PCB Assembly Test Toolkit
PCB Assembly Test Toolkit is a software toolkit developed by National Instruments (NI) for electrical functional testing of printed circuit board assemblies (PCBAs). It provides reusable measurement libraries, validation examples, and automated test sequences developed for LabVIEW and TestStand.
The toolkit is intended for engineers developing functional test systems for assembled electronic boards. Its measurement libraries provide interfaces to NI data acquisition, digital multimeter, switching, and communication hardware. Test sequences can be adapted to the electrical characteristics and test requirements of a particular device under test (DUT).[1]
Overview
Electrical functional testing is performed to determine whether an assembled circuit board operates according to specified requirements. Depending on the board, tests may involve power supplies, digital inputs and outputs, communication interfaces, sensors, audio circuits, or other electronic functions.
The PCB Assembly Test Toolkit supplies reusable measurement operations and example test sequences rather than a complete production test system for a specific board.
Users must still define the electrical connections, stimulus conditions, measurement limits, and acceptance criteria for the DUT.
The toolkit includes LabVIEW measurement libraries and automation examples that can be integrated with NI TestStand or adapted for custom test applications.
Measurement libraries
The toolkit contains measurement libraries for use with supported NI instruments and interfaces.
These libraries provide higher-level operations for configuring instruments, generating signals, and acquiring measurements. NI describes an API organization based on initialization, configuration and measurement, and closing operations.[2]
Supported measurement and interface functions depend on the installed drivers and connected hardware.
Data acquisition
NI-DAQmx devices can be used for analog input, analog output, digital I/O, and other supported measurement tasks.
Such functions are applicable to testing signal levels, monitoring power supply outputs, generating control signals, and acquiring sensor responses.
The available channels, voltage ranges, and measurement performance depend on the selected DAQ device.
Digital multimeter and switching
The toolkit supports NI digital multimeter (DMM) instruments through NI-DMM and compatible switching hardware through NI-SWITCH.
DMM measurements can be combined with switching operations to connect an instrument to different points on a circuit board.
This arrangement can reduce the number of dedicated measurement instruments required when several circuit nodes need to be examined sequentially.
Measurement accuracy and switching limitations remain dependent on the instruments and fixture design.
Communication interfaces
The toolkit also provides support for communication hardware using NI-Serial, NI-VISA, and NI-845x drivers.
Depending on the hardware, these interfaces can be used to communicate with devices implementing serial, I2C, or SPI connections.
Communication tests may be used to verify whether a DUT responds to commands, returns expected data, or reports operating status.
Automated test sequences
NI provides example automation sequences implemented with TestStand and the toolkit's measurement libraries.
The examples demonstrate functional test operations for several types of PCBA circuitry.
| Example sequence | Test subject |
|---|---|
| Action Button Test | Response to a button or digital control input |
| Audio Test | Audio-related signal generation and measurement |
| Communication Test | Communication interface operation |
| Digital I/O Test | Digital input and output behavior |
| LED Test | Operation of LED circuits |
| Microphone Test | Microphone-related signal acquisition |
| Power Supply Test | Power supply output characteristics |
| Sensor Test | Sensor output or response |
| Synchronization Example | Coordination of test operations |
These are demonstration sequences. They must be reviewed and modified before being used to establish acceptance criteria for a production DUT.
The source repository also contains a PCBA functional test demonstration showing how the measurement libraries can be used in TestStand.[3]
Supported hardware
According to NI's source repository, the toolkit supports instruments compatible with its supported driver interfaces.
Specific hardware families identified by NI include:
- PXIe, PCIe, and USB data acquisition devices
- PXIe and USB digital multimeters
- PXI and PXIe switching instruments
- CompactDAQ chassis and modules
- TestScale chassis and modules
- NI USB-8452 I2C/SPI interfaces
- NI USB-232 and PXI-843x serial interfaces
The availability of a particular function depends on the hardware model, driver version, and measurement library.
A supported hardware family should not be interpreted as confirmation that every device in that family supports every toolkit function.
Software requirements
The NI GitHub repository documents the following minimum software versions for the source-code-based toolkit:
| Software | Documented minimum version |
|---|---|
| LabVIEW | 2021 SP1 |
| TestStand | 2021 SP1 |
| NI-DAQmx | 2022 Q4 |
| NI-DMM | 2022 Q3 |
| NI-SWITCH | 2022 Q4 |
| NI-Serial | 21.3 |
| NI-VISA | 21.5 |
| NI-845x | 21.3 |
These requirements are taken from the NI source repository. Packaged releases may have different compatibility requirements, which should be checked in the corresponding release documentation.
NI also provides installation and compatibility information for the 2023 Q1 release.[4]
Installation and configuration
The toolkit can be obtained from NI's software download resources or its public GitHub repository.
The repository provides source files, LabVIEW project resources, and example automation sequences.
NI documents two source-based approaches:
- Opening and using the supplied LabVIEW project directly.
- Installing the supplied libraries and metadata as a LabVIEW project template.
Template installation requires files to be placed in the appropriate LabVIEW project template directories. TestStand examples also require the associated sequence and workspace files.
The directory paths depend on whether a 32-bit or 64-bit LabVIEW installation is used.
Before running the examples, the necessary NI drivers must be installed and the selected instruments configured.
Instrument names and channels used by an example may need to be changed to match the connected hardware.
For detailed installation paths and setup instructions, see the NI source repository and toolkit user manual.[3]
Functional test development
A functional test application normally requires more than the supplied measurement VIs.
For a particular PCBA, the test engineer must define:
- Electrical connections between the DUT and test instruments
- Power-up and shutdown procedures
- Signals applied to the DUT
- Measurement points and expected responses
- Pass/fail limits and tolerances
- Timing requirements and test sequence order
- Fault handling and test result reporting
For example, a power supply test may apply input power, measure one or more output rails, and compare the readings against specified limits.
A communication test may send a command to the DUT and evaluate the returned response.
The toolkit's libraries provide building blocks for these operations. The actual measurements and limits must be established from the board's electrical design and test specification.
TestStand can be used to organize the operations into an automated sequence, including setup, execution, result evaluation, and shutdown.
Relationship to other PCBA inspection methods
Electrical functional testing is one part of PCBA quality verification.
It differs from automated optical inspection (AOI), which uses imaging systems to examine visible assembly features such as component placement, orientation, and solder joints.
Functional testing evaluates circuit behavior under defined electrical conditions. An assembly may pass optical inspection but fail functional testing because of a defective component, incorrect programming, or an electrical fault that is not visually apparent.
Conversely, a functional test may not reveal every visible assembly defect, particularly if the defect does not affect the functions exercised during the test.
The PCB Assembly Test Toolkit is intended for electrical functional test development. It is not an AOI image-processing system.
An explanation of AOI inspection methods and their role in PCB assembly quality control is available in PCBCool's technical guide.[5]
Licensing and source code
NI describes the PCB Assembly Test Toolkit as a license-free collection of measurement VIs and examples.
Source code is available through NI's public GitHub repository. The repository contains a license file, contribution guidelines, and installation documentation.
The license applicable to the source code should be checked in the repository before redistribution or modification.
Licensing of the toolkit should not be confused with licensing requirements for LabVIEW, TestStand, or other NI software used with it.