Computer Control System Module Design

Computer control system
The single-chip microcomputer ADCm842 and the computer constitute a PC computer control system, which controls the voltage rise and fall, A/D conversion, data processing and analysis during the test.
Module design
The withstand voltage test is based on the high-performance single-chip microcomputer ADCm842 as the core of the computer control system. The ADCm842 integrates 12-bit A/D and D/A converters, and has a DMA controller that can complete the high-speed conversion from A/D to RAM. The ADCm842 has a superior 8052 core, and its peak efficiency can execute 20 million instructions per second. The ADCm842 has 62KB of on-chip program flash memory; 4KB of on-chip data flash memory, and 2.3KB of on-chip data RAM that can be erased and written 100,000 times. The single-chip microcomputer of the test system uses C51 programming to control the test and process the data, and the PC computer mainly provides the interface for human-computer interaction. This test system is flexible and convenient to use.
The test control system includes control of voltage source, data collection, A/D conversion, data analysis, data output and display, data storage, etc. At the same time, the withstand voltage test system software can realize self-check before testing, automatically eliminate possible error factors and fault alarm functions. Accurate control of test voltage is achieved through software. When the test voltage reaches the test requirement value, the test is started. The software controls the voltage according to the test standard in IEC61010. The computer is programmed with VC++, and the test interface is intuitive and easy to operate. Users can set different test times and leakage current thresholds according to actual tests, monitor the test progress and display the test results. If the tested sample breaks down or other possible overcurrent phenomena occur during the test, the output voltage of the tester can quickly drop to zero and send out an alarm signal.
In the actual test, a 0.5-level ZX117A adjustable high-voltage resistor box is selected as the standard test piece. The output voltage is raised to the set value through the single-chip microcomputer control, and the voltage output is monitored by the CS1940 digital high-voltage meter of Nanjing Changsheng. The error of the output voltage does not exceed ±1.5%. The system leakage current was measured using Agilent's six-and-a-half-digit digital multimeter A-34401A. The calculated value of the leakage current was used as the standard to evaluate the test accuracy of the system. According to the latest international standard IEC61010, different high voltages were applied to the same resistor to perform leakage current tests. The test results showed that the repeatability of the measurement data was good, and the test error of the leakage current was ± (1.5% ± 0.05mA).
Measuring range of insulation withstand voltage tester Withstand voltage AC0～5kV/100mA Insulation DC250V 500V 1000V 1～9999MΩ Performance characteristics Insulation withstand voltage tester with improved performance Test voltage, time, leakage current, insulation resistance are all digitally displayed, accurate and beautiful Measure insulation resistance value up to 1010Ω Intelligent, single-chip computer control, test insulation resistance, voltage, leakage current, time can be adjusted arbitrarily, wide range, high accuracy Can test the resistance and voltage of the product, and can also screen qualified and unqualified products, sound and light alarm Technical parameters Output voltage AC 0～5kV ±3%, arbitrarily adjust breakdown current AC 0～100mA ±5%, arbitrarily set timing 1～99s, ±3%, manual insulation resistance test voltage DC 250V/500V/1000V, Measuring range 1～9999MΩ, ±3%～±5%, arbitrarily set transformer capacity 750VA Main functions: I/W, W/I automatic conversion, manual/automatic, single-chip microprocessor control test, pass/fail sound and light alarm, breakdown protection, etc.