CN107883619A

CN107883619A - A kind of small refrigerant recycling machine TT＆C system and method

Info

Publication number: CN107883619A
Application number: CN201711066223.8A
Authority: CN
Inventors: 张新亮
Original assignee: Chongqing Industry Polytechnic College
Current assignee: Chongqing Industry Polytechnic College
Priority date: 2017-10-30
Filing date: 2017-10-30
Publication date: 2018-04-06

Abstract

The invention belongs to refrigerant control technology field, disclose a kind of small refrigerant recycling machine TT＆C system and method, detected respectively by pressure sensor 1, sensor 2 and sensor 3 0.6MPa, 1.0MPa, -0.06MPa pressure raising and lowering change direction；The object of support is measured using the LM324 discharge circuits of electronic scale module；The data of pressure sensor 1, sensor 2 and sensor 3, the detection of LM324 discharge circuits are handled using single-chip microcomputer；TT＆C system includes single-chip microcomputer, pressure sensor module, electronic scale module etc..Reused after refrigerant-recovery of the present invention, placed under repair plus to discarded refrigerator and air conditioner, generate preferable economic benefit；The small refrigerant recycling machine TT＆C system of present invention design low cost, improve the automaticity and operability of recycling machine.

Description

A kind of small refrigerant recycling machine TT＆C system and method

Technical field

The invention belongs to refrigerant control technology field, more particularly to a kind of small refrigerant recycling machine TT＆C system and side Method.

Background technology

In recent years, with society the small-type refrigeration appliance such as development and growth in the living standard, refrigerator and air conditioner recoverable amount, Demand and discarded amount are all very big, and are also increasing year by year.But it is exactly greenhouse because refrigerant is not Ozone depletion material Gas, all it is the thing of the energy-saving and emission-reduction of national requirements recovery, it should reclaimed.Although the refrigerant in every refrigerator and air conditioner contains Amount is few, but with the rapid increase of refrigerator and air conditioner dead volume, the refrigerant total amount of discharge can also increase rapidly, if be not added with With recovery, an important environomental pollution source will be turned into.

In recent years, with society the small-type refrigeration appliance such as development and growth in the living standard, refrigerator and air conditioner recoverable amount, Demand and discarded amount are all very big, and are also increasing year by year.But because or refrigerant is Ozone depletion material, or be Greenhouse gases, it is the thing of the energy-saving and emission-reduction of national requirements recovery, it should reclaimed.Although the refrigerant in every refrigerator and air conditioner Content is few, but with the rapid increase of refrigerator and air conditioner dead volume, the refrigerant total amount of discharge can also increase rapidly, if not Reclaimed, an important environomental pollution source will be turned into.Therefore, the development of small refrigerant recycling machine has larger ring Protect meaning.

Small refrigerant recycling machine is primarily adapted for use in small-sized refrigerating maintenance such as domestic refrigeration maintenance industry.Because refrigerant returns It can be recycled after receipts, reclaim that the people of refrigerant is lucrative, they will have demand, and small-sized system at the recycling machine to practicality Cool equipment quantity is very big, maintenance practitioner it is numerous, therefore, small refrigerant recycling machine will have larger market demand and Sales volume, its producer and user to recycling machine can bring good economic benefit.

The cost of sensor is often much higher than single-chip microcomputer cost in actual applications, and higher than market to relevant device Price positioning, which constitute single-chip microcomputer broader applications a bottleneck.Solves the approach of this problem, first, can develop more The sensor of low price；Second, using the computing capability of single-chip microcomputer, the ability of sensor is improved with the method for digital processing, Make it the needs for meeting automatic control system in integration capability；Third, facing actual capabilities and constraints, coordinate engineering The requirement that invention exploitation side and Control System Design side develop to single-chip computer control system, make engineering invention exploitation side to control system The requirement of system meets prior art feasibility condition, and both sides find one on the basis of engineering invention basic goal is reached and mutually given in The equalization point of step.But this requires that design on control circuit personnel have other professional knowledge, and can be with other professionals very Link up well.

