National Instruments (NI) VeriStand

NI VeriStand's core function is to import and execute dynamic system models from modeling environments like Simulink and LabVIEW on a real-time target. It handles the model compilation, scheduling, and I/O mapping, allowing engineers to focus on test design rather than low-level integration. This enables closed-loop validation where the physical hardware under test interacts with a simulated plant model in real-time.

• Supports models from Simulink, LabVIEW, and ANSYS SCADE.
• Manages model execution rates and task prioritization.
• Provides a framework for custom device models via the VeriStand Custom Device SDK.

The framework provides a centralized interface to configure a wide array of I/O hardware—including analog, digital, PWM, and communication buses like CAN, LIN, and EtherCAT—and map them directly to simulation model variables. This abstracts the hardware details, creating a virtual signal layer that connects the real-time simulation to the Device Under Test (DUT).

• Unified configuration for NI and third-party I/O boards.
• Built-in support for common industrial protocols.
• Simplifies signal routing and scaling between the model and physical pins.

VeriStand includes tools for designing and automating test procedures. Engineers can create stimulus profiles (time-based sequences of input values) and test sequences (scripted sequences of actions) to automate validation workflows. This allows for repeatable execution of complex test cases, including fault injection scenarios.

• Graphical profile editor for creating analog/digital waveform stimuli.
• Test Executive for scripting multi-step sequences with pass/fail logic.
• Enables automated regression testing and continuous integration pipelines.

The system offers robust runtime monitoring and data acquisition. It can log data to disk at high rates, define and trigger alarms based on model or hardware states, and provide calibration interfaces for dynamically tuning parameters in the running model. This is critical for observing system behavior and debugging during tests.

• Streams data to TDMS files for analysis in DIAdem or MATLAB.
• Configurable alarms with email or system notification actions.
• Live tuning of model parameters via XNET or CCP calibration protocols.

For specialized requirements, VeriStand provides a Software Development Kit (SDK) to create Custom Devices. These are software plugins that extend the framework's capabilities to interface with unique hardware, implement custom processing algorithms, or integrate third-party tools like ROS/ROS 2 via a dedicated bridge.

• Enables integration of proprietary sensors, actuators, or communication stacks.
• Allows incorporation of custom real-time logic outside the main model.
• Facilitates connection to robotics middleware for HIL testing of autonomous systems.

VeriStand is designed for deployment on real-time operating systems (like NI Linux Real-Time) to guarantee deterministic execution. It manages the real-time scheduler, ensuring model iterations and I/O operations complete within strict, bounded timeframes. This deterministic behavior is non-negotiable for valid closed-loop HIL testing where timing inaccuracies can invalidate results.

• Deploys to dedicated real-time targets (e.g., PXI controllers).
• Manages worst-case execution time (WCET) for model tasks.
• Provides tools for monitoring and verifying real-time performance.

The dominant application for NI VeriStand is testing Electronic Control Units (ECUs) for vehicles. Engineers use it to create HIL test benches that simulate the rest of the vehicle—engine, transmission, sensors, and network buses—around a physical ECU.

• Key Tests: Functional validation, fault injection (e.g., short circuits), network communication (CAN, LIN, Ethernet), and diagnostic protocol testing.
• Industry Standard: Integral to V-Model development, providing evidence for safety standards like ISO 26262.
• Example: Testing an Engine Control Module's response to simulated sensor failures while monitoring its CAN bus messages and internal states.

Used for validating flight control computers, actuation systems, and avionics under simulated flight conditions. The framework's determinism and support for complex, high-rate models are critical.

• High-Fidelity Simulation: Integrates with models of aerodynamics, propulsion, and inertial measurement units (IMUs).
• Rigorous Standards: Supports testing to DO-178C (software) and DO-254 (hardware) certification requirements.
• Power-HIL (PHIL): Often extended with power amplifiers to test high-power actuators and electromechanical systems in real-time.

Applies to testing the embedded controllers for industrial robots, CNC machines, turbines, and printing presses. VeriStand validates the logic that governs physical motion and process control.

• Complex Kinematics: Simulates multi-axis motor dynamics and gearboxes.
• Protocol Integration: Interfaces with industrial networks like EtherCAT, PROFINET, and Modbus.
• Safety System Validation: Tests Safety PLCs and safety-rated drives by simulating emergency stop scenarios and validating response times.

Critical for developing and testing controllers for inverters, converters, battery management systems (BMS), and grid-tied equipment. Enables Power-Hardware-in-the-Loop (PHIL) testing.

• Electrical Simulation: Uses real-time solvers (like NI's Electromagnetic Transient models) to simulate grid dynamics and power circuits.
• Protection Testing: Validates how controllers respond to grid faults (sags, swells, frequency shifts).
• Renewable Integration: Tests controllers for solar inverters and wind turbine converters under variable, simulated environmental conditions.

Used to validate the embedded systems in infusion pumps, ventilators, surgical robots, and imaging systems. Simulation allows exhaustive testing of safety-critical logic without patient risk.

• Physiological Modeling: Integrates models of human circulatory systems, lung compliance, or tissue interaction.
• Alarm & Safety Logic: Tests device responses to simulated sensor failures or abnormal physiological parameters.
• Regulatory Compliance: Provides traceable test data for FDA submissions under standards like IEC 62304 for medical device software.

Widely adopted in universities and research labs for rapid control prototyping (RCP) and real-time research platforms. Its model integration and data logging accelerate experimental cycles.

• Platform for Innovation: Allows researchers to focus on algorithm development in Simulink or LabVIEW, while VeriStand handles real-time execution, I/O, and data management.
• Custom Workflow Integration: Supports integration with Python scripts and MATLAB for analysis, and ROS/ROS 2 bridges for robotics research.
• Educational Tool: Teaches core concepts of real-time systems, HIL methodology, and controls validation.

dSPACE is a leading commercial provider of integrated hardware and software platforms for real-time simulation, HIL testing, and rapid control prototyping. It is a primary competitor to NI's HIL solutions. The dSPACE ecosystem includes:

• Real-time simulators (SCALEXIO).
• I/O hardware and breakout boxes.
• Software tools for model integration, experiment control, and automation.
• Widespread adoption in automotive and aerospace for validating ECUs and flight controllers.

Simulink Real-Time (formerly xPC Target) is a MathWorks product that compiles Simulink and Stateflow models into optimized C code and executes them on a dedicated target computer running a real-time kernel. It provides a direct path from model-based design to real-time execution for:

• Rapid control prototyping.
• HIL test systems.
• Often used in conjunction with I/O hardware from NI, Speedgoat, or other vendors to form a complete HIL test bench.