|
Intelligent multimeter with a microprocessor or microcontroller high-end digital instrument, it is a hardware and software combination, the software decision instrument intelligent level of the novel instrument. Its main advantages are high accuracy, strong function, with automatic calibration, automatic measurement, automatic data processing functions, can be connected via RS-232 or IEEE-488 standard interface with the computer, automated testing and real-time control functions. Can be used in the field or laboratory, can also be used in embedded measurement and control system. The object of study of the subject for intelligent multimeter chip for FS9704, its internal core components of the high-resolution Σ-△ ADC, with other functional network to complete the measurement function. Meanwhile, FS9704 further comprising a microprocessor interface, can be connected through an interface bus and a microprocessor, the control FS9704 the operation. The FS9704 application system mainly consists of the following modules: measurement module, microcontroller module, memory module, display modules, communication modules, power modules. Mixed-signal microcontroller C8051F020 as control components, control measurement module, the storage module to read and write, display module to communicate with the host computer functions. This paper carried out the following research: on the one hand, the basic components of smart multimeter and generally works as an entry point to study the internal structure of the FS9704 chip analysis works. First, the analysis of the structure and working principle of the FS9704 internal analog-to-digital converter, to discuss its transmission characteristics of the analog-to-digital converter output equivalent voltage conversion algorithm. Then FS9704 internal function network function decoder, multiplexer and pre-filter op amps and comparators works, focuses on the the millivolt file under FS9704 function network diagram. Next, introduces the FS9704 the microprocessor interface, its internal control registers read method, and its interrupt mechanism and the measurement register function. Finally, the analysis of the FS9704 power system works. On the other hand, the main ideas and methods of the smart the multimeter chips application system design. First of all, on the application of the system function module division, divided into the measurement module, microcontroller module, storage module, five parts of the display module, communication module and power module. Then, the design and implementation of each module, focusing on core technology issues were discussed. Measurement module mainly to complete the conditioning and analog-to-digital conversion of the signal being measured, the whole process is done under control of the microprocessor. The microprocessor via the control interface, in accordance with certain timing control right FS9704 control. The control process required some configuration information can be read from the external FLASH memory through the SPI interface, required to record the data can also be written to the memory. The measuring results obtained can drive the liquid crystal display module for display. In addition, the use of the communication module, the host computer can be easily and SCM communications, monitoring the measurement process, store, display measurement data. Various functional modules of integrated hardware and software design, to improve the system functions, system and perfect after a comprehensive test results show that the application system can achieve the DC millivolt measurement, measurement accuracy reached the requirements of the relevant national standards.
|