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RIO Developer Essentials Guide for Academia

"RT" target

LabVIEW "myRIO" subpalette showing all available Express VIs

Academic RIO Device Toolkit Express VIs
RT guide

Develop Academic RIO Device applications by writing code exclusively for the RT target, and use Express VIs to access the wide variety of I/O devices implemented by the default Device FPGA personality.

LabVIEW RT icon and ABC blocks

Real-Time (RT) programming: Basic procedures
RT guide

Create a new LabVIEW project for the RT target, use the Academic RIO Device Toolkit and default FPGA personality, and deploy a VI as the start-up application.

Screenshot of LabVIEW VI block diagram and front panels of 'RT Main' and 'PC Main'

Make your first RT application
RT procedure

Follow along with this step-by-step tutorial to make a "hello, world!"-like application to experience the advantages of multiple linked VIs running simultaneously on the real-time (RT) target and desktop computer: (1) "RT Main" runs as the RT target start-up VI, blinks the onboard LEDs, and reads the onboard button; these onboard devices physically connect to the FPGA I/O pins which are accessed with the Academic RIO Device Toolkit Express VIs and default FPGA personality, and (2) "PC Main" VI runs on the desktop computer as a user-friendly human-machine interface (HMI) for remote command and control of "RT Main" through the network via shared variables hosted on the RT target.

Screenshot of LabVIEW Project Explorer window for newly-created RT project

Create a new RT project
RT procedure

Set up a LabVIEW project for an RT VI.

Screenshot from LabVIEW Project Explorer showing the "Set as startup" action

Deploy a startup application
RT procedure

Deploy a LabVIEW VI as a 'startup application' that runs automatically immediately after the Academic RIO Device boots up.

LabVIEW RT icon and FPGA icon

RT programming: FPGA personalities
RT guide

The FPGA "personality" (bitstream configuration file) determines how the RT target interacts with peripheral devices. The personality can also implement custom functionality.

Screenshot of I/O Monitor; Analog Output 0 generates a sinewave and Analog Input 0 displays the sine wave

I/O Monitor
RT procedure

Interactively set output values and monitor input values on the Academic RIO Device MXP and MSP connector signals to quickly test your connected peripheral devices without creating a VI. Note: The NI ELVIS III does not have an I/O Monitor at this time.

LabVIEW RT icon and key, clock, and apps icons

RT procedures: System administration
RT guide

Set the administrator password to secure your Academic RIO Device system, adjust the system time and date, and manage the installed software set add-ons.

Screenshot of "Change Password" button for "admin" account

Set the password for the system administrator ("admin") user
RT procedure

Secure your Academic RIO Device system from unauthorized access by setting the password for the "admin" user and removing all permissions from the "everyone" group.

Screenshot of LabVIEW Real-Time Software Wizard displaying currently installed and available software sets

Manage the Academic RIO Device software set add-ons
RT procedure

You will need to enable some software set add-ons to make some built-in LabVIEW VIs work properly on the RT target, for example, 'SMTP client with SSL support' (for secure email) and 'HTTP Client with SSL Support' (for secure HTTP).

Screenshot of NI MAX "Time Settings" tab

Set RT system time and date from a browser
RT procedure

Browse directly to the Academic RIO Device network address to use the Web-Based Monitoring and Configuration tool. Note: The NI ELVIS III does not have the Web Interface for modifying these settings. Use NI Measurement and Automation Explorer (NI MAX) to modify these settings instead.

Screenshot of web browser and "Time Settings" tab

Set RT system time and date from NI MAX
RT procedure

Use the NI Measurement & Automation Explorer (NI MAX) application.

LabVIEW PC block diagram snippet: Get PC system time and adjust RT system time to match

Set RT system time/date from PC
RT code PC code

Use the "Set Time" function to adjust the RT system time to match the (assumed accurate) PC system time. Restart the RT target to save the current RT time to be reloaded on each reboot of the Academic RIO Device.

LabVIEW RT block diagram snippet: Use TCP to read current time from NIST time server, parse and validate the returned string, update the RT system time accordingly

Synchronize the system clock to a NIST time source
RT code

Synchronize the system clock time based on querying the Internet Time Service (ITS) maintained NIST (National Institute of Standards and Technology): Open a TCP/IP connection to the "Daytime Protocol" port 13, read the 51-character string, parse the string for time and date information, validate the result (look for a server health indicator and a "magic string"), and then adjust the system time.

