Digital Output Express VI

LabVIEW 2015 roboRIO Toolkit Help

Edition Date: June 2015

Part Number: 374999A-01

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Requires: myRIO Toolkit or roboRIO Toolkit

Writes values to one or more digital output channels on the myRIO or the roboRIO.

This Express VI writes one sample each time with the default FPGA personality on the myRIO. This Express VI writes one sample or multiple samples each time with the high-throughput FPGA personality on the myRIO. Visit ni.com/info and enter the Info Code ex6g5a to learn about the myRIO high-throughput FPGA personality.

This Express VI writes one sample each time with the default FPGA personality on the roboRIO. The roboRIO uses a 5 V voltage rail on the DIO port for powering sensors and provides 3.3 V DIO lines for generating digital output signals.

Details  

Dialog Box Options
Block Diagram Inputs
Block Diagram Outputs

Dialog Box Options

ParameterDescription
I/O mode(myRIO Toolkit) Specifies to write one sample or multiple samples. The default is Digital output (1 sample). This option is available only when you use the myRIO high-throughput FPGA personality.
Node nameSpecifies the name of this Express VI. You can also double-click the name of this Express VI on the expandable node to edit the name.
ChannelSpecifies the digital output channel to which to write a value. If the channel you select is set as a digital input channel, this Express VI changes the channel to a digital output channel before writing the value.
Custom channel nameSpecifies a custom name for the digital output channel that you select.
Delete ChannelDeletes the digital output channel that you select. (myRIO Toolkit) If you use the myRIO high-throughput FPGA personality, this option is available only when you specify Digital output (1 sample) for I/O mode.
Add ChannelAdds a new digital output channel to the channel list. You can add up to 12 digital output channels. (myRIO Toolkit) If you use the myRIO high-throughput FPGA personality, this option is available only when you specify Digital output (1 sample) for I/O mode.
Sample rate(myRIO Toolkit) Specifies the sampling frequency of the output signal. Valid values are between 1 kHz and 8 MHz. If you specify a frequency that is invalid, this Express VI coerces the specified value to the nearest valid value when you click the Validate button. This option is available only when you use the myRIO high-throughput FPGA personality and specify Digital output (n samples) for I/O mode.
  • Frequency value—Specifies the value of the sampling frequency. The default is 1.
  • Frequency unit—Specifies the unit of the sampling frequency. The default is kHz.
  • Validate—Validates whether this Express VI can generate the sampling frequency that you specify. If the specified sampling frequency is not valid, this Express VI coerces the specified value to the nearest valid value.
Wait until done?(myRIO Toolkit) Specifies whether this Express VI waits until the write operation completes. If the Wait until done? checkbox contains a checkmark, this Express VI waits until the write operation completes. By default, this checkbox does not contain a checkmark. This option is available only when you use the myRIO high-throughput FPGA personality and specify Analog output (n samples) for I/O mode.
Latency(myRIO Toolkit) Displays the latency between two adjacent signal generation iterations. Refer to the Details section of this topic for more information about latency. This option is available only when you use the myRIO high-throughput FPGA personality and specify Digital output (n samples) for I/O mode.
View CodeDisplays the underlying code of this Express VI.
Connection DiagramShows the I/O connector pinouts on the myRIO or the roboRIO. The highlighted pinouts represent the channels that you configure.

Block Diagram Inputs

ParameterDescription
channel nameSpecifies the value to write to the digital output channel that you select, where channel name is the name of the digital output channel.
error in (no error)Describes error conditions that occur before this node runs.

Block Diagram Outputs

ParameterDescription
error outContains error information. This output provides standard error out functionality.

Digital Output Details

(myRIO Toolkit) The following figure demonstrates the latency when you use the Digital Output Express VI with the myRIO high-throughput FPGA personality to perform n samples write operations.

In the previous figure, the x-axis represents time and the y-axis represents amplitude. The time interval between two adjacent signal generation iterations is latency. In other words, the myRIO does not export signals when latency occurs.

Related Information

1 Sample versus N Samples Modes (myRIO Toolkit)

Generating FPGA Clocks (myRIO Toolkit)

Generating FPGA Clocks (roboRIO Toolkit)

I/O Connectors (myRIO Toolkit)

I/O Connectors (roboRIO Toolkit)

Latency in N Samples Read and Write Operations (myRIO Toolkit)

Power Supply for Peripheral Devices (roboRIO Toolkit)

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