| With the widely use of Constant-Temperature Heating PTC, its productions increasesevery year, the quality becomes the major focus, and the test of product is a powerfulguarantee to PTC’s quality. As is known, there are many problems in product testing, suchas the standard are not unified, coarse measurement, the operation is complex, wasting ofhuman resources, etc. To solve these problem, intelligent instrument arises at the moment.In the production and application of Constant-Temperature Heating PTC, the mostimportant parameter are room temperature resistance, surface temperature, surge currentand the ability to withstand voltage. This article mainly focus on room temperatureresistance, surface temperature and surge current of PTC, to be a integrate system. Themeasurement of resistance and current adopt this method, first amplification the voltage ofsampling resistance, then transform to digital signal, finally get the value calculated byMCU. The measurement of temperature is difficult and important, it need to choose the bestof the three methods (infrared, thermocouple and film platinum resistance). The systemmake up by control unit, resistance and current measurement unit, keyboard and displayunit, temperature measurement unit, circuit unit and transformer unit. Measurement unitsresponsible for sampling the parameters of PTC, control unit processes data, settingparameter and display results need keyboard and display unit, the circuit and transformerunits have auxiliary function. The host communicate with slaves through RS-485, to controlthem and exchange data.Combining with the thought of integration, module and the principle of simple andpractical, then design a comprehensive test system. The system could measure the roomtemperature resistance, surge current and surface temperature automatic, meet the needs ofthe actual test. This system help manufacturers to improve the qualified rate, and clientcompany’s product inspection, reduce customer complaints and commercial disputes. |
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