Analog Input Express VI

LabVIEW 2015 roboRIO Toolkit Help

Edition Date: June 2015

Part Number: 374999A-01

»View Product Info
Download Help (Windows Only)

Requires: myRIO Toolkit or roboRIO Toolkit

Reads values from one or more analog input channels on the myRIO or the roboRIO.

This Express VI reads one sample each time with the default FPGA personality on the myRIO. This Express VI reads 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 reads one sample each time with the default FPGA personality on the roboRIO. The roboRIO uses a 5 V voltage rail on the ANALOG IN port for powering sensors.

Details  

Dialog Box Options
Block Diagram Inputs
Block Diagram Outputs

Dialog Box Options

ParameterDescription
I/O mode(myRIO Toolkit) Specifies to read one sample or multiple samples. The default is Analog input (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 analog input channel from which to read the values.
Custom channel nameSpecifies a custom name for the analog input channel that you select.
Delete ChannelDeletes the analog input channel that you select. (myRIO Toolkit) If you use the myRIO high-throughput FPGA personality, this option is available only when you specify Analog input (1 sample) for I/O mode.
Add ChannelAdds a new analog input channel to the channel list. You can add up to 12 analog input channels for the myRIO. You can add up to eight analog input channels for the roboRIO. (myRIO Toolkit) If you use the myRIO high-throughput FPGA personality, this option is available only when you specify Analog input (1 sample) for I/O mode.
Sample rate(myRIO Toolkit) Specifies the sampling frequency of the input signal. Valid values are between 1 kHz and 50 kHz. 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 Analog input (n samples) for I/O mode.
  • Frequency value—Specifies the value of the sampling frequency. The default is 1.
  • Frequency unit—Shows the unit of the sampling frequency. The value 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.
Samples(myRIO Toolkit) Specifies the number of samples to read. The default is 1,000. Valid values must be greater than 0 and less than or equal to 10,000. This option is available only when you use the myRIO high-throughput FPGA personality and specify Analog input (n samples) for I/O mode.
Latency(myRIO Toolkit) Displays the latency between two adjacent signal acquisition 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 Analog input (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
error in (no error)Describes error conditions that occur before this node runs.

Block Diagram Outputs

ParameterDescription
channel nameReturns the value that this Express VI reads from the analog input channel that you select, where channel name is the name of the analog input channel.
error outContains error information. This output provides standard error out functionality.

Analog Input Details

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

In the previous figure, the x-axis represents time and the y-axis represents amplitude. The waveform in blue represents the signal that the myRIO acquires. The red dotted line represents latency. When latency occurs, the myRIO does not acquire any signal. In other words, the time interval between two adjacent signal acquisition iterations is latency.

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)

WAS THIS ARTICLE HELPFUL?

Not Helpful