Application Areas: Product Testing Challenges: Using DIO to control a resistor array, GPIB to control the collaborative operation of various instruments, and an oscilloscope card to monitor the waveform of the electronic ballast signal in real time. Products Used: LabVIEW 6.0 Application Builder, SQL database plugin, NI-DAQ 6070E, NI-DIO-24, NI-Scope 5112, NI-GPIB card, Advantech industrial PC. [align=center]Physical image of the industrial PC chassis[/align] Application Solution: Primarily based on Windows 2000 environment, the test software is written using LabVIEW 6.0. The GPIB card controls the power supply and measuring instruments, the NI-DIO-24 controls the large-scale resistor matrix, switches combined loads, and NI-DAQ and NI-SCOPE are used to collect various voltage, frequency, waveform, and other parameters. Database technology is also used for data recording, mean analysis, CPK analysis, batch difference analysis, defect statistics, and other industrial index calculations. Introduction: Ballasts are part of lighting systems. They are categorized by load capacity, including single-filament, double-filament, and triple-filament ballasts, and can be driven by 120/277V power frequency. The main tests include their operating power, current, efficiency, harmonic distortion coefficient, and the frequency and voltage of each filament. Other tests include their starting voltage, frequency, and no-load characteristics. [align=center]System Hardware Structure Diagram[/align] [b]Test System Hardware Structure and Introduction A: Industrial PC Configuration[/b] The industrial PC mainly uses a Pentium 4 motherboard with integrated graphics and network card, a baseboard with ISA and PCI slots, a pull-out keyboard and mouse, floppy drive, optical drive, and a USB interface (for easy database updates and test data reading); B: NI-GPIB Card It is based on the IEEE-488.2 communication protocol, uses an ISA slot, and features plugin and play functionality. It is mainly used for communication with instruments. This system utilizes two instruments: an Agilent 6812A power supply and a Xitron 2503 power analyzer. The former supplies power to the electronic ballast and can be controlled via a GPIB card to adjust the supply voltage, frequency, and define voltage waveforms. It also features automatic shutdown protection against overload. The latter detects power and current, converting the current into a voltage signal at a ratio of one-tenth using a current transformer. This signal is then combined with the voltage to analyze parameters such as power, harmonic distortion coefficient, and power factor. [align=center]Test Program Main Panel[/align] C: NI DAQ-6070E This card has 16 input channels. This system uses differential input, with channels choch8, ch1, ch9, ch2, ch10…..ch7, ch15 combined in pairs to form eight input channels. The voltage range is set to -10V to 10V. However, the voltage of the test object often does not fall within this range. We use a self-made voltage adjustment module to solve this problem, available in several specifications such as 1/1000, 1/100, 1/20, 1/10, 1/5, and 10/1, with gain adjustable via digital DIP switches. Additionally, the test board itself can sometimes affect the test signal. To eliminate this influence, and given that the test object is an AC signal, this system also uses a 1:1 transformer for isolation. What we read using the DAQ is actually a set of waveforms; we need to analyze the waveform array to obtain its frequency, RMS value, and waveform distortion coefficient. [align=center]Parameter Acquisition Program Snippet[/align] The system also utilizes two Counter/time channels of the DAQ. Counter0 generates a 50kHz square wave with a 50% duty cycle, and Counter1 generates a 120Hz square wave. The program defines their duty cycles as adjustable between 10% and 90%. To improve the load-carrying capacity of the 120Hz signal, it needs to be amplified using a transistor. These two square wave signals are connected to the ballast's control port (as shown in the diagram) to jointly regulate its operating state. D: Resistor matrix and switch matrix controlled by DIO-24 The system uses 24 TTL level signals from the DIO to control the operation of each relay (normally open and normally closed). 1: The resistor matrix is ​​implemented by selecting a series of resistors according to the binary value relationship of 1, 2, 4, 8, 16, connecting each to a relay in parallel, and then connecting them in series. In this way, the system can obtain any resistance value by controlling the switching of these relays through the DIO. A general-purpose controllable rheostat box is thus formed. 2: The switching matrix needs to switch between full load, overload, no load, power-off, and power-on states during ballast testing. The system uses a series of switches to accomplish this function. The developers made it an independent module. E: NI-SCOPE monitors instantaneous electrical characteristics . Some indicators in ballast testing are highly dependent on waveform characteristics, such as transient response and convergence. Oscilloscopes were previously used, but many weaknesses were found: they were space-consuming and expensive. Later, an oscilloscope card was considered, which can be directly plugged into the industrial PC's PCI slot, thus saving valuable space on the ATE (Automatic Equipment). The system uses the 5112 oscilloscope card to simultaneously detect the waveforms of the load voltage and filament voltage, displaying them on the test panel and recording them as test data. Like data acquisition cards, oscilloscope cards also have an isolation issue. Software Development and Performance Evaluation The system is programmed based on LabVIEW 6.0. Application Builder, SQL, NI-scope, and other plugins were also installed. We used two instruments with GPIB interfaces, and the developers used a rheostat box driver and a switching matrix driver. [align=center] ATE Production Line Site A: Modularization The developers created instrument drivers as needed, including the aforementioned rheostat driver and switch matrix driver. These modules, along with the original DAQ module, were integrated into a general-purpose module for acquiring various parameters. B: SQL Application A database was created using Microsoft Access, including three sub-databases: product specifications, typical sample values, and calibration errors. A series of product parameters can be input. When the main test panel is opened, the product model is selected, and the SQL module retrieves the corresponding model's parameters for use. C: Calibration Design Each test software must have a calibration function. Before mass production testing, the calibration interface needs to be accessed, and calibration is performed using a standard sample. More accurately, this involves calculating the deviation. First, the standard sample's value is tested, then compared with the sample's calibrated value, generating a deviation, which is stored in the calibration error sub-database. When entering the mass production test panel, the deviation is added to the measured value to obtain an accurate measurement. D: Software Reliability and Speed Reliability: When testing the reliability of the software, we randomly selected 100 products and had five workers test each. We then analyzed the results, calculated the average, and compared it with the highest and lowest values. If the difference did not exceed 3%, the system was considered reliable and suitable for mass product testing. Speed: The system utilizes various circuit boards, demonstrating a significant speed advantage compared to conventional instrument testing systems. Conclusion After adopting LabVIEW software, engineers have significantly accelerated the development cycle of the testing system. The software also boasts excellent readability. The use of numerous relatively inexpensive test boards has reduced company costs. I believe that with the further development of integrated circuits and the continuous improvement of the performance of various circuit boards, this advantage will become even more pronounced.