In summary, the problem of prior art is present be：

Prior art can not be to refrigerator and air conditioner refrigerant-recovery；Cause environomental pollution source；Current refrigerator observation and control of Air conditioning system Sensor price it is very high, particularly electronic scale and pressure sensor can not reclaim huge profit use；Cause refrigerator and air conditioner cost very It is high；And existing small refrigerant recycling machine environment protection significance and economic implications are poor.

The content of the invention

The problem of existing for prior art, the invention provides a kind of small refrigerant recycling machine TT＆C system and side Method.In the prior art, although in TT＆C system single-chip microcomputer and electronic component it is inexpensive, the price of sensor is universal It is very high, particularly electronic scale and pressure sensor.The present invention by rationally change a social system pressure sensor, conversion measuring method and fully The measures such as the data-handling capacity using single-chip microcomputer, system is reduced to electronic scale and the performance requirement of pressure sensor, so that Their cost is reduced, solves this problem.This is also maximum innovation of the invention.

The present invention is achieved in that a kind of small refrigerant recycling machine investigating method, the small refrigerant recycling machine Investigating method detects 0.6MPa, 1.0MPa, -0.06MPa pressure by pressure sensor 1, sensor 2 and sensor 3 respectively The change direction of raising and lowering；The object of support is measured using the LM324 discharge circuits of electronic scale module；Utilize list Piece machine is handled the data of pressure sensor 1, sensor 2 and sensor 3, the detection of LM324 discharge circuits.

Further, method is measured to the object of support using the LM324 discharge circuits of electronic scale module and uses arithmetic Mean value method；For：

Extremum principle is asked to obtain by function of a single variable

In formula：The arithmetic mean of instantaneous value of Y----n sampled value；

Xi---- ith sampled values；

N---- sampling numbers.

Further, the method that the data that single-chip microcomputer detects to LM324 discharge circuits are handled includes：

Using one of the single-chip microcomputer interrupt function constantly to work automatically carry out LED charactrons and diode displaying, Electronic scale weighing, recovery Timer Controlling；Specifically include：

When interrupting every time, the measuring circuit sampling for the sensor that weighed to scale once obtains one 8 two by analog-digital converter System number, continuous ten times sampling and analog-to-digital conversion after obtain ten numbers, averaged after then being added up to this ten numbers, from The decimal number of ten three obtains the decimal number of one more than four.

Another object of the present invention is to provide a kind of small refrigerant recycling machine TT＆C system to include：

Single-chip microcomputer, for carrying out observing and controlling to small refrigerant recycling machine；

Reset circuit module, is connected with single-chip microcomputer, the reset for single-chip microcomputer；

Crystal oscillating circuit module, is connected with single-chip microcomputer, for producing crystal oscillator frequency；

AD conversion module, it is connected with single-chip microcomputer, first with instruction one analog input channel of selection, then produces one and open Dynamic signal makes START pins obtain starting impulse, starts to choosing passage to change；End signal is sent after conversion end, and It is high level to put E0C pins, applies for signal as interrupting；When there is high level at 0E ends, the digital quantity changed is read；

Pressure sensor block, be connected with single-chip microcomputer, for detect 0.6MPa, 1.0MPa, -0.06MPa pressure rise and The change direction of decline；

Electronic scale module, is connected with single-chip microcomputer, and the object of support is carried out using the LM324 discharge circuits of electronic scale module Measurement；

Keyboard structure, it is connected with single-chip microcomputer, for inputting control parameter and monolithic processor resetting；

Compressor operation control module, is connected with single-chip microcomputer, a control level signal is exported by single-chip microcomputer, through driving electricity The road promotion actuating of relay is switched on or switched off the 220V AC powers of compressor, controls the start-stop of compressor；

Display module, it is connected with single-chip microcomputer, including eight seven sections of LED charactrons, eight light emitting diodes；For showing list Piece machine running status；

Buzzer warning drive module, is connected with single-chip microcomputer, using audible alarm member of the electromagnetic buzzer as error Part；Alarmed when being broken down for single-chip microcomputer；

Power module, it is connected with single-chip microcomputer, power supply is provided to the normal work of all devices.

Further, the small refrigerant recycling machine TT＆C system also includes：

Superpressure safety switch module, when hypertonia, automatically shut down the power supply of compressor.

