Design Of The Ultrasonic Commitiva Heat Meter

Heat meter is an instrument which can measure, calculate and display the caloric value that is released and absorbed by the heat-exchange system; it is a Mechanical&Electrical integration instrument which used high accuracy sensor and microprocessor as the main parts, and it also plays the crucial role in the process of heating system reform of China. With the developing reform of the heating system, It also exposed some deficiencies, such as poor accurate, huge power consumption, easy attaint and hard to install because of using lineate communication technologies as the mode of automatic meter reading systems.On this basis, this paper designs a new type of heat meters for users, which apply to the heating supply system reform and user expectations currently. Its characteristic is as follow:(1) Accurate measure. This paper uses the theory of the ultrasonic time difference to calculate the flow value, and use the theory of enthalpy difference to calculate the caloric value. As ensuring the accuracy of the calculating, it uses the TDC-GP2which is made by German ACAM Company as the flow and temperature acquisition equipment.(2) Low-Power Design. This paper uses the MSP430F449which is made by the TI Company as the core processor, its marked characteristic is low power consumption, together with the TDC-GP2and wireless automatic reading system which is supported by ZigBee technology made the total system work for six years in using only lithium battery.(3) Running reliable, hard to damage, easy to install and maintain. Ultrasonic sensor is the non-contact measuring; its measurement process is unacted by impurity, chemical substances, and magnetic materials. It can install horizontal or vertical by low pressure loss. These characteristics made its running process are unacted on external environment, hard to damage, and using long time.(4) Wireless automatic reading system. Wire automatic reading system has its own advantages, but it must consider the specific method into the initial period of the building design. It go against transforming of the current heating supply installation, and wiring hard, huge power consumption, using lithium battery unreliable. The wireless reading system which is supported by ZigBee technology can overcome the disadvantage above.