Abstract: This article proposed one kind uses the AVR monolithic integrated circuit to take master control central the ozone therapy meter design proposal, and has given the system overall concept, the software and hardware design structure and the antijamming measure.
Key word: AVR monolithic integrated circuit; Medical ozone therapy meter; Software and hardware design
Outline
The ozone takes one highly effective cold sterilization method, at present widely was already applied in the various trades and occupations. Has highly effective, the rapid sterilization ozone before the hospital environment disinfection, the technique aspects and so on disinfection to apply widely, its treatment result surpasses other traditional sterilization treatment meter. Therefore develops one kind of movement to be stable, the easy to operate, the portable ozone therapy meter product, provides one kind of convenience for the gynecology department illness sickness patient effectively to treat the way in the home, has the practical significance.
At present in the market condition same type product is uses the 80C51 monolithic integrated circuit for the control core, although can also realize its demand function, but carries out the speed to be slow, in long lasting work environment, specially in ozone therapy meter’s internal high efficiency air pump module and under ozonizer disturbance, system power loss high and anti-jamming energy balance, the system performance unstable and so on questions then in relief come out. Regarding this article has used ATMEL a Corporation’s section of AVR upscale monolithic integrated circuit, has made the improvement to the control system, enhanced the complete machine performance.
The ozone produces principle and method
The ozone produces the way has many kinds, at present in the industry the ozone production mainly uses the corona discharge law, basic principle as shown in Figure 1.
Figure 1 ozonizer basic principle
In the ozonizer, between a pair of electrode (usually uses glass) by the dielectric body and the air gap (usual oxygen-containing gas) separates. When in addition AC high voltage, along with voltage value’s elevation, in the air gap has the corona discharge, the gas is ionized, in gap oxygen ion concentration sharp growth, under the greatly strengthened big electric field action of force, the gas molecular collision acceleration, the oxygen ion and the oxygen member as well as the oxygen ion has the response production ozone.
Different may divide into according to the electric power supply frequency: Power frequency ozonizer, intermediate frequency ozonizer and high frequency ozonizer.
System gross structure design
The medical ozone therapy meter system take the ATmega8L-8PI high performance microprocessor as a core, mainly by the power source module, the ozonizer, the air pump module, the serial port communication, the LED display circuit and the keyboard and so on is composed, as shown in Figure 2. The monolithic integrated circuit through the relay output control ozone module and the air pump module’s work, simultaneously the monolithic integrated circuit also controls operations and so on LED demonstration and keyboard entry.
Figure 2 control system overall diagram
ATmega8L-8PI microprocessor
ATmega8L-8PI is one section uses the low power loss CMOS craft production based on AVR RISC (simplification set of instructions) the structure high performance, the low power loss 8 monolithic integrated circuits. The processor has on electricity replacement delay circuit which may control and programmable owes the voltage examination electric circuit, the interior and exterior the altogether 18 interrupt sources, 5 kind of dormancy patterns. 32 working registers and the rich set of instructions connect when together, causes the majority of instructions the execution is only a clock cycle. Therefore, ATmega8 may achieve nearly 1 MIPS/MHz performance, the running rate will be higher than 10 times compared to the ordinary monolithic integrated circuit.
It internal integrated the 8KB Flash program memory, 512 B EEPROM, to support ISP and the IAP programming, the programmable procedure adds the mil, 3 PWM channel, 8 group 10 ADC, 2 belt pre-frequency division 8 fixed time/counters, 1 belt pre-frequency division 16 fixed time/counters, the RC oscillator’s programmable watch-dog timers and so on; As well as I2C, SPI, the UART connection, may receive from the superior machine RS-232 connection downloading procedure, only needs the external connection crystal oscillator, the datum power source and so on minority several components then to carry on the work, facilitates system’s development and the development enormously.
Ozonizer module
Treats meter’s safety performance aspect request according to GB code GB9706.1-1995 and the GB4343.2-1999 stipulation’s home use medical service, we select the ozonizer module mains input is AC220V/50Hz, the power is 13W, the air output is 100~200mg/h. According to the choice different function pressed key, the ozone concentration is adjustable, by functional control procedure interior automatic control. Treats the meter to altogether have four functions: The air sterilization, the ozone water treatment, the vaginitis treatment as well as the cervicitis treat. When first two kind of functions, the gas flow amount is the normal flow ≥1.5L/min. When technical permission, the current capacity may increase to 2L/min, the ozone concentration is a standard. The latter two kind of function’s gas flow amount is 1~1.2L/min, the ozone concentration to increase.
According to having the ozone principle to be possible to know, the high pressure which produces by the ozonizer disturbs not allow to neglect in this system. This kind of high pressure mainly through the conduction coincidence’s way disturbance linear power source’s stability, simultaneously will have certain disturbance to control system’s high frequency part - - monolithic integrated circuit.
