Headless ATE system increases production reliability and efficiency

-September 17, 2012

Many manufacturers use manual test equipment that comprises stand-alone COTS (commercial off-the-shelf) test instruments, such as digital multimeters, oscilloscopes, and hipot testers. COTS test instruments often require configuration and programming using their front panels. The required sequences of button presses to program these instruments through multiple selection menus can be cumbersome and prone to errors, and can subject the test process to test inconsistency. Quality-control processes are driving manufacturers to automate test equipment in order to ensure consistent configuration control and data collection.

PC-based ATE (automatic test equipment) systems provide control of the testing process, manage instrument configurations, increase test throughput, and address the issues associated with manual test. Although PC-based ATE is widely accepted, many manufacturers still test manually, for a number of reasons.

The PC-based ATE systems deploy a PC with each test system, which requires a minimum level of operator skill and IT maintenance. For benchtop systems, the keyboard, monitor, and mouse occupy precious space on the production floor. Operator skill levels and language barriers may necessitate significant training for some manufacturers. In particular, setup and configuration during product changeover can be challenging. Also, the accessibility of Web browsing and other PC software can distract operators using PC-based ATE. Responsibility for IT administration of PCs on the production floor is a gray area at some organizations.

Such issues can lead to operator error, inefficiency, and inconsistency in the testing process. To avoid those problems, a simple, headless ATE system may be all you need in a facility with multiple manual test stations; operator usability concerns; or a low-volume, high-changeover product mix.

Headless ATE system

Engineers at Bloomy Controls developed a headless ATE system that is simple to operate and doesn’t require PCs on the production floor. The system is headless because it doesn’t need a keyboard, monitor, touchscreen, or mouse; instead, it contains a physical interface comprising a few mechanical buttons, LEDs, and an optional bar-code scanner. A supervisory application, located on any PC connected to the manufacturer’s LAN (local-area network), can monitor and manage multiple headless ATE systems. The supervisory application lets managers control configurations sent to each headless ATE system and track the efficiency of each station, production line, and operator.

Bloomy Controls’ headless ATE system uses a 3U (three-unit) rack-mount cabinet with a 1U shelf that contains a National Instruments Single-Board RIO (reconfigurable I/O) implementation running LabVIEW, a power supply, and an operating panel. In addition to the 1U shelf, the cabinet contains the requisite COTS test instruments for each test system.

Figure 1 shows the system, which in this application uses an ac power source. Most COTS test instruments come in 1U and 2U forms that will fit into a 3U enclosure. The headless ATE system in Figure 1 contains a 2U COTS programmable ac power supply. A system clock time-stamps test activities that a supervisory application can record.

The headless system provides only the most basic operator controls, implemented by manipulating large mechanical buttons on the front panel, which can be configured and modified to meet the needs of the test process. In the headless ATE system in Figure 1, the LED-illuminated buttons are clearly labeled, in order, Test, Stop, and Retest. Green and red LED panel indicators, labeled Pass and Fail, inform the operator of the test result. The front-panel buttons and an optional bar-code reader are the only operator interface; consequently, the headless ATE system requires minimal operator training and eliminates the PC and associated maintenance.

The buttons and LEDs are monitored and controlled via a digital-I/O port in the NI Single-Board RIO (Figure 2), which contains a real-time processor, an FPGA, and analog and digital I/O. The board provides integrated communications via such protocols as Ethernet, USB, CAN, and RS-232 to control the COTS instruments, communicate to the UUT (unit under test), and connect to the supervisory PC.

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