Read Target Position

NI-Motion VI

Read Target Position

Reads the destination position of the current motion trajectory.

Details     Remarks

Device Compatibility

DeviceCompatibility
7330
Y
7340
Y
7344
Y
7350
Y
7390
Y
NI SoftMotion Controller for CANopen—Accelnet
Y
NI SoftMotion Controller for CANopen—Xenus
Y
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 read.
Retn Vect indicates the destination for the return data generated by this VI. Available return vectors include return data to the host (0xFF), to a variable (0x01 through 0x78), 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.
Target Position is the destination position of the current motion trajectory in counts (servo axes) or steps (stepper axes)
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 Target Position VI returns the destination position of the motion trajectory currently in process. If the axis is stopped, it returns the target position of the last trajectory completed.

This VI differs from the Read Position VI in that it returns the commanded target (destination) position rather than the actual feedback position.

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:

  • Loading a new target position with Load Target Position does not affect the value read until a start motion occurs. When calling Blend Motion, the value read does not reflect the last target position loaded until after the blend occurs.

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 returns the target position loaded regardless of whether the Start Motion VI has been called.
  • The NI SoftMotion Controller returns the target position of individual axes, but does not return the target position loaded by the Load Vector Space Position VI, even if the axis is configured as part of the vector space.

    The NI SoftMotion Controller does not support reading the target position of a vector space.