Load Blend Factor Loads the blend factor for an axis or vector space. Details

Device Compatibility Device Compatibility 7330 Y 7340 Y 7344 Y 7350 Y 7390 Y NI SoftMotion Controller for CANopen—Accelnet Y NI SoftMotion Controller for CANopen—Xenus Y

	Blend Factor is the blend factor mode and/or dwell time. –1 specifies normal blending (default), 0 specifies a start after the previous move is fully stopped, and values > 0 specify additional dwell time in milliseconds.
	Board ID is a unique number assigned by Measurement & Automation Explorer (MAX) used to send and receive commands and data to or from a specific NI motion controller.
	Axis or Vector Space is the axis or vector space to control.
	Inp Vect indicates the source of the data for this VI. Available input vectors include immediate (0xFF), variable (0x01 through 0x78), or indirect variable (0x81 through 0xF8). Refer to Input and Return Vectors for more detailed information.
	error in (no error) describes error conditions that occur before this VI runs. The default input of this cluster is no error. If an error already occurred, this VI returns the value of error in in error out. The VI runs normally only if no incoming error exists. Otherwise, the VI passes the error in value to error out. The error in cluster contains the following parameters: status is TRUE if an error occurred before this VI was called, or FALSE if not. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. code is a number identifying an error or warning. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. Use the error handler VIs to look up the meaning of this code and display the corresponding error message. source is a string that indicates the origin of the error, if any. Typically, source is the name of the VI in which the error occurred.
	Bd ID Out is provided for flow control. You can string together NI-Motion VIs by wiring the Bd ID Out terminal of one VI to the Board ID terminal of the next VI.
	Resource Output is the Axis, Vector Space, ADC, or Encoder you wired into the VI. Use Resource Output to pass the resource to another VI and/or to display information about the device.
	error out contains error information. If error in indicates an error, error out contains the same error information. Otherwise, it describes the error status that this VI produces. status is TRUE if an error occurred, or FALSE if not. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. code is a number identifying an error or warning. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. Use the error handler VIs to look up the meaning of this code and display the corresponding error message. source is a string that indicates the origin of the error, if any. Typically, source is the name of the VI in which the error occurred.

Using This VI

The Load Blend Factor VI controls how the Blend Motion VI operates. Blending automatically starts a pending move on an axis or vector space when the move in process completes. Exactly when the pending move starts is determined by the loaded blend factor.

A blend factor of –1 causes the pending move to start when the existing move finishes its constant velocity segment and starts to decelerate, as shown in the following figure. This blends the two moves together at the optimum blend point.

If the two moves are at the same velocity, in the same direction, and have matching acceleration and deceleration, they superimpose perfectly without a dip or increase in axis velocity. Vector velocity dips based on the amount of deflection from a straight line.

For a vector move, if all of the axes continue in the same direction, the vector velocity remains constant. But, if one of the axes changes direction, the vector velocity does not remain constant during the transition phase.

A blend factor of zero (0) causes the pending move to start when the existing move fully completes its profile.

Positive blend factors allow for a dwell at the end of the first move before the automatic start of the pending move. The blend factor dwell is programmed in milliseconds.

The maximum value of the positive blend factor depends upon the Sample PID Rate that you set in the Enable Axes VI, because the DSP delays the trajectory generators based on PID sample periods. The formula used to determine the maximum positive blend factor is as follows:

where s is the time in sample periods, t is the positive blend factor value in milliseconds,
and PID is the PID rate in microseconds (62.5, 125, 188, 250, 312, 375, 438, or 500).

If s > 32,767, it is coerced to 32,767 sample periods.

At a Sample PID Rate of 500 µs, the maximum value of the positive blend factor is 16,383 ms and at a Sample PID Rate of 250 µs, the maximum value is 8,192 ms.

If the first move has already completed when the Blend Motion VI is executed, the second move still waits the dwell time before starting.

You can load blend factors to individual axes or to a vector space for coordinated blending of all axes in the vector space. When sent to a vector space, the blend factor is broadcast to all axes in the vector space to change the per-axis blend factors. If you later want to operate an axis independently with a different blend factor, you must execute the Load Blend Factor VI again for that axis.

Note  All axes in a vector space must have the same blend factor. If the blend factors are different on each axis when you execute a Blend Motion VI, an error is generated.