHome function block.

Homing is carried out using one of the following methods:

oShort Cam

oLong Cam Positive

oLong Cam Negative

oShort Cam with Positive Limit

oShort Cam with Negative Limit

oShort Cam with Marker(Z)

Additionally, the PTOEnhancedHome function block provides 2 additional features:

Origin compensation After reaching and stopping at the reference position, the axis moves by a set number of compensation pulses to a compensation position.

Origin offset Once the axis has reached the compensation position, the current position is set to the value defined in the input OffsetPosition.

The following diagram illustrates the compensation move, which is carried out once the axis has reached the reference position:

For example, in the diagram above, if the position of point A = -4000, if needed, you can set this value to 0 using the origin offset feature.

NOTE:

oThe frequency represents the velocity. The 2 terms are equivalent.

oIf the target velocity cannot be reached before reaching the compensation position, the axis velocity will follow a triangular profile.

The PTOEnhancedHome function block requires the Origin input to be configured, otherwise the function block sets the Error output.

As soon as the value of the input OffsetPosition has been set, the output Done is set to TRUE.

Graphical Representation

IL and ST Representation

To see the general representation in IL or ST language, refer to the chapter Function and Function Block Representation.

I/O Variables Description

The following table describes the input variables:

Inputs	Type	Comment
PTO_REF_IN	PTO_REF	Reference to the PTO channel. To be connected to the PTO_REF of the PTOSimple or the PTO_REF_OUT of the Administrative or Motion output pins function blocks.
Execute	BOOL	On rising edge, starts the function block execution. When FALSE, resets the outputs of the function block when its execution terminates.
HighVelocity	DWORD	Value of the maximum initial Homing search velocity in Hz. Range: 1 Hz...100 kHz LowVelocity ≤ HighVelocity ≤ Maximum frequency of the output
LowVelocity	DWORD	Value of the maximum final Homing approach velocity in Hz. Range: 1 Hz...100 kHz LowVelocity ≤ HighVelocity
HomingType	PTO_HOMING_TYPE	Defines the homing type.
Direction	PTO_DIRECTION	Direction of the move.
CompVelocity	DWORD	Target velocity during the compensation move in Hz. Range: 1...Maximum frequency of the output
CompDirection	PTO_DIRECTION	Direction of the compensation move.
CompAcc	DWORD	Acceleration in Hz/ms or in ms (according to configuration). Range Hz/ms: 1...Acc. max Range ms: Acc. max...65000 (Maximum Software Limit)
CompDec	DWORD	Deceleration in Hz/ms or in ms (according to configuration). Range Hz/ms: 1...Dec. max Range ms: Dec. max...65000 (Maximum Software Limit)
Compensation	DWORD	Distance of the move in number of compensation pulses. Range: 1...4,294,967,295
OffsetPosition	DINT	Value of the offset position.

NOTE: The acceleration and deceleration ramps cannot exceed 2,147,483,647 pulses.

The following table describes the output variables:

Outputs	Type	Comment
PTO_REF_OUT	PTO_REF	Reference to the PTO channel. To be connected with the PTO_REF_IN input pin of the Administrative and Motion function blocks.
Status	PTO_ENHANCEDHOME_STATUS_TYPE	Defines the status of the axis movement.
Done	BOOL	TRUE = indicates that the command is finished. Function block execution is finished.
Busy	BOOL	TRUE = indicates that the command is in progress.
CommandAborted	BOOL	TRUE = indicates that the command was aborted due to another move command. Function block execution is finished.
Error	BOOL	TRUE = indicates that an error was detected. Function block execution is finished.
ErrID	PTOPWM_ERR_TYPE	When Error is TRUE: type of the detected error.

NOTE: For more information about Done, Busy, CommandAborted and Execution pins, refer to General Information on Function Block Management.