Y_AX_FeedToLength

Y_AX_FeedToLength was designed for use with applications that index forward in one direction, and require on the fly adjustments of the actual index length based on a sensor input that occurs while the axis is moving. This block is a hybrid function block, meaning it uses both types of PLCopen behaviors: Enable and Execute. The reason for this is so the function can monitor for consecutive latches and flag an Error for that condition. The Enable input allows this feature to operate. The Execute input initiates each move.

Parameters:

*	Parameter	Data Type	Description	Default
VAR_IN_OUT
B	Axis	AXIS_REF	Logical axis reference. This value can be located on the Configuration tab in the Hardware Configuration (logical axis number).
V	TriggerData	MC_TRIGGER_REF	Reference to the trigger signal source.
VAR_INPUT
B	Enable	BOOL	The function will continue to execute every scan while Enable is held high and there are no errors.	FALSE
B	Execute	BOOL	Upon the rising edge, all other function block inputs are read and the function is initiated. To modify an input, change the value and re-trigger the execute input.	FALSE
V	DefaultDistance	LREAL	The default product length. This is the distance the axis will travel if a registration mark is not detected.	LREAL#0.0
V	DistanceAfterLatch	LREAL	The desired additional travel distance after the registration mark is detected	LREAL#0.0
B	Velocity	LREAL	Absolute value of the velocity in user units/second.	LREAL#0.0
B	Acceleration	LREAL	Value of the acceleration in user units/second^2 (acceleration is applicable with same sign of torque and velocity)	LREAL#0.0
B	Deceleration	LREAL	Value of the deceleration in user units/second^2 (deceleration is applicable with opposite signs of torque and velocity.)	LREAL#0.0
E	Jerk	LREAL	Not supported; reserved for future use. Value of the jerk in [user units / second^3].	LREAL#0.0
V	MaxCorrection	LREAL	Limits the amount of correction that can be applied. This prevents the machine from trying to make correction that is too large to occur and still make a good product. This is the most amount of change to the DefaultDistance that will be made to any one product index.	LREAL#0.0
V	SensorMinimum	LREAL	The earliest slave position where a sensor position is valid for correction.	LREAL#0.0
V	SensorMaximum	LREAL	The latest slave position where a sensor position is valid for correction.	LREAL#0.0
V	MissedLatchLimit	UINT	The number of consecutive DefaultDistances allowed to occur without seeing a registration mark in the window, and not cause an Error. Valid registration marks will reset the internal counter.	UINT#0
VAR_OUTPUT
B	Valid	BOOL	Indicates that the function is operating normally and the outputs of the function block are valid.
B	Done	BOOL	Set high when the commanded action has completed successfully. If another block takes control before the action is completed, the Done output will not be set. This output is reset when Execute goes low.
B	Busy	BOOL	Set high upon the rising edge of the Execute or Enable input, and reset when Done, CommandAborted, or Error is true.
B	CommandAborted	BOOL	Set high if motion is aborted by another motion command or MC_Stop. This output is cleared with the same behavior as the Done output.
V	ActualSize	LREAL	The actual indexed distance
V	LatchPosition	LREAL	The slave's position in the CamTable when the latch occurred.
V	LimitedCorrection	BOOL	Indicates that the MaxCorrection is limiting the required correction.
V	MissedLatch	BOOL	Flag which indicates that the controller did not find a valid registration mark within the SensorMinimum and SensorMaximum positions.
B	Error	BOOL	Set high if an error has occurred during the execution of the function block. This output is cleared when 'Execute' or 'Enable' goes low.
B	ErrorID	UINT	If Error is true, this output provides the Error ID. This output is reset when 'Execute' or 'Enable' goes low.

Error Description:

See the Function Block ErrorID List.

Example:

Consider a case where the default distance between successive products is 6.2832 units. Let the distance between the sensor (wired to the high speed registration input) and the target position where the product will be processed be 3.1416 units. DistanceAfterLatch = 3.1416.

Needs new graphic? Graphic from MPiec help file included for reference:

MaxCorrection limits the correction if an erroneous registration mark is captured and the calculation results in a large correction distance.

Sensor Minimum and Sensor Maximum provide window in which a registration mark must be seen to be considered a valid registration mark. In this example, the mark is expected around 3.1416 units, therefore a valid window is 2 .0 to 4.5 units. Set the window as small as appropriate for the application.

The FeedToLength function block will position the axis exactly 3.1416 units (DistanceAfterLatch) after the registration mark was detected.

The FeedToLength function block will position the axis exactly 3.1416 units (DistanceAfterLatch) after the registration mark is detected for varying product lengths.