Design And Implementation Of Electrical Water Heater Automatic Test System

In recent years, the water heater is one of the fastest yield-growing household electrical appliances whose quality is related to all users'vital interests. Any water heater must undergo strict testing of electrical safety, energy conservation and aging, etc., in order to ensure that its parameters and indicators are in line with relevant international and domestic standards. If using traditional artificial test or partially automatic test, it will not only result in heavy workload, long cycle, low efficiency, but also affect the measurement accuracy because of the introduction of man-made factors.At present domestic water heater market has tremendous potential, strong demand, and fierce competition, but many water heater manufacturers have not established accordingly Automatic Test System (ATS). ATS can complete product test according to relevant standards under circumstance of less manual intervention. The test process has pretty high automation and accuracy. ATS can greatly reduce the manual labor intensity, minimize human error and ensure the fairness and correctness of the test results.First, this paper briefly introduces three main types of domestic water heaters and compares their advantages and disadvantages, summarizes the development, status and composition of ATS. Then according to user requirements and national standards, the paper builds the test scheme and system structure of Electrical Storage Water Heaters (ESWH) ATS, implements environment control and data acquisition by choosing corresponding industrial test instruments, designs and realizes the ESWH ATS based on the Testing Software Development Platform of Household Appliances(TSDP-HA).The ESWH ATS is based on the current status of water heaters'parameter-testing, adopts RS-485, GPIB communication interface standards and FX series PLC's No Protocol Communication, realizes the automatic testing and comprehensive management of various ESWHs'parameters in accordance with national standards, further ensures the"zero-defect production", and has huge economical and practical value.The paper designs and realizes the ESWH ATS's modules of environment control, data acquisition, transport and communication, and performance testing in detail. The environment control module uses FX series PLC's No Protocol Communication. The data acquisition, transport and communication modules mainly consider two communication interface standards, i.e. RS-485 and GPIB, compare their performance and application conditions by analyzing their communication principle and technology according to their industrial properties as well as the programming technology of computer data communication. The performance testing module can be divided into several sub-modules and be realized separately, the testing method of which can also be extended to other types of water heaters such as solar plus electrical water heaters and other new energy-conservation or safety technologies. In order to improve the handling capacity of the testing system, recover data after machine collapse and query historical data, database programming is also needed.Error is inevitable for an ATS. This paper analyzes the errors of ATS, identifies the reasons of various errors, and points out corresponding amendments and process method of three types of errors, in order to enhance the accuracy and validity of testing data. After that, the paper does some preliminary research on the possibility and relevant technical problems of upgrading the TSDP-HA to Networked Testing & Control System (NTCS) based on C/S & B/S mesh mode. Lastly, the paper summarizes the research and implementation of ESWH ATS, and looks to the future of new generation ATS and NTCS.