Following Error is the following error trip point in counts. If the following error exceeds this value, the axis is automatically killed. The range is 0 to 32,767 with a default of 32,767 counts. Loading zero (0) is a special case that disables the following error trip functionality.
	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 is the axis 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 Following Error VI sets the maximum allowable following error. Following error is the difference between the instantaneous commanded trajectory position and the feedback position. If the absolute value of this difference exceeds the trip point, an internal kill stop is issued and the axis is disabled.

If this axis is part of a coordinate (vector) space, all other axes are commanded to decelerate to a stop when one axis trips on following error.

This VI is a safety feature used to protect the motion hardware and associated system components from damage when the position error gets excessive due to friction, binding, or a completely stalled motor. It also protects the system in case you load unobtainable values for velocity and/or acceleration.

This feature is available on all servo and closed-loop stepper axes. It has no effect on stepper axes running in open-loop mode. You can completely disable the following error feature by loading a zero (0) value.

Caution  Following error must not be disabled unless the application absolutely requires operating with greater than 32,767 counts of error.

You can monitor following error status with the Read Trajectory Status or Read per Axis Status VIs. A following error trip always sets the Motor Off status. In servo systems, you can further diagnose the cause of the trip by checking the torque limit status with the Read DAC Limit Status VI.

If an axis trips on following error, that axis, or any axes associated through a coordinate space, are prohibited from starting from an onboard program until a start from the host, pause of the onboard program, or run of an onboard program.

In general, a following error trip is considered normal operation and does not generate an error. There are a few cases where an unexpected following error trip generates a modal error: during Find Reference, and while executing a stored program. Refer to the Errors and Error Handling topic for information about errors and error handling.

Remarks

This section includes information about how the behavior of this VI differs among the controllers that support it.

NI SoftMotion Controller Considerations

The following list includes considerations you must make when you are using this VI with the NI SoftMotion Controller:

• The NI SoftMotion Controller does not support loading zero (0) in Following Error to disable the following error.
• For the Inp Vect parameter, the NI SoftMotion Controller supports only the immediate return vector (0XFF).