Further, the pressure sensor block includes：

Sensor 1 and sensor 2, the change direction of the pressure raising and lowering for detecting 0.6MPa, 1.0MPa；

Sensor 3, the change direction of the pressure raising and lowering for detecting -0.06MPa.

Advantages of the present invention and good effect are：

The small refrigerant recycling machine of the present invention has environment protection significance.Moreover, reused after refrigerant-recovery, plus pair Discarded refrigerator and air conditioner places under repair, and generates preferable economic benefit.

The present invention is to apply existing detection technique and equipment, automatic control technology, singlechip technology and structured program The small refrigerant recycling machine TT＆C system of design method design low cost, improve the automaticity of recycling machine and operable Property.

The present invention has further the advantage that：

Require that analysis determines recycling machine observing and controlling system according to the mechanical structure of refrigerant recovering machine, operation principle and control The detection of the function of system, such as signal and display, the setting of mode of operation, the setting of function button, the display of failure and alarm.

According to the functional requirement of recycling machine TT＆C system, its structural principle block diagram is devised.

According to the structural principle block diagram of recycling machine TT＆C system, using AT89C51 single-chip microcomputers as core, its hardware is devised Circuit, such as Transducer Signal Detecting Circuit, A/D convertor circuit, compressor Control Cprant, keyboard signal input circuit, display electricity Road, alarm drive circuit, reset circuit and crystal oscillating circuit etc..

According to the hardware circuit of the operation principle of recycling machine, control requirement and TT＆C system, using Structured Programming Method and C language programming, devise the control software of TT＆C system, including primary control program, the Working mould such as manual, timing, automatic The control program of formula.

According to recycling machine TT＆C system design of hardware and software, it is made and tested.Test result shows that design accords with Close and require, the control needs of recycling machine can be met.

Brief description of the drawings

Fig. 1 is small refrigerant recycling machine TT＆C system schematic diagram provided in an embodiment of the present invention.

In figure：1st, single-chip microcomputer；2nd, reset circuit module；3rd, crystal oscillating circuit module；4th, AD conversion module；5th, pressure sensing mould Block；6th, electronic scale module；7th, keyboard structure；8th, compressor operation control module；9th, display module；10th, buzzer warning drives Module；11st, power module；12nd, superpressure safety switch module.

Fig. 2 is small refrigerant recycling machine TT＆C system hardware configuration the general frame provided in an embodiment of the present invention.

Fig. 3 is reset circuit figure provided in an embodiment of the present invention.

Fig. 4 is crystal oscillating circuit module map provided in an embodiment of the present invention.

Fig. 5 is ADC0809 pinouts provided in an embodiment of the present invention.

Fig. 6 is A/D converter provided in an embodiment of the present invention and 8051 connection circuit diagram.

Fig. 7 is precision voltage source provided in an embodiment of the present invention and 0809 Mating graph.

Fig. 8 is the program flow diagram of AD conversion provided in an embodiment of the present invention.

Fig. 9 is pressure sensor 1 provided in an embodiment of the present invention, 2 principle assumption diagrams.

Figure 10 is the structure chart of sensor 3 provided in an embodiment of the present invention.

Figure 11 is final small refrigerant recycling machine mechanical construction drawing provided in an embodiment of the present invention.

Figure 12 is photoelectric sensing amplifying circuit schematic diagram provided in an embodiment of the present invention.

Figure 13 is electronic scale module hardware basic circuit diagram provided in an embodiment of the present invention.

Figure 14 is LM324 provided in an embodiment of the present invention pinouts.

Figure 15 is typical in-phase amplifier application circuit provided in an embodiment of the present invention.

Figure 16 is electronic scale module amplification circuit diagram provided in an embodiment of the present invention.

Figure 17 is shake oscillogram caused by mechanical key provided in an embodiment of the present invention.

Figure 18 is compressor operation control module figure provided in an embodiment of the present invention.

Figure 19 is display module circuit diagram provided in an embodiment of the present invention.

Figure 20 is buzzer warning drive module figure provided in an embodiment of the present invention.

Figure 21 is power module circuitry figure provided in an embodiment of the present invention.

Figure 22 is principal function flow chart provided in an embodiment of the present invention.