Air pump module
According to the related request, the air pump power source which selects is the AC220V/50Hz power frequency power source, the power is 5~9W, the air output is 1.2L/min. The principle of work is actuates one kind of special diaphragm through the electromagnetic oscillation to produce the power. Has the module with the ozone to compare, this module produces the disturbance are few. Because the voltage is low, therefore the electric field disturbance is not intense; The magnetic field disturbance aspect, the electric motor work iron core will affect through the leakage other modules. But because the magnetic field frequency is not high, has not achieved the MHz level, therefore the magnetic field disturbance may not need nearly to consider outside certain scope.
Power source module
The mains input exchanges 220V/50Hz for the city electricity; The power source outputs must give 4 part power supplies:
* monolithic integrated circuit’s work power source - - directs current 5V;
* ozonizer’s work power source - - exchanges 220V/50Hz;
* air pump’s work power source - - exchanges 220V/50Hz;
* relay’s work power source - - directs current 12V.
The power source module design’s quality direct relation monolithic integrated circuit system’s work stability, in this design system, the power source module’s design has the following several questions: Ozonizer’s high voltage will have the influence to monolithic integrated circuit’s work, simultaneously will direct current the regulated supply to 5V also to have certain disturbance; The air pump module will create the electromagnetic interference, will attach through the radiation coupling to the signal transmission line, will have the possibility to cause the misoperation, will create controls inaccurate; The spatial existence’s electromagnetism affects under the working conditions each kind of disturbance to be able to join to the power source input end, moreover the city electricity is not the pure 220V alternating current supply, also will follow some peak wave. Therefore has used the massive antijamming measure in power source’s design.
LED and keyboard module
Establishes each kind of working pattern through the keyboard, when chooses treats the vaginitis key, the procedure automatic cut over to treats vaginitis’s ozone concentration and the default operating time. The user may also establish the treatment time through keyboard the length.
AVR monolithic integrated circuit’s I/O line complete belt may establish on pulls the resistance, therefore may not need to meet the resistance, but earths directly; When has not pressed the keyboard, all inputs the high level, if presses some pressed key, this pressed key corresponding port will be pulled lowers for the low level input.
System software design
In this system, ATmega8L-8PI uses the C language under the ICCAVR environment the compilation and the translation, mainly completes to the keyboard carries on the scanning, reads in the keyboard condition, and outputs each condition to four nixietubes on demonstrated that simultaneously MCU outputs the control signal on the power panel. Including master routine, keyboard scanning subroutine, demonstration subroutine, various pressed keys function subroutine, print subroutine and so on. After the source code warp knitting translates into the Intel hexadecimal system document, may internal dodge the fast/electricity cleaning program memory through the UART serial port direct loading to ATmega8L-8PI, and may carry on the online debugging and the revision, raised the development efficiency greatly. Master routine flow chart as shown in Figure 3.
Figure 3 Master routine flow chart.
After master routine start replacement, first is transfers the initialization subroutine to carry on the input output definition and the parameter initialization to the related IO mouth; Then carries on the keyboard scanning (including to vibrate processing), then basis keyboard keycode value execution corresponding function, when the end of job entered the sleep condition, if the no-operation surpassed certain time, then the system will also be at the sleep condition, the big reduction used electricity the loss.
Has also used the software antijamming measure in the software aspect, like watch-dog, instruction redundancy, sleep antijamming and so on. On software’s antijamming measure adds on the hardware antijamming technology is the medical curer function realizes the reliable safeguard stably.
Treats meter’s EMC test
With entire function computer tolerant tester TRANSIENT-2000, “the medical ozone therapy meter” the safety performance and the resistance to interference has carried on the test to the design. The function testing result and the resistance to interference test result see Table separately 1 and Table 2 shows.
Conclusion
This article introduced the medical gynecology department ozone therapy meter, take high performance AVR monolithic integrated circuit ATmega8L-8PI as the master control center, simplified the electric circuit, saved the cost, and has used each kind of hardware and the software antijamming measure, raised the systems operation speed and the stability effectively. The test result proved that this article designs medical gynecology department ozone therapy meter movement stable reliable, system antijamming ability, portable practical, has provided one kind of convenience effective family therapeutic schedule for the general gynecology department illness sickness patient.
Reference:
1. Wei Xu and so on, raises the ozonizer arc chamber efficiency the research, the electrician electrical energy new technology, 1998.2:46-49
2. Tang is outstanding, series resonance type DBD ozonizer power source’s research and development, Hunan University publishing house, 2004.
3. Bao Xiurong, Wang Nan, AVR monolithic integrated circuit’s characteristic and application, Inner Mongolian science and technology and economical publishing house, 2004.6:51 - 52
4. Careless Canadian will, monolithic integrated circuit observation system antijamming design, Chongqing Industry and commerce college newspaper (natural sciences version), 2005, 22(1): 59-62.
5. Zhao Xiaohui, in intelligent measuring appliance monolithic integrated circuit antijamming measure research, Liaoning normal junior college journal, 2002,4(3):93-95.
6. Huang Yong is handsome, in Zhang Xue, thanks Hsin Kang, the monolithic integrated circuit embedded system’s reliable discussion, the farm machinery research, 2005,(3):89-91
