Table Of Contents

IviDmm Read (G Dataflow)

Version:
    Last Modified: October 24, 2017

    Initiates a measurement, waits until the DMM has returned to the Idle state, and returns the measured value.

    spd-note-note
    Note  

    After this node executes, the Reading parameter contains an actual reading or a value indicating that an over-range condition occurred.

    connector_pane_image
    datatype_icon

    error out

    Error information.

    The node produces this output according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.
    datatype_icon

    error in

    Error conditions that occur before this node runs.

    The node responds to this input according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Default: No error

    datatype_icon

    reading

    Returns the measured value. The value you specify for the Measurement Function parameter of the IviDmm Configure Measurement Node determines the units of this parameter as shown in the following table.

    DC Volts volts
    AC Volts volts
    DC Current amperes
    AC Current amperes
    2-Wire Resistance ohms
    4-Wire Resistance ohms
    AC plus DC volts
    AC plus DC Current amperes
    Temperature celcius
    Frequency hertz
    Period seconds
    spd-note-note
    Note  

    If an over-range condition occurs, the Reading parameter contains an IEEE defined NaN (Not a Number) value and the node returns the IVIDMM_WARN_OVER_RANGE (0x3FFA2001) warning code.

    spd-note-note
    Note  

    You can test the measurement value for an over-range condition by calling the IviDmm Is Over-Range Node.

    datatype_icon

    maximum time

    Value you pass indicating the maximum length of time in which to allow the multi-point fetch operation to complete. Express this value in milliseconds. If the operation does not complete within this time interval, the node returns the IVIDMM_ERROR_MAX_TIME_EXCEEDED (0xBFFA2003) error code. When this occurs, you can call IviDmm Abort to cancel the multi-point fetch operation and return the instrument to the Idle state. Defined Values:

    IVIDMM_VAL_MAX_TIME_INFINITE (-1) Wait indefinitely for a timeout.
    IVIDMM_VAL_MAX_TIME_IMMEDIATE (0) Do not wait for a timeout.
    spd-note-note
    Note  

    The Maximum Time parameter affects only this node. It has no effect on other timeout parameters or properties.

    Default: 5000 (ms)

    datatype_icon

    instrument handle out

    The instrument handle that you obtain from the IviDmm Initialize Node. The handle identifies a particular instrument session.

    Default: None

    datatype_icon

    instrument handle

    The instrument handle that you obtain from the IviDmm Initialize Node. The handle identifies a particular instrument session.

    Default: None

    Default Values

    This node applies default values to properties that have not been set by the user under the following conditions:
    1. If the user has not set the value of any property in the IviDmmMultiPoint extension group, the node sets the IviDmm>>Multi-Point Acquisition>>Sample Count [MP] and IviDmm>>Multi-Point Acquisition>>Trigger Count [MP] properties to 1.
    2. If the user has not set the value of the IviDmm>Measurement Operation Options>Auto Zero [AZ] property, the node sets the value of this property to IVIDMM_VAL_AUTO_ZERO_OFF (0).

    Over-range Condition

    If an over-range condition occurs, the Reading parameter contains an IEEE defined NaN (Not a Number) value and the node returns the IVIDMM_WARN_OVER_RANGE (0x3ffA2001) warning code.

    Interchangeability Checking

    This node performs interchangeability checking when the IviDmm>>Inherent IVI Settings>>User Options>>Interchange Check property is set to TRUE. If the IviDmm>>Inherent IVI Settings>>User Options>>Spy property is set to TRUE, you use the NI Spy utility to view interchangeability warnings. You use the IviDmm Get Next Interchange Warning Node to retrieve interchangeability warnings when the IviDmm>>Inherent IVI Settings>>User Options>>Spy property is set to FALSE. For more information about interchangeability checking, refer to the help text for the IviDmm>>Inherent IVI Settings>>User Options>>Interchange Check property.

    Testing Measurement Values

    You can test the measurement value for an over-range condition by calling the IviDmm Is Over-Range Node.

    Simulated Measurements

    The class driver returns a simulated measurement when this node is called and the IviDmm>>Inherent IVI Settings>>User Options>>Simulate property is set to TRUE and the IviDmm>>Inherent IVI Settings>>User Options>>Use Specific Simulation property is set to FALSE. For information on how to configure a simulated measurement, refer to the online help manual.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported

    Web Server: Not supported in VIs that run in a web application


    Recently Viewed Topics