LabVIEW RT icon and file icon

RT procedures: File system
RT guide PC guide

Connect to the Academic RIO Device file system through your browser with "Web-Based Monitoring and Configuring" or by mounting the file system as a drive on your host PC with WebDAV.

Screenshot of browser showing Academic RIO Device file index

Connect to the Academic RIO Device file system with a web browser
RT procedure PC procedure

View the Academic RIO Device file system through your web browser; files may be downloaded with this technique, too.

Windows Explorer window showing myRIO file system as a mapped network drive

Connect to the Academic RIO Device file system with WebDAV
RT procedure PC procedure

Mount the Academic RIO Device file system as a network drive on your Windows, Mac OS, or Linux system, and then directly manipulate the files as you would any other files on your system.

LabVIEW RT block diagram snippet: Open a datalog file, get onboard accelerometer measurement, log the measurement to a file, and close the file

Headless datalogger and file I/O
RT code

Monitor process variables and sensor measurements, timestamp them, and log them to a file, and then remote access the datalog file through the network with WebDAV, web browser, or VI running on a PC host.

LabVIEW RT block diagram snippet: Timed-loop structure

RT programming: Timed loops
RT guide

A "timed loop" is a while-loop structure that executes at a precise user-specified rate. Timed loop are particularly useful for process control loops that demand a reliable update rate.

LabVIEW RT block diagram snippet: Timed loop (deterministic process loop) with loop time measurement indicator and LED blinker

Timed loop
RT code

Use the "Timed Loop" to create a deterministic process loop, i.e., a loop that runs with a precisely-defined time per iteration.

LabVIEW RT block diagram: Measure the number of elapsed RT ticks per loop iteration

Measure loop iteration time
RT code

Use the "Tick Count" function to measure the total elapsed time per iteration of a process loop.

LabVIEW RT icon and exclamation point icon

RT programming: Interrupts
RT guide

Use an onboard timer or an external event interrupt request (IRQ) to immediately execute a task.

LabVIEW RT block diagram snippet: Create a digital input transition IRQ (interrupt request), associate with a callback VI

Externally-triggered action using interrupt request (IRQ)
RT code

Run a callback VI each time that a digital input transition or an analog input voltage threshold crossing generates an interrupt request (IRQ).

LabVIEW RT block diagram snippet: Create a timer IRQ (interrupt request), associate with a callback VI

Timer-driven background process using interrupt request (IRQ)
RT code

Run a callback VI each time that an FPGA-based interval timer generates an interrupt request (IRQ).

Diagram showing communication pathways three process loops on the RT target

RT inter-process communication
RT guide

Exchange data between process loops running in parallel on the RT target.

LabVIEW RT block diagram snippet: Process Loop #1 writes an indicator, Process Loop #2 reads the indicator value with a local variable

Local variable (RT)
RT code

Use a local variable (front-panel indicator) to communicate between two parallel process loops contained within the same VI, and use a local variable to stop parallel loops with one "stop" button.

LabVIEW RT block diagrams: VI #1 writes a global variable, VI #2 reads the same global variable

Global variable (RT)
RT code

Use a global variable to communicate between two parallel process loops contained within different VIs under the same target, and use a global variable to stop parallel loops with one "stop" button.

LabVIEW RT block diagram snippet: Read a single-process shared variable in one process loop that was written by another process loop

Single-process shared variable (SPSV)
RT code

A single-process shared variable (SPSV) behaves like a global variable that links deterministic and non-deterministic process loops, effectively shielding the deterministic loop from elements that contribute jitter.

LabVIEW RT block diagram snippet: Functional global variable subVI with unitialized while-loop shift register and case structure

Functional global variable (FGV)
RT code

Use a functional global variable (FGV) to communicate between two parallel process loops contained within different VIs under the same target, and use a FGV to stop parallel loops with one "stop" button. The "functional" nature of the FGV means that you can create additional functionality beyond that of a basic global variable, e.g., counting and calculations that operate on the stored value.

