When relaxing in a hot tub or playing in the pool, we rarely think about the reliability we place on the controller. Turning up the water temperature in the winter or cooling it off in the summer comes with just a couple clicks of a button. We see a user-friendly LCD screen with a few temperature options, but the system inside is far more complex than it appears. When a company manufacturing pool and spa controllers approached Cyth wanting their new product line tested to assure controls for temperature, pumps and pre-set programs worked smoothly and consistently, Cyth knew they could provide the client with a better ATE system before their product hit the market.
The company produced three different controller varieties, an Main Control Panel (MCP), an Indoor Touch Panel (ITP) and a Wireless Remote (WR). The ITP and WR interfaced with the MCP, which acted as the master control panel, containing the physical I/O that controlled everything else. The client needed a bench-top test system complete with a small cabinet containing electronics underneath to test the circuitry of the controllers, and a camera looking from above to evaluate the display. This test system would assure their pool and spa controllers were of their high standard of quality before the products were put on the market.
Cyth began by testing the LCD screen quality as well as the communication to the controller, then completed I/O testing on all its functions with an automated run-through to assure communication with the ITP. After the screen quality check passed, the communication was tested: for the ITP it was RS232 and for the WR it was RS232 plus a transceiver. The MCP needed a vision and touch screen test for the LCD touch screen, and then systematically went through the relays, the button inputs and RTD temperature sensors. Once the communication tests were passed, the unit passes.
Cyth’s engineers utilized LabVIEW Vision Assistant while integrating the LabVIEW code with the Basler camera. The camera was run through a USB hub, but a way to detect if the controller was on (a software perimeter) was needed to know how to handle certain test case scenarios. So Cyth used an NI USB DAQ to determine the circuit’s power status for the controller to know whether power was being supplied. All the controllers communicated via RS45 so Cyth used a generic USB to RS45 device and wrote custom LabVIEW code to communicate with the controller.
A quality assurance specialist could now place the controller inside the test system that Cyth produced, allowing the tester to capture a photo of the LCD screen during its loading phase, as well as complete a touch screen test.
When creating the system, some discoveries were made regarding how the client’s controllers operated electrically; the physics of their circuitry was quite unique. Another issue was in-rush current on the ITP. The MCP would go into strange boot states because it took an AC voltage, rectified to a DC, and then divided down that voltage into very small processing chips. If you were to turn the controller on to run a test, then turn it off and try to start the second test, it would fail to properly shut down. It would require a hard reset instead of being able to adapt to the second test. This challenge gave Cyth the opportunity to collaborate directly with the client’s engineers to generate a solution.
Having automated test equipment rather than manually inputting values and testing the controllers saves labor costs, ultimately driving down the cost of the controller. Automation in the testing process also adds an extra level of quality assurance. The system will work the same way every time, providing the company with the comfort knowing that they are giving their customers a product that has been tested to work effectively each time. The client was thrilled to be able to offer their customers the best possible product thanks to Cyth’s consistency, reliability and precision.
• LabVIEW 2015 (32-bit)
• LabVIEW Vision Assistant
• 1920x1080 (2 MP) 25 fps, color USB 3.0 Basler Camera
• 16mm C Series Fixed Focal Length Edmund Optics Lens
• NI PXI-1042
• 2-Port, Isolated, RS485/RS422 PXI Serial Interface Module (PXI-8433/2)
• 3-Channel, 20 V, 1 A PXI Programmable Power Supply (PXI-4110)
• 100-Channel, 1 A, SPST PXI Relay Module (PXI-2569)
• 64-Channel, ±30 VDC, 32 Sink/Source Inputs, 32 Source Outputs, Bank-Isolated PXI Digital I/O Module (PXI-6514)