NI-FGEN Standard Function Generator Express VI

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NI-FGEN Standard Function Generator Express VI

Configures and runs National Instruments signal generators using NI-FGEN in Standard Function output mode.

The NI 5404 frequency generator is not supported.

You must place at least two NI-FGEN Express (Standard Functions) Vis on the block diagram for successful function generation. Select Start generation for the Generation Mode in the first Express VI to start the function generation. Select Stop generation for the Generation Mode in the final Express VI to abort function generation and close the NI-FGEN device handle.

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Dialog Box Options

Parameter	Description
Configuration	Contains the following options: Device—Specifies the signal generator used. This ring control lists all NI signal generators installed on this computer that can be used by this Express VI. If you re-open the VI and the selected signal generator is dimmed, it is no longer available. Disable output on close—Specifies the behavior of the output enable relay when the device resources to the selected signal generator are released. Disabling the output grounds the output connector; otherwise, a constant DC voltage representing the last data point generated before stopping the waveform may be present. Generation Mode—Specifies the generation mode of the signal generator. Contains the following options: Start generation—Configures the signal generator to generate the waveform continuously and starts the generation. In this mode, the Express VI returns immediately after starting the generation. To stop the generation, drop another instance of the Express VI on the block diagram, select the same signal generator, and configure it to Stop generation. Stop generation—Use this mode to stop a continuous generation that was started by another instance of this Express VI that was configured to Start generation. Function Setup—Configures the characteristics of the function to generate. Contains the following options: Type—Specifies the standard waveform for the function generator to produce. Frequency (Hz)—Specifies the frequency of the standard waveform. Duty cycle (%)—Specifies the duty cycle of the square waveform. This value is the percentage of time the square waveform is high in a cycle. Amplitude (Vpk)—Specifies the amplitude of the standard waveform. This value is the amplitude at the output terminal. For example, to produce a waveform ranging from -5.00 to +5.00 V, set Amplitude (Vpk) to 5.00. DC offset (V)—Specifies the DC offset of the standard waveform. This value is the offset from ground to the center of the waveform. For example, to configure a waveform with an amplitude of 10.00 V to range from 0.00 V to +10.00 V, set DC offset (V) to 5.00. Start phase (deg)—Specifies the horizontal offset of the standard waveform. Output impedance—Specifies the output impedance of the signal generator. Load impedance—Specifies the load impedance. Using this control allows the signal generator to produce the correct output signal for the most common applications: high (>1 MΩ) load impedance; or matched output and load impedance.
Trigger and Timing	Contains the following options: Trigger type—Specifies the type of trigger to use for starting waveform generation. Selecting an Immediate trigger starts waveform generation as soon as all configuration settings are applied. Trigger source—Specifies the trigger source. The signal generator waits for the specified trigger to start waveform generation. Edge—Specifies whether to trigger on a rising edge or a falling edge of the trigger signal. Reference clock source—Specifies the source of a 10 MHz reference clock signal. The function generator uses this reference clock source to derive output frequencies.

Parameter

Description

Configuration

Contains the following options:

Device—Specifies the signal generator used. This ring control lists all NI signal generators installed on this computer that can be used by this Express VI. If you re-open the VI and the selected signal generator is dimmed, it is no longer available.
Disable output on close—Specifies the behavior of the output enable relay when the device resources to the selected signal generator are released.

Disabling the output grounds the output connector; otherwise, a constant DC voltage representing the last data point generated before stopping the waveform may be present.
Generation Mode—Specifies the generation mode of the signal generator. Contains the following options:
- Start generation—Configures the signal generator to generate the waveform continuously and starts the generation. In this mode, the Express VI returns immediately after starting the generation. To stop the generation, drop another instance of the Express VI on the block diagram, select the same signal generator, and configure it to Stop generation.
- Stop generation—Use this mode to stop a continuous generation that was started by another instance of this Express VI that was configured to Start generation.
Function Setup—Configures the characteristics of the function to generate. Contains the following options:
- Type—Specifies the standard waveform for the function generator to produce.
- Frequency (Hz)—Specifies the frequency of the standard waveform.
- Duty cycle (%)—Specifies the duty cycle of the square waveform. This value is the percentage of time the square waveform is high in a cycle.
- Amplitude (Vpk)—Specifies the amplitude of the standard waveform. This value is the amplitude at the output terminal. For example, to produce a waveform ranging from -5.00 to +5.00 V, set Amplitude (Vpk) to 5.00.
- DC offset (V)—Specifies the DC offset of the standard waveform. This value is the offset from ground to the center of the waveform. For example, to configure a waveform with an amplitude of 10.00 V to range from 0.00 V to +10.00 V, set DC offset (V) to 5.00.
- Start phase (deg)—Specifies the horizontal offset of the standard waveform.
- Output impedance—Specifies the output impedance of the signal generator.
- Load impedance—Specifies the load impedance. Using this control allows the signal generator to produce the correct output signal for the most common applications: high (>1 MΩ) load impedance; or matched output and load impedance.

Trigger and Timing

Contains the following options:

Trigger type—Specifies the type of trigger to use for starting waveform generation. Selecting an Immediate trigger starts waveform generation as soon as all configuration settings are applied.
Trigger source—Specifies the trigger source. The signal generator waits for the specified trigger to start waveform generation.
Edge—Specifies whether to trigger on a rising edge or a falling edge of the trigger signal.
Reference clock source—Specifies the source of a 10 MHz reference clock signal. The function generator uses this reference clock source to derive output frequencies.

Block Diagram Inputs

Parameter	Description
error in	Describes error conditions that occurred prior to running this Express VI.

Block Diagram Outputs

Parameter	Description
error out	Contains error information. If error in indicates that an error occurred before this Express VI, error out contains the same error information. Otherwise, it describes the error status that this Express VI produces.

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