便攜式信號采集在機器健康診斷系統中有較高的應用價值。機器健康診斷的信號特點是包括低頻信號。本文研究是為了實現簡易而且低成本的低頻便攜式信號采集。以Microchip公司單片機PIC18F1320為核心設計信號采集電路,實現了信號的采集和保存。系統采用串行電可擦除芯片24LC32A保存數據,經過有線通信,信號數據由串行口通過MAX232芯片輸送到微型計算機接收和保存,最后繪制出信號波形。 微型計算機程序采用Visual Basic編程。研究成功采樣頻率為3 kHz的復雜信號,證明該方案符合設計要求。
Abstract:
Portable signal acquisition is useful in machine health monitoring systems. The signal characteristics of machine health monitoring includes low frequency signals. The goal of this study is to realize simple, inexpensive and portable low frequency signal sampling. This paper provides the project of signal acquisition system design based on PIC18F1320 microcontroller manufactured by the Microchip Technology Incorporation to achieve signal sampling and storage. The system adopted EEPROM 24LC32A to store the signal data. The microcomputer received data via wired link with the MAX232 IC through the serial port. The microcomputer program, programmed in Visual Basic, received the data, stored it and plotted the signal. The study successfully samples 3kHz complicated signals and thus meets the design requirement.
為了提高傳統溫度控制系統的性能,將PID控制理論與嵌入式系統相結合,采用瑞薩電子公司的H8S/2166作為核心處理器,AD公司的AD7705以及熱敏電阻溫度傳感器作為溫度檢測單元,利用4×6小鍵盤、LCD顯示器和S1D13305液晶控制器達到良好的人機交互,設計出了一個應用于化工領域的嵌入式實時溫度控制系統。相比于傳統溫度控制系統,該系統提供了更強的計算能力和可擴展能力,采用增量PID控制算法實現復雜控制。通過實驗,該系統能達到0.1 ℃的溫度控制精度以及小于120 s的溫度穩定時間。
Abstract:
In order to improve the performance of conventional temperature control system, combining PID control theory with embedded systems, using the Renesas Electronics Corp. H8S/2166 micro-controller as a core processors, AD7705 and thermistor temperature sensor as a temperature detection unit and 4×6 small keyboard, LCD and S1D13305 LCD controller as a good human-computer interaction, this paper designed an embedded real-time temperature control system which is applied in chemical industry. Compared with conventional temperature control system, this system provides more computing power and extensibility, and adopts PID control algorithm for complex control. Through the experiment, the system can reach temperature control accuracy of 0.1 ℃ and temperature stabilization time of less than 120 seconds.