Figure 23 is setting subroutine flow chart provided in an embodiment of the present invention.

Figure 24 is interrupt function provided in an embodiment of the present invention (explicit function, electronic scale weighing function, timing function) Flow chart.

Figure 25 is the flow chart of electronic scale weighing function provided in an embodiment of the present invention.

Figure 26 is the program flow diagram of manual mode module provided in an embodiment of the present invention.

Figure 27 is the flow chart of timing mode module provided in an embodiment of the present invention.

Embodiment

In order to make the purpose , technical scheme and advantage of the present invention be clearer, with reference to embodiments, to the present invention It is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not used to Limit the present invention.

Below in conjunction with the accompanying drawings and specific embodiment is further described to the application principle of the present invention.

Such as Fig. 1, small refrigerant recycling machine TT＆C system provided in an embodiment of the present invention includes：

Single-chip microcomputer 1, for carrying out observing and controlling to small refrigerant recycling machine；

Reset circuit module 2, is connected with single-chip microcomputer, the reset for single-chip microcomputer；

Crystal oscillating circuit module 3, is connected with single-chip microcomputer, for producing crystal oscillator frequency；

AD conversion module 4, is connected with single-chip microcomputer, first with instruction one analog input channel of selection, then produces one Enabling signal makes START pins obtain starting impulse, starts to choosing passage to change；End signal is sent after conversion end, Juxtaposition E0C pins are high level, apply for signal as interrupting；When there is high level at 0E ends, the digital quantity changed is read；

Pressure sensor block 5, is connected with single-chip microcomputer, for detecting 0.6MPa, 1.0MPa, -0.06MPa pressure rising With the change direction of decline；

Electronic scale module 6, is connected with single-chip microcomputer, and the object of support is entered using the LM324 discharge circuits of electronic scale module Row measurement；

Keyboard structure 7, is connected with single-chip microcomputer, for inputting control parameter and monolithic processor resetting；

Compressor operation control module 8, is connected with single-chip microcomputer, a control level signal is exported by single-chip microcomputer, through driving The circuit promotion actuating of relay is switched on or switched off the 220V AC powers of compressor, controls the start-stop of compressor；

Display module 9, is connected with single-chip microcomputer, including eight seven sections of LED charactrons, eight light emitting diodes；For showing Single-chip microcomputer running status；

Buzzer warning drive module 10, is connected with single-chip microcomputer, using audible alarm of the electromagnetic buzzer as error Element；Alarmed when being broken down for single-chip microcomputer；

Power module 11, is connected with single-chip microcomputer, and power supply is provided to the normal work of all devices.

The small refrigerant recycling machine TT＆C system also includes：

Superpressure safety switch module 12, when hypertonia, automatically shut down the power supply of compressor.

The pressure sensor block 5 includes：

The application principle of the present invention is further described with reference to TT＆C system hardware design.

1st, system hardware structure the general frame

Small refrigerant recycling machine TT＆C system hardware configuration the general frame is as shown in Figure 2:

There are 4KB program storage and 128KB RAM, the software of the TT＆C system for invention of breaking even inside 8051 single-chip microcomputers System uses, so not having to external memorizer.Using internal storage, then 31 pin EA connect high level, are connected with+5V power supplys.This System uses AT89S51, and 8051 program can be run on such chips completely, but it can be programmed using 5V voltages Write-in, debugging are more convenient.

2nd, reset circuit module：As shown in Figure 3.

There is high level can on the RST pins of 51 single-chip microcomputers to reset.In order to ensure resetting, this time is general Extend in more than 10ms.

The repositioning method of conventional single-chip microcomputer has upper electricity to automatically reset and two kinds of button hand-reset by principle point.

AT89S51 the 9th pin is reset pin RST, and automatic power-on reset circuit is realized again using electric capacity charging Position.Reset circuit is connected on the pin preset pin of single-chip microcomputer the 9th, in the moment that single-chip microcomputer switches on power, power supply is equivalent to one Equivalent to short circuit, the current potential at RST ends is identical with Vcc, is all+5V for individual alternating current, electric capacity both ends.With the charging of RC circuits, RESET current potential can be gradually reduced, as long as ensureing that the time that RESTE is high level is more than 10ms just energy normal resets.