LabVIEW RT block diagram: for-loop structure enqueues 10 integers, then another for-loop structure dequeues the same elements

Queue
RT code

Use a queue to send messages and data between two or more parallel process loops contained within a VI or other VIs. Queues also serve as the foundation for the "Queued State Machine" design pattern.

LabVIEW RT block diagram snippet: Process Loop #1 writes a channel wire, Process Loop #2 reads the channel wire

Channel wire
RT code

Use a channel wire to communicate between two (or more) parallel process loops contained within the same VI, and use a channel wire to stop parallel loops with one "stop" button. Requires LabVIEW 2016 or later version.

Diagram showing communication pathways three process loops on the FPGA target

FPGA inter-process communication
RT guide

Exchange data between process loops running in parallel on the RT target.

Diagram showing communication pathway between PC host and RT target

RT/host inter-target communication
RT guide PC guide

Transfer data, commands, and status between the RT target and a host system.

LabVIEW FPGA block diagram snippet: RT VI operates the FPGA front panel

Programmatic front-panel communication with RT
FPGA code RT code

The RT VI operates (writes) the front-panel controls of the FPGA VI and reads its indicators.

LabVIEW RT icon and sharing icon

RT procedures: Network-published shared variables (NPSVs)
RT guide PC guide

An NPSV behaves like a global variable to connect the RT target and PC host through a network.

Shared variables icons in LabVIEW project

Create a network-published shared variable (NPSV)
RT procedure PC procedure

The network-published shared variable (NPSV) behaves like a global variable to link targets through the network.

Front-panel indicator LED with green bound variable indicator

Bind a PC VI front-panel indicator to a network-published shared variable (NPSV)
RT procedure PC procedure

A quick and easy way for a PC HMI (human-machine interface) VI to observe the state of an RT-hosted network-published shared variable (NPSV) without creating any block diagram code; an alternative to programmatically accessing the NPSV value.

LabVIEW RT block diagram snippet: RT and PC read and write the same network-published shared variables

Network-published shared variable (NPSV)
RT code PC code

A network-published shared variable (NPSV) behaves like a global variable that links process loops residing in two or more network-connected targets.

LabVIEW RT block diagram snippet: RT opens a handle to a network-published shared variable and reads its value

Programmatically access a network-published shared variable (NPSV)
RT code PC code

Use the NPSV programmatic API (application programmer's interface) VIs as an alternative method to a shared variable node.

LabVIEW RT block diagram snippet: PC writes one element to a network stream channel, RT reads the element from the same channel

Send messages through a network stream channel
RT code PC code

Send command and status messages through a low-latency lossless network-based data communication channel between the RT target and PC host system.

LabVIEW RT block diagram snippet: RT writes blocks of data to a network stream channel, PC reads the blocks from the same channel

Stream high-speed data through a network stream channel
RT code PC code

Efficiently transfer blocks of data between the RT and PC by network streams.

LabVIEW RT block diagram snippet: Read an audio frame from FPGA DMA FIFO, process the frame, and write the processed frame back to the FPGA

Stream high-speed data between FPGA and RT with a DMA FIFO
FPGA code RT code

Efficiently transfer blocks of data between the RT and FPGA by direct memory access (DMA) first-in first-out (FIFO) buffers.

LabVIEW RT block diagram snippet: Programmatically set a custom FPGA bitfile; alert the VI to expect myRIO default personality functionality on the custom FPGA bitfile

Augmented default Academic RIO Device FPGA personality and high-precision waveform measurement application example
FPGA code RT code

Load and run a modified version of the default Academic RIO Device personality (FPGA bitfile) augmented by user-defined functionality, for example, to make a high-precision measurement of pulse width.

Diagram showing communication pathways between PC host, RT target, and FPGA target

FPGA/RT and FPGA/host inter-target communication
FPGA guide RT guide PC guide

Transfer data, commands, and status between the FPGA target and a host system (RT or PC).

Elements entering and leaving a queue

RT programming: Queue-based state machines
RT guide PC guide

Queue-based state machines excel at implementing system control, data measurement and processing, and other tasks to respond to inputs from the surrounding physical system and user interface. Learn about three popular design patterns: queued state machine (QSM), queued message handler (QMH), and event-driven producer-consumer loops.

