Batch-manufactured PCBs must pass both in-circuit tests (ICT) and FCTs before leaving the factory. ICT is usually the first test step in which every electronic component is tested and every short and open fault of every circuit are checked online. Most PCBs use firmware to control the integrated circuit board.

After the ICT, we can judge the quality of electronic components and parts for the PCBs in question, but we cannot determine whether the whole circuit functions properly or not. Test engineers must build an analog circuit environment to conduct FCTs on test point (TP) on an integrated circuit board. The FCT simulates the functions of finished products and tests if those functions complete.

In most cases, FCT systems on the production line only test one type of PCB. Such systems are generally developed by designing the control boards and connecting all the I/O ports to the test fixture. Then test engineers build the firmware for the control board to set up the simulated operating ambient of the finished products to test voltage and current as well as the corresponding sequential control. After testing is complete and products leave the factory, the FCT system is often shelved, and FCT systems developed for different PCBs require additional engineering resources for plate making, programming, and wiring. In addition, more complex functions are constantly added to PCBs, which makes some functional testing more difficult to build.

Honeywell wanted to avoid duplicating effort that was often the result of this development process and identify a lower-cost, more flexible solution that could address FCTs of multiple PCB products and the growing complexity of PCB functionality.

Using the PXI hardware platform and LabVIEW software, Honeywell focused on creating a complete set of comprehensive automatic function testing to test audio, video, and various signals such as voltage, current, and digital.

Functionality Requirements

Honeywell prioritized the following test functions:

• Multiple high-speed bidirectional I/O that monitors the state of the fixture and realizes communication protocols such as I2C to implement the sequential control of most chips on the PCBs
• Multiple analog input and output channels that can generate waveform signals as the simulated inputs for the PCBs
• Multichannel programmable switch matrix for on-off control
• RS232, RS485 serial port card to realize serial communication
• Programmable multimeter for voltage and current measurement
• Oscillograph for frequency measurement and waveform acquisition
• Video generation, acquisition, and analysis
• Audio acquisition and analysis
• Programmable power module
• Unified programming environment

Using traditional instruments to achieve this level of functionality would require prohibitively high costs. Implementing the NI solution with PXI and LabVIEW helped us achieve our goals and cut costs by half.