Hand-reset only needs a switch or button power-up resistance can.As long as hand-reset is by the button in Fig. 3 Switch, so that it may so that RST pin obtain a high level, so that single-chip microcomputer carries out reset operation by the instruction of people.

3rd, crystal oscillating circuit module：

Crystal oscillating circuit is as shown in Figure 4：

Using 89S51, crystal oscillator frequency uses 12MHz up to 24MHz, TT＆C system of the present invention.

4th, AD conversion module：

1) selection of AD analog-digital converters and performance

The many factors such as the speed, precision and cost requirement of AD conversion sensing circuit are considered from the present invention, selected ADC0809 analog-digital converters.Analog-digital converter is：

ADC0809 is the tunnel simulation input of successive approximation 8, the a/d converter of 8 bit digital quantities output.

As CLK=500kHz, conversion time is 128 microseconds；

Maximum non-adjustable error is less than ± 1LSB；

Single+5V power supplies, simulation input scope is 0~5V.

Zero point and full scale adjustment need not be carried out；

ADC0809 pins are as shown in figure 5,8 tunnel analog channels share an A/D converter, by ADD A, ADD B, ADD C Encode selector channel number.According to 0809 each pin function, the course of work for obtaining ADC0809 progress analog-to-digital conversions is：Use first One analog input channel of instruction selection 0809, then producing an enabling signal makes START pins obtain starting impulse, opens Begin to choosing passage to change.0809 sends end signal after conversion end, and juxtaposition E0C pins are high level, and the signal can be made Apply for signal to interrupt；When there is high level at 0E ends, then the digital quantity changed can be read.

2) AD conversion sensing circuit designs

Fig. 6 is A/D converter and 8051 connection method of the present invention, and design is as follows：

A, 0809 it is connected with the signal of electronic scale sensor amplifier

0809 IN0, the voltage signal for coming with electronic scale sensor amplifier are connected, because ADC 0809 only has 8 Resolution ratio, 1LSB are the 1/256 of sensor full scale, and application claims electronic scale measures 0-2000 grams, in 0-255 gram quantity journeys When, 1 gram of 1LSB ≈, minimum indicating value can be shown to 1 gram；In 256--2000 gram quantity journeys, the resolution ratio of 8 can cause 1LSB =2000/255 ≈ 8,8 grams are increased close to, such resolution ratio is too coarse, and resolution ratio is improved again in order to save cost, can be with The method that micro computer calculating is handled is recycled to improve resolution ratio using multiple repairing weld, while meets the requirement of recycling machine.This It will be spoken of in the chapter of Software for Design one below.

B, IN1 is used to be connected with the signal of pressure sensor 1, and pressure sensor measurement range is -0.1 to arrive 1.1MPa, and 8 1LSB is 0.0047MPa during the analog-to-digital conversion of position, can meet TT＆C system requirement.

C, IN2 is used to be connected with the signal of pressure sensor 2, and pressure sensor measurement range is -0.1 to arrive 1.1MPa, and 8 Position analog-to-digital conversion can also meet to require.

D, tri- pins of the P1.0-P1.2 of 8051 P1 mouths connect with 0809 ADD A, ADD B, ADD C, with 8051 Tri- pins of P0.0-P0.2 of P1 mouths export 000-111 to select the switching of 0,809 8 tunnel analog channels.

E, 0809 ALE and START is connected together, and controlling for WR is exported by 8051 write signal.

F, 0809 OE is connected with 8051 read signal output RD, and controlling for RD is exported by 8051 read signal.

G, 0809 clock CLK is exported by 8051 ALE pins and provided, and 8051 ALE can export the six of clock crystal oscillator Divided pulse, if crystal oscillator is 12MHz, this output pulse frequency is exactly 2MHz.

H.0809 OUT1-8 exports connect corresponding with 8051 P1 mouth pins.

G.0809 VREF (+) meets 4.09V.This can produce this reference voltage with a TL431 precision voltage source, Circuit is as shown in Figure 7.The voltage of voltage adjustable accurate voltage source on 1 pin of regulation 431.Because using 5V power supplys to sensor Or during amplifier power supply, sensing or amplifier output voltage design are between 0-4.0V, so reference voltage 4.09V.

