全自动冷饮机控制器外文资料翻译(3)

参考文献

[1] M. Langsdorf, M. Rall, D. Schuchmann, and P. Rinehart,―Temperature control of a microscope slide dryer,‖ in 1997 National Conference on Undergraduate Research, (Austin, TX), April 1997. Poster presentation.

[2] Motorola, Inc., Phoenix, AZ,Temperature Measurement and Display Using the MC68HC05B4 and the MC14489,1990. Motorola Semiconductor Application Note AN431.

[3] Motorola, Inc., Phoenix, AZ, HC05 MCU LED Drive Techniques Using the MC68HC705J1A, 1995. Motorola Semiconductor Application Note AN1238.

[4] Motorola, Inc., Phoenix, AZ,HC05 MCU Keypad Decoding Techniques Using the MC68HC705J1A, 1995. Motorola Semiconductor Application Note AN1239.

[5] Motorola, Inc., Phoenix, AZ, RAPID Integrated Development Environment User’s Manual, 1993. (RAPID was developed by P & E Microcomputer Systems, Inc.).

附件2：外文原文（复印件）

Temperature Control Using a Microcontroller:

An Interdisciplinary Undergraduate Engineering Design

Project

James S. McDonald

Department of Engineering Science

Trinity University San Antonio, TX 78212

Abstract

This paper describes an interdisciplinary design project which was done under the author’s supervision by a group of four senior students in the Department of Engineering Science at Trinity University. The objective of the project was to develop a temperature control system for an air-filled chamber. The system was to allow entry of a desired chamber temperature in a prescribed range and to exhibit overshoot and steady-state temperature error of less than 1 degree Kelvin in the actual chamber temperature step response. The details of the design developed by this group of students, based on a Motorola MC68HC05 family microcontroller, are described. The pedagogical value of the problem is also discussed through a description of some of the key steps in the design process. It is shown that the solution requires broad knowledge drawn from several engineering disciplines including electrical, mechanical, and control systems engineering

1 Introduction

The design project which is the subject of this paper originated from a real-world application. A prototype of a microscope slide dryer had been developed around an OmegaTM model CN-390 temperature controller, and the objective was to develop a custom temperature control system to replace the Omega system. The motivation was that a custom controller targeted specifically for the application should be able to achieve the same functionality at a much lower cost, as the Omega system is unnecessarily versatile and equipped to handle a wide variety of applications.

The mechanical layout of the slide dryer prototype is shown in Figure 1. The main element of the dryer is a large, insulated, air-filled chamber in which microscope slides, each with a tissue sample encased in paraffin, can be set on caddies. In order that the paraffin maintain the proper consistency, the temperature in the slide chamber must be maintained at a desired (constant) temperature. A second chamber (the electronics enclosure) houses a resistive heater and the temperature controller, and a fan mounted on the end of the dryer blows air across the heater, carrying heat into the slide chamber.

This design project was carried out during academic year 1996–97 by four students under the author’s supervision as a Senior Design project in the Department

of Engineering Science at Trinity University. The purpose of this paper is to describe the problem and the students’ solution in some detail, and to discuss some of the pedagogical opportunities offered by an interdisciplinary design project of this type. The students’ own report was presented at the 1997 National Conference on Undergraduate Research [1].

Section 2 gives a more detailed statement of the problem, including performance specifications, and Section 3 describes the students’ design. Section 4 makes up the bulk of the paper, and discusses in some detail several aspects of the design process which offer unique pedagogical opportunities. Finally, Section 5 offers some conclusions.

2 Problem Statement

The basic idea of the project is to replace the relevant parts of the functionality of an Omega CN-390 temperature controller using a custom-designed system. The application dictates that temperature settings are usually kept constant for long periods of time, but it’s nonetheless important that step changes be tracked in a ―reasonable‖ manner. Thus the main requirements boil down to ● allowing a chamber temperature set-point to be entered, ● displaying both set-point and actual temperatures

●tracking step changes in set-point temperature with acceptable rise time, steady-state error, and overshoot.

Table 1 gives a more precise statement of specifications.

Although not explicitly a part of the specifications in Table 1, it was clear that the customer desired digital displays of set-point and actual temperatures, and that set-point temperature entry should be digital as well (as opposed to, say, through a potentiometer setting).

3 System Design

The requirements for digital temperature displays and set point entry alone are enough to dictate that a microcontroller based design is likely the most appropriate. Figure 2 shows a block diagram of the students’ design.

The microcontroller, a Motorola MC68HC705B16 (6805 for short), is the heart of the system. It accepts inputs from a simple four-key keypad which allow specification of the set-point temperature, and it displays both set-point and measured chamber temperatures using two-digit seven-segment LED displays controlled by a display driver. All these inputs and outputs are accommodated by parallel ports on …… 此处隐藏：6583字，全部文档内容请下载后查看。喜欢就下载吧 ……