LabVIEW RT block diagram snippet: While-loop structure containing guard clause, "Command Parser" kernel subVI, and queue

Queued state machine
RT code

State machines perform system control, data processing, and any task that involves executing a sequence of activities in response to inputs from the surrounding physical system, the user interface, and other processes within the system. The queued state machine is a particular implementation style that is flexible and versatile, easy to maintain, and computationally efficient.

LabVIEW RT block diagram snippet: System Manager and Code Validator message-handling loops

Queued message handler with multiple process loops
RT code

The queued message handler contains multiple process loops operating independently and in parallel that communicate with each other by sending messages through queues. Each process is a well-defined task implemented by the "Queued State Machine" design pattern. Breaking up the system into self-contained tasks greatly simplifies the design of complex systems.

LabVIEW front panels of the "Home Security System" application: RT target with virtual user interface and PC host remote interface

System controller application example: Home Security System
RT code PC code

Example of a complete RT system controller based on the Queued Message Handler (QMH) design pattern with multiple parallel task loops implementing behaviors with queued state machines (QSMs), various inter-process communication techniques (queues and local variables), and inter-target communication techniques (network-published shared variables (NPSVs) and network streams). The PC host human-machine interface (HMI) can remotely connect to the system through the network, monitor the status of the security system, and control it remotely.

LabVIEW RT icon and satellite dish icon

RT networking: Get connected
RT guide

Set up wired and wireless networks and connect to the Internet.

Photo of a consumer-grade wireless router

Connect to a home wireless router
RT procedure

Connect an Academic RIO Device to a home wireless router to gain access to the Internet. Note: The NI ELVIS III does not have the Web Interface for modifying these settings. Use NI Measurement and Automation Explorer (NI MAX) to modify these settings instead.

Photo of two myRIO devices, one with its orange ad-hoc wireless LED highlighted

Create a wireless ad-hoc network with two or more Academic RIO Devices
RT procedure

Set up one Academic RIO Device to serve as the ad-hoc network host, and then set up additional Devices to join the ad-hoc network. Note: The NI ELVIS III does not have the Web Interface for modifying these settings. Use NI Measurement and Automation Explorer (NI MAX) to modify these settings instead.

Photo of X-HUB Ethernet adapter attached to myRIO device

Create an Internet-capable wired network with PC
RT procedure PC procedure

Connect the Academic RIO Device to a PC with a wired network (Ethernet) and establish the Device's Internet connection by sharing the PC wireless connection to a home wireless router. Note: The NI ELVIS III does not have the Web Interface for modifying these settings. Use NI Measurement and Automation Explorer (NI MAX) to modify these settings instead.

LabVIEW RT icon and IP network icon

RT networking: IP addresses
RT guide PC guide

Display available IP addresses on the PC host and RT target; learn my public Internet IP address by calling a Web service.

Screenshot from NI MAX showing the IP address, subnet mask, gateway address, and DNS server address

Determine the network address of an Academic RIO Device
RT procedure

Use NI MAX to learn the network address (IP address) of your Academic RIO Device.

LabVIEW RT/PC block diagram snippet: Use String To IP to determine all known IP addresses for this target, and then render to human-readable form as strings

Show available IP addresses
RT code PC code

Display all of the network IP (Internet Protocol) addresses at which the RT target or PC host can be reached.

LabVIEW RT icon and email icon

RT networking: email
RT guide

Send email (including attached files) and text messages from the Academic RIO Device.

LabVIEW RT block diagram snippet: RT checks for Internet access and then sends an email composed of recipients, subject line, and message

Send an email or text message
RT code

Use the Simple Mail Transport Protocol (SMTP) to send an email message; send the email to an SMS (Short Message Service) gateway service to forward the email as a text message.

LabVIEW RT block diagram snippet: RT opens a handle to SMTP email session, sets recipients, message, attachments, and headers, then sends the email message

Send a file as an email attachment with high priority (remote webcam photo logger application)
RT code

Use the low-level Simple Mail Transport Protocol (SMTP) VIs create an email, attach a file, and set the email header to flag the message as 'high priority' in the recipient's email application. The illustrative application example captures webcam images at regular intervals and sends them as email attachments.