3) course of work of analog-to-digital conversion module：

Relevant control signal requirement according to hardware circuit with 0809 work, draw program flow diagram such as Fig. 8 of analog-to-digital conversion It is shown.The course of work is：It is low level to set WR first, by the low of the P1 mouths of the 1st analog channel selection signal write-in 8051 Three P1.0-P1.2.When WR is changed into high level, make ALE=1, address unblock, it is possible to selector channel, while make START= 1,0809 internal register is reset.When WR is changed into low level again, start AD conversion, and RD is set to low level, make 0809 OE (output allow) be low level, seal triple gate.It is delayed after 1mS, RD is set to high level, the OE for making 0809 is high electricity It is flat, it is possible to read transformation result from P1 mouths.Then the 2nd and the 3rd analog channel is selected to be AD converted successively.

5th, pressure sensor block：

Pressure sensor block also uses ADC0809A/D converters, with 51 single-chip microcomputers couple and operation principle and upper phase Together, simply sensor is different.The principle of transducing part is mainly explained below.

Because the present invention is not high to the required precision of pressure measxurement, cost is low again, and satisfactory low-cost pressure passes Sensor does not have off-the-shelf to be available for choosing.To solve this problem, the contrast through multiple schemes considers and experiment, finally devises The method changed a social system with conventional bourdon gauges solves, and needs to devise two schemes for different measurements, has Body scheme is as follows：

A) sensor 1 and sensor 2

By an annular potentiometer resistance piece on the dial plate of bourdon gauges, driven with spring-tube pressure list index The moving contact of electrokinetic potential device.The corresponding reading of pressure gauge can be thus obtained from the current potential of the moving contact of potentiometer. As shown in Figure 9.

Because the input resistance of A/D converter is very high, it is believed that electric current is not absorbed, potentiometer can use high resistant, It is required that linearly to get well, rotary resistance will measure small.Output voltage is likely to occur when connecing a small capacitances to reduce finger slips Bounce.Regulation R2 can make voltage output in suitable amplitude.

Although this structure cost is not high, because of the torque very little of general purpose pressure gauge driving pointer, this torque is not enough to The moving contact of potentiometer is effectively driven, so bigger error can be brought.Through multi-party investigation and experimental study, discovery pair This problem is hardly possible with low cost solution, but can improve in terms of two, and a method is adjustment potentiometer Moving contact causes that caused resistance is as far as possible small to the pressure of potentiometer resistance piece；Another method is by digital filtering and mistake The method that difference is corrected, i.e., appropriate data processing is carried out to the data measured using single-chip microcomputer, reduce error, this method details Discussed again in Software for Design below.Experiment confirms that the function required for present invention sensing can be completed by this processing.

B) sensor 3

During using above scheme, a very stubborn problem was once run into, is exactly the gauge measurement mistake when air pressure is near 0 Difference is too big.Through observation analysis repeatedly, find because pointer can not effectively promote swept resistance institute when air pressure is close to 0 Cause.To solve this problem, by Germicidal efficacy repeatedly, the measurement needs of recovery process are analyzed, after simplifying measurement request, Following method is employed to solve：Specially one pressure vacuum gauge of increase is specially right with the method for photoelectric sensing as sensor 3 Whether pressure, which reaches -0.06Mpa, is measured, and hardware configuration is illustrated in fig. 10 shown below, wherein；Light barrier is attached on pointer, light Quick resistance is placed in -0.06Mpa places, is irradiated by a light emitting diode during work.Surveying air pressure change when pressure gauge makes pointer When moving on at photo resistance, light barrier has blocked the irradiation light of light emitting diode, photo resistance increase (is typically increased number More than ten times), measure pointer from this change in resistance can and point to -0.06Mpa.Here it is pressure vacuum gauge in Figure 11 There is the design reason of two；And cost is considered, the mechanical structure for the recycling machine being finally made is as shown in figure 11,

Increase following change on the basis of principles above block diagram：Sensor 1, sensor 3 are made up of pressure vacuum gauge；Pass Sensor 2 is made up of pressure gauge；Sensor 4 is made up of pressure controller, and can be adjusted to makes power supply break when air pressure is more than 1 MPa Open, the air pressure of refrigerant in storage tank is not more than 1Mpa, to prevent storage tank from exploding.One electronic scale sensor of increase is used for measuring The refrigerant weight being recovered to.

