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Industry Information
Three types of controls used in ultrasonic flowmeters
2011-12-30 10:49:58

采用DSP控制数字信号处理器{DSP}是近年来迅速崛起的新一代可编程处理器。 1. The ultrasonic flowmeter adopts DSP to control the digital signal processor {DSP}, which is a new-generation programmable processor that has risen rapidly in recent years. Integrated baud rate ultrasonic generator and FiFO buffer, providing high-speed synchronous serial port and standard asynchronous

Serial port, and some chips also integrate sample / hold and A / D conversion circuits, and provide PWM signal output. Compared with single-chip microcomputers, DSPs have faster CPUs. Higher integration and larger capacity memory. DSP is a reduced instruction system

For a computer (Risc), most instructions can be completed in one cycle and multiple instructions can be completed in one instruction cycle through parallel processing technology. At the same time, the DSP uses an improved Harvard structure with independent program and data space, allowing simultaneous

Store programs and data. Built-in high-speed hardware multiplier adds multi-stage pipeline. Make it have high-speed data computing ability. The single-chip microcomputer is a complex instruction system computer (CiSC), and most instructions take 2-3 instruction cycles to complete.

With the Neumann structure, programs and data are stored in the same space, and only instructions or data can be accessed separately at the same time. The ALU of a single-chip microcomputer can only perform addition, and multiplication needs to be implemented by software, so it takes more instruction cycles and speed ratio

Slower. Compared with 16-bit microcontrollers. DSP executes a single instruction 8-10 times faster, and a multiplication operation 16-16 times faster. In the sonotrode. DSP can complete all functions except power conversion, such as main circuit control, system implementation

Japan-Ten monitoring and protection Although DSP has many advantages, it also has some limitations, such as the selection of sampling frequency, PWM signal frequency and its accuracy, sampling delay, operation time and accuracy. These factors will affect the ultrasound flow more or less

Control performance of the meter circuit.


采用AVR高档单片机控制单片机是一种在一块芯片上集成了CPU.RAM/ ROM、定时器/计数器和I/O接口等单元的微控制芯片, 具有速度快,功能强、 2. The ultrasonic flow meter adopts AVR high-end single-chip microcomputer control. The single-chip microcomputer is a micro-control chip that integrates CPU, RAM / ROM, timer / counter and I / O interface on a chip. It has fast speed, strong function,

High efficiency, small size, reliable performance, strong anti-interference ability, etc., are widely used in various control systems. The CPU of the single-chip microcomputer has undergone a development process from 4, 8, 16, 32 to 64 bits. In the sonotrode, monolithic

The machine is mainly used for data acquisition and calculation processing, voltage and current adjustment, PWM signal generation, system status monitoring and fault self-diagnosis, etc. It generally runs as the main control chip of the entire circuit and completes a variety of comprehensive functions. With D / A turn

The converter and MOSFET power module implement pulse width modulation. In addition, the single-chip microcomputer also has over current and over heat. Interrupt protection and monitoring functions for undervoltage conditions. Single-chip microcomputer control overcomes the inherent defects of analog circuits.

The control method obtains high-precision and high-stability control characteristics, and can realize flexible and diverse control functions.


采用FPGA控制现场可编程门阵列(FPGA)属于可重构器件,其内部逻辑功能可以根据需要任意设定,具有集成度高、处理速度快。 3. The ultrasonic flowmeter uses FPGA to control the field programmable gate array (FPGA), which is a reconfigurable device. Its internal logic function can be arbitrarily set according to needs, with high integration and fast processing speed. High efficiency. Its structure

It is mainly divided into three parts: programmable logic block, programmable I / O module, and programmable internal wiring. Due to the very high degree of integration of FPGAs, an FPGA can range from a few thousand equivalent gates to as many as tens of thousands or hundreds of thousands of equivalent gates. So an FPGA is

Can achieve very complex logic. Replace multiple circuits with integrated circuits and discrete components. It uses the hardware description language (VHDL) to design the system, and uses three levels of hardware descriptions (behavior description, PJL description, and gate-level description).

And the design style from top to bottom (starting from the description of the system function), three levels of description can be mixed and simulated, so that digital circuit design can be conveniently carried out, which has considerable advantages in reliability, size and cost. In other words, DSP

It is suitable for occasions with low sampling rate and high software complexity. When the system sampling rate is high (MHz level), the data rate is high (more than 20MB / s), the condition operation is small, and the task is relatively fixed, FPGA has more advantages.