The Study And Development Of Screw Type Water Chiller Controller Based ARM

With development of society and improvement of people's life quality, Central Air-conditioner have been developed fast and applied in large buildings, factories and schools.Screw Type Water Chiller was one of Central Air-conditioners, and the most widely used because of immense advantages over other Chillers.Now a syestem of PLC with a touch-screen interface was used in the Screw Type Water Chiller, easy to develop, but with high cost. With the High-cost-performance advantage of the ARM processor, it was used in some field. This article aims to develop a set of ARM-based Screw Type Water Chiller Controller. It can get a real-time data acquisition and data processing, and could communicate real-time data with up PC, and it has multi-bus interface, easy to get remote control and networking.On the basis of the analysis on Screw Type Water Chiller's working principle, it declared the control need and determined the control strategy and overall design of the controller. The control system was divided into two parts: the unit controller and HMI module MD304L, eView protocol was used in communications by RS485. CAN fieldbus was adopt in Local network, at a rate of 250Kb/s with 250m maximum distance, LonWorks fieldbus or traditional RS485 bus was used in Larger network.STM32F103ZET6 was the core processor of the screw-type water chiller controller. In the hardware system, designed power module, analog input and output module, 4~20 mA input and output module, multi-switch input and output modules, communication modules and so on.It elaborated the software design on the screw-type water chiller, including system design; power-generating units initialization settings; self-test process; switched process; level adjustment process; the normal shutdown process; analog acquisition module based-SPI; communications module(CAN and I2C); and the communication based-eView with MD304L module; MD304L interface development.All of the module's hardware and software debugging are completed and finally it tested the whole screw Type Water Chiller system, which indicated that the controller can work stably and with high-precision measurement, which satisfied the design requirements. The controller can be used in central air-conditioning screw-type water chiller and other products.