The PH Controller Base On The USB Communication

Clarification neutralize is the key processes in the sugar production. The control of pH-value and temperature on cane juice directly affects the recovery, product quality and private benefits of sugar. It limits increase of the economic benefit of sugar mill, because of the pool production environment and lots of sediment incrustation of production process. Automatic control of pH-value has not been solved appropriately.As a new generic serial buses standard, the application of USB is more and more widely used. The USB has the characters—strong error correcting capability, fast speed, little system resources, convenience and agility, and so on. This thesis introduces a kind of sugar pH-value controller based on USB communication. The controller uses the microprocessor AT91M55800 as the core and makes the most use of AD-DA resource of AT91M55800. The microprocessor of USB communication is PDIUSBD12. It use USB communication to implement pH-value data gathering and controlling.In hardware, the main board and pH-value signal conditioning board are designed. The main board circuit includes AT91M55800 microprocessor circuit, storage circuit, USB communication interface circuit, RS232 interface circuit, AD interface circuit and DA interface circuit and so on. The pH-value signal conditioning board mainly changes the small voltage of glass electrode pH-value to a 0-3V signal.In software, USB communication protocol is analyzed, and USB firmware program of main board is written. Using WDM drive development tool DriverStudio implements USB driver, it makes PC and pH controller realizing data transfer quickly and effectively. Meanwhile, LabVIEW is used to develop pH-value monitoring software, I realize the control of liquid level through USB mode.The experimental result indicates that the sugar pH-value controller based on USB communication in this paper is convenient, nimble, flexible and so on. The VI technology can achieve the resource sharing of hardware and software. The software of VI can realize signal sampling and waveform display, it also can store, playback and share the waveform data collected. This controller is not only suit for pH-value control, but also can be applied to other Tracking and Controlling field.