Lecturer lecturer

abstract

With the rapid development of urban construction and the continuous expansion of heating network, central heating system has become a key factor in China's modernization. How to improve the economic and social benefits of heating network has become an urgent problem for heating enterprises and an important topic for heating and control in China. In view of the present situation of heating charge in residential quarters and the single-tube series heating system widely used at present, this paper puts forward an economical, reliable and intelligent scheme.

In this paper, an application system based on single chip microcomputer control is designed, which is used to measure the parameters of heating system, such as temperature and flow rate, collect heat consumption and billing data, and monitor and control the state of heating system. The intelligent heat meter realizes the measurement of flow, temperature and heat in the heating system. It mainly includes analog acquisition module, control module, communication interface module and display module. This paper expounds the hardware and software design of the whole system in detail.

Keywords: single chip microcomputer; Heat meter; IC card; supply heat

I. Introduction

For a long time, hot water heating in China has been carried out by district collective heating, with heating area as the settlement basis, regardless of whether users use heat. This settlement method belongs to the "package fee system", which seriously affects the enthusiasm of the heating party, and on the other hand, some users lack energy-saving awareness, resulting in a waste of resources. As the basis and means for heating companies to charge each user, heat meter is not only widely accepted by users, but also strengthens users' awareness of energy saving because the heat consumption is directly related to the cost.

Second, the system design scheme and its control principle

1. Workflow and design scheme

(1) workflow overview

The main program of the system detects whether the IC card is inserted, and if so, stores the data in the IC card into the single chip microcomputer. When the residual heat is zero, the system automatically closes all the room valves until the user buys the heat again and counts the heat into the single chip microcomputer. Under normal working conditions, the temperature values of five rooms are displayed in turn, and each room is displayed for five seconds. The system collects field data every 10 second to calculate heat consumption, adjust valve size and control room temperature.

This heat meter provides man-machine interaction function, users can independently query the temperature of each room by pressing the key, and can set the temperature value of each room.

(2) System design scheme

The hardware part of distributed management control heat meter is mainly divided into: signal transmission, AD conversion, IC card reading and writing, LED display, keyboard, power-off protection circuit and reset circuit. As shown in figure 1.

The temperature and flow transmitter converts the temperature and flow values into 4-20mA analog signals, which are transmitted to the AD converter and converted into digital signals that can be recognized by the single chip microcomputer, so as to calculate the heating value. The regulating valve receives the 4-20mA analog signal converted by DA, and changes the opening to control the room temperature. Digital tube can display room number, temperature and other information.

Figure 1 system block diagram

2. programming; arrange

Fig. 2 program flow chart

The main program detects whether the IC card is inserted. If so, it reads the IC heat into the single chip microcomputer to judge whether the residual heat is zero. If so, it closes all regulating valves and stops heating. The digital tube switches periodically to display the room number and temperature of each room. The system collects the field analog quantity every 10 second, and calculates the heat consumption of this 10 second. After collecting the room temperature, the valve adjustment subroutine compares the actual temperature with the set temperature, and appropriately adjusts the valve opening. The key interrupt subroutine provides users with functions such as temperature query, temperature setting, remaining and used heat query.

Third, the research conclusion of this topic.

According to the characteristics of central heating in actual residential areas, this design designs a set of practical heat meters based on single chip microcomputer, which realizes real-time temperature and flow collection, room temperature can be set, and provides man-machine interaction function, which is simple and convenient to use.

The system has the following advantages:

(1) When no one is at home during the day, you can turn off the heating or turn it down to save energy and prevent waste.

(2) Selective heating can be provided, and multiple rooms are set separately, so that idle rooms do not waste heating.

(3) the implementation of IC card charging method, how much to use, how much to buy, different families treat differently.

(4) The system has low cost and simple operation.