IVI FGEN Arbitrary Waveform Express VI

LabView Acquire Signals Express VIs

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IVI FGEN Arbitrary Waveform Express VI

Owning Palette: Generate Signals Express VIs

Installed With: LabVIEW SignalExpress

Generates an analog arbitrary signal using an instrument in the Arbitrary Waveform/Function Generator IVI class.

Default values are specific to the hardware and driver specified. The default settings may not be applicable to the measurement you are trying to perform. Click the Initialize button, located on the step's toolbar, at any time to reset the step to the default settings.

To communicate with an instrument, you need to install the instrument-specific driver and create a session name for the instrument.

Dialog Box Options
 Place on the block diagram  Find on the Functions palette

Dialog Box Options

ParameterDescription
Waveform PreviewDisplays a preview of the waveform downloaded to the function generator. The vertical and horizontal graph axes are formatted according to the Sample rate (S/s), Gain, and Offset (V) settings applied to the function generator.
ConfigurationContains the following arbitrary waveform configuration options:
  • Device—Contains the following device options:
    • IVI session name—Specifies the session name to use for this step. This step retrieves possible session names from National Instruments Measurement & Automation Explorer (MAX). You also can create a new session or edit/delete an existing session.
    • Resource descriptor—Specifies the interface and the address of the hardware to associate with the step.
    • Instrument driver—Displays the name of the driver in use.
  • Channel Configuration—Contains the following channel configuration options:
    • Channels—Specifies the physical channels on which data is generated.
    • Enable channel—Specifies whether to enable data acquisition on the selected channel.
    • Input signal—Select the appropriate waveform to generate.
    • Generation Mode—Contains the following generation mode options:
      • Generate continuously—Generates the input signal continuously. If you run the project continuously, the step generates the input signal repeatedly without discontinuities. If you run the project in Run Once mode, the step generates the input signal once.
      • Generate N waveforms—Generates the input signal N times in a non-continuous fashion. If you run the project continuously, the step generates the input signal repeatedly but discontinuously. If you run the project in Run Once mode, the step generates the input signal once. You can use this option if you want the device to generate a start trigger every time the device starts generating the signal.
      • Number of waveforms—Number of times to generate the Input Signal.
    • Output Signal—Contains the following output signal options:
      • Extract from waveform—Specifies whether settings for Sample rate (S/s), Gain, and Offset (V) are extracted from the waveform or specified manually. When you remove the checkmark from the Extract from waveform checkbox, you first must normalize the data points to a range of -1 to +1.
      • Sample rate (S/s)—Specifies the sample rate at which you want the function generator to output arbitrary waveforms.
      • Gain—Specifies the factor by which the function generator scales the arbitrary waveform data. When you create arbitrary waveforms, you first must normalize the data points to a range of -1 to +1. You use this property to scale the arbitrary waveform to other ranges. For example, to configure the output signal to range from -2 to +2 volts, set Gain to 2.
      • Offset (V)—Specifies the value the function generator adds to the arbitrary waveform data. When you create arbitrary waveforms, you first must normalize the data points to a range of -1 to +1. You use this parameter to shift the range of the arbitrary waveform. For example, to configure the output signal to range from 0 to 2 volts instead of -1 to 1 volts, set Offset (V) to 1.
      • Impedance (Ohms)—Specifies the impedance value you want the function generator to use. A value of 0 indicates that the function generator is connected to a high impedance load.
      • Frequency (Hz)—Specifies the frequency at which you want the function generator to produce one cycle of an arbitrary waveform.
TriggerContains the following trigger options:
  • Channel Triggering—Contains the following channel trigger options:
    • Channels—Specifies the physical channels that have a trigger associated with them. Each channel can be triggered independently.
    • Type—Specifies the trigger source to which you want the function generator to respond. The default is Immediate. Contains the following options:
      • Immediate—Does not wait for a trigger of any kind.
      • Internal—Waits for a trigger on the internal trigger input.
      • External—Waits for a trigger on the external trigger input.
      • Software Trigger Function—Waits until the software trigger button specified by the Software trigger source is pressed on the toolbar.
      • Digital—Waits for a trigger on a digital input specified by the trigger source.
    • Internal trigger rate (trig/s)—Specifies the rate at which you want the internal trigger rate of the function generator to generate trigger signals. Internal trigger rate (trig/s) is available only when you select Internal in Type.
    • Software trigger source—[Type: Software] Specifies the trigger source to which you want the instrument to respond. To activate the trigger, click the associated trigger button in the toolbar. Execution waits until you click the associated trigger button in the toolbar. Contains the following options:
      • Trigger A—(Default) Specifies Trigger A as the trigger source.
      • Trigger B—Specifies Trigger B as the trigger source.
      • Trigger C—Specifies Trigger C as the trigger source.
    • Source—[Type: Digital] Specifies the trigger source you want to use. Contains the following options:
      • PXI TRIG0 or VXI TTL0—Waits until it receives a trigger on the PXI TRIG0 line (for PXI instruments) or the VXI TTL0 line (for VXI instruments).
      • PXI TRIG1 or VXI TTL1—Waits until it receives a trigger on the PXI TRIG1 line (for PXI instruments) or the VXI TTL1 line (for VXI instruments).
      • PXI TRIG2 or VXI TTL2—Waits until it receives a trigger on the PXI TRIG2 line (for PXI instruments) or the VXI TTL2 line (for VXI instruments).
      • PXI TRIG3 or VXI TTL3—Waits until it receives a trigger on the PXI TRIG3 line (for PXI instruments) or the VXI TTL3 line (for VXI instruments).
      • PXI TRIG4 or VXI TTL4—Waits until it receives a trigger on the PXI TRIG4 line (for PXI instruments) or the VXI TTL4 line (for VXI instruments).
      • PXI TRIG5 or VXI TTL5—Waits until it receives a trigger on the PXI TRIG5 line (for PXI instruments) or the VXI TTL5 line (for VXI instruments).
      • PXI TRIG6 or VXI TTL6—Waits until it receives a trigger on the PXI TRIG6 line (for PXI instruments) or the VXI TTL6 line (for VXI instruments).
      • PXI TRIG7 or VXI TTL7—Waits until it receives a trigger on the PXI TRIG7 line (for PXI instruments) or the VXI TTL7 line (for VXI instruments).
      • ECL0—Waits until it receives a trigger on the VXI ECL0 line.
      • ECL1—Waits until it receives a trigger on the VXI ECL1 line.
      • PXI Star—Waits until it receives a trigger on the PXI STAR trigger bus.
      • RTSI 0—Waits until it receives a trigger on RTSI line 0.
      • RTSI 1—Waits until it receives a trigger on RTSI line 1.
      • RTSI 2—Waits until it receives a trigger on RTSI line 2.
      • RTSI 3—Waits until it receives a trigger on RTSI line 3.
      • RTSI 4—Waits until it receives a trigger on RTSI line 4.
      • RTSI 5—Waits until it receives a trigger on RTSI line 5.
      • RTSI 6—Waits until it receives a trigger on RTSI line 6.
  • Reference clock source—Specifies the reference clock source you want the function generator to use. The function generator derives the frequencies and sample rates that it uses to generate waveforms from the source you specify. Options include Internal, External, and RTSI Clock. For example, when you set Reference clock source to External, the function generator uses the signal it receives at its external clock terminal as its reference clock.
Execution ControlContains the following execution control options:
  • Start this step after—Makes the step wait until another step has started before executing. You can make the step wait on any other hardware step in the project by selecting the step to wait on from the pull-down menu.

    You can use this option to force an acquisition device to start after a generation device starts. You also can use this option to ensure that a device generating a trigger signal starts after the device receiving the signal, which avoids sending the signal before the receiver is ready.
  • Step to wait for—Lists the possible steps for which this step can wait.
  • Pre-execution delay (ms)—Specifies the amount of time to wait before the step executes. If you configure the step to start after another step, the delay represents the amount of time to wait after the specified step starts.
  • Post-execution delay (ms)—Specifies the amount of time to wait after the step executes.
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