The characteristics of such design allows for recycling machine normal course of operation：When the compressor starts of recycling machine start Air pressure at sensor 1 can should progressively decline in 0.6Mpa or so, later air pressure from about 0.6Mpa, be returned when dropping to -0.06Mpa Receipts process can terminate, and when not dropping to -0.06Mpa, photo resistance is always the low resistance state for having illumination, once there is high-impedance state, It is exactly that pressure reaches -0.06Mpa.It can then be measured as the eustasy speed of pressure by the swept resistance of sensor 1.

The change in resistance of photo resistance can form the signal feeding that comparator is become level height with an amplifier 89S51.Its circuit theory is as shown in figure 12.

Wherein, R1 is photo resistance, and D1 is light emitting diode, and U4A and R1-R4 forms comparator, when there is light irradiation R1 U1 exports low level, and U1 exports high level when light D1 light is blocked by light barrier.The P3.0 that this level is sent to 89S51 draws Pin, single-chip microcomputer can detect this change.

This problem can also have other solutions.Technically it is of course possible to the higher pressure sensing of use cost Device, but according to the market price of the invention feasibility analysis, this can largely effect on the market competitiveness in product future, on the other hand make The working media (refrigerant) of cryogen reclaimer recovery is more complicated, not only has a variety of chemical compositions, and be all high pressure height Permeability, it is high to many material dissolubilities, to be resistant to the refrigerant high pressure of multiple kinds simultaneously with less high cost The pressure sensor of Thief zone and dissolved destruction is nor nothing the matter.

6th, electronic scale module：

Electronic scale module hardware principle is illustrated in fig. 13 shown below, wherein the electric bridge that four resistance are formed is to claim weighing apparatus sensor Four strain resistors, when sensor is by Action of Gravity Field, their resistance value can change, because this four resistance constitute one Bridge-type resistance circuit, when not there is the object being weighed on sensor, four resistance keep balance, i.e., make in power supply V voltage Under, the voltage of the input of amplifier two is zero, and the output of amplifier is zero.Sensor employs low cost products, and model is MODEL:SH-A4,0-2000 grams of range.

When there is the object being weighed to put on a sensor, the change in resistance of resistance under stress, electric bridge is just no longer Balance is kept, at this moment differential voltage just occurs in amplifier in, and the weight of this voltage difference and measured object is into just Than, the voltage after the amplification of amplifier passes to the input of analog-digital converter 0809, through 0809 conversion after can from 0809 D0~D7 ends obtain digital quantity.

LM324 is to use extensive, cheap amplifier, and it can work well under 5V single supplies, and the present invention is not It is required that the gravimetric value that electronic scale output is negative, single supply op and the dc amplifier can without negative sense output meet to require, and It is just identical with microcontroller power supply and the amplifier uses 5V power supplys, one group of power supply can be shared, can thus make power supply simple Change, reduce cost.So the design can select LM324 amplifiers.

Figure 14 and table 1 are LM324 pinouts, pin function.

Table 1LM324 pin functions

A kind of LM324 typical in-phase amplifier application circuit Figure 15.

The requirement such as performance cost of TT＆C system of the present invention, the design are simple and inexpensive come comparison using LM324 Circuit, physical circuit is such as shown in Figure 16：

This circuit U13A, U13D have made two-stage amplification, and R10--13 is four strain resistors for claiming weighing apparatus sensor, U13C and Q2 forms constant-current source to weighing apparatus sensor power supply is claimed, and makes its work more stable.U13B is used to clamp down on electronic scale sensor For reference zero in ground potential, this can greatly reduce zero drift.R31, R28 and C8 are used to filter out interference, increase stability, RV2 and RV3 is used for the zero-bit for adjusting amplifier output.This circuit can reduce null offset, and have preferably linearly and stably Property, the amplifier of low cost can be used, achieves preferable effect.