Read Captured Position Reads a captured position value from an axis or encoder. Details      Remarks

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

	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 Encoder is the axis or encoder to read.
	Ret Vect indicates the destination for the return data generated by this VI. Available return vectors include return data to the host (0xFF), return data to a variable (0x01 through 0x78), return data to an indirect variable (0x81 through 0xF8), and do not return data (0). 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.
	Captured Position is the position value captured when the corresponding high-speed capture input went active.
	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 Read Captured Position VI returns the value in the high-speed capture register of the axis or encoder selected. This value was captured when an enabled high-speed capture input went active.

High-speed capture functionality is performed by the encoder resources themselves. When this VI is sent to an axis, the value returned is actually from the mapped encoder resource.

For buffered high-speed capture, the captured positions are stored in a buffer. Use Read Buffer to read the captured positions.

Refer to the Enable High-Speed Capture and Read High-Speed Capture Status VIs for more information about the high-speed capture inputs and typical applications.

Note  For closed-loop stepper systems in which the encoder counts-per-revolution differs from the steps-per-revolution, the captured position is in encoder counts.

Remarks

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

NI 73xx Controller Considerations

The following list includes considerations you must make when you are using this VI with a 73xx motion controller:

• NI 73xx controllers do not support multiple simultaneous high-speed captures per axis.

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 supports multiple simultaneous high-speed captures per axis.
  
  To use this VI to read multiple high-speed capture positions on an axis, set the upper four bits of the resource ID to the following.
  
  

  Type	Value
  Primary HS Capture	0X0
  Secondary HS Capture	0XA0

  
  
  For example, to enable the primary high-speed capture status on axis 1, set the resource ID to 0X01. To enable the secondary high-speed capture status on axis 1, set the resource ID to 0XA1.