LabVIEW RT icon and TCP network icon

RT networking: Transmission Control Protocol (TCP)
RT guide

TCP is a reliable connection-based IP networking protocol used between LabVIEW applications as well as other IoT devices.

LabVIEW RT block diagram: Attempt to open an HTTP connection to the Microsoft Network Connectivity Status Indicator (NCSI) web service as indicator of Internet access

Check Internet access (HTTP method)
RT code PC code

Determine whether or not Internet access is available by attempting an HTTP connection to the "Microsoft Network Connectivity Status Indicator" (NCSI) web service.

LabVIEW RT block diagram: Attempt to open a TCP connection to the Microsoft Network Connectivity Status Indicator (NCSI) web service as indicator of Internet access

Check Internet access (TCP method)
RT code PC code

Determine whether or not Internet access is available by attempting a TCP connection to the "Microsoft Network Connectivity Status Indicator" (NCSI) web service.

LabVIEW RT block diagram snippet: Use TCP to read current time from NIST time server, parse and validate the returned string, update the RT system time accordingly

TCP/IP sender and receiver and "TCP ping" application
RT code PC code

Send TCP/IP messages to a destination IP address and port number, listen for incoming TCP/IP messages on a user-defined port, and echo received messages back to the source. Combine the sender and receiver into a single "TCP ping" application to test the communication channel between two network hosts, and illustrate the notifier method to stop parallel loops with one "stop" button.

LabVIEW RT block diagram snippet: Read the onboard accelerometer and pushbutton, convert to JSON string, and write to TCP channel

TCP client-server
RT code PC code

Create a server on the Academic RIO Device that listens for TCP/IP network connection requests from a client running on the PC host, accepts client information including the desired state of the four onboard LEDs, sets the LEDs accordingly, and returns the state of the onboard 3-axis accelerometer and pushbutton.

LabVIEW RT icon and UDP network icon

RT networking: User Datagram Protocol (UDP)
RT guide

UDP is a simple and efficient connectionless IP networking protocol used between LabVIEW applications as well as other IoT devices.

LabVIEW RT block diagram snippet: "UDP Sender" loop sends system name and time and 1-second intervals to the destination IP address and port

UDP sender and receiver and "UDP ping" application
RT code PC code

Send UDP messages to a destination IP address and port number, listen for incoming UDP messages on a user-defined port, and echo received messages back to the source. Combine the sender and receiver into a single "UDP ping" application to test the communication channel between two network hosts, and illustrate the notifier method to stop parallel loops with one "stop" button.

LabVIEW RT block diagram snippet: Read the onboard accelerometer and pushbutton, convert to JSON string, and write to UDP channel

UDP client-server
RT code PC code

Create a server on the Academic RIO Device that listens for UDP datagram messages from a client running on the PC host, accepts client information including the desired state of the four onboard LEDs, sets the LEDs accordingly, and returns the state of the onboard 3-axis accelerometer and pushbutton.

LabVIEW RT icon and globe icon

RT networking: Web services
RT guide

Use the infrastructure of the Web for machine-to-machine exchange of information.

Globe and binoculars icons

Web services overview
RT guide

A "Web service" uses the infrastructure of the Web for machine-to-machine exchange of specific information. The Academic RIO Device can call Web services to retrieve information and can also host Web services to provide information to other systems.

Globe and telephone handset icons

Web services: calling a Web service technical principles
RT guide

Learn the technical principles necessary to create VIs that can call Web services which return information in the form of JSON strings.

LabVIEW RT block diagram snippet: Call an API and parse the returned JSON string

Call a Web service
RT code

Form a query string as a URL, retrieve the JSON string served by the Web service, and parse the JSON string to extract useful information.

Globe and home icons

Web services: hosting a Web service technical principles
RT guide

Learn the technical principles necessary to host a Web service on the Academic RIO Device. Remote clients such as another LabVIEW-based target, an IoT device, or a conventional browser can retrieve sensor measurements and control indicators and actuators using commands obtained from the remote client's request query string.

LabVIEW RT block diagram snippet: Control onboard LEDs from web form data, return system date/time

Host a Web service
RT code

Host a web service on the Academic RIO Device to serve the states of onboard sensors (pushbutton and accelerometer) and system information (date, time, host name, and IP address), and to control the onboard LEDs based on a user-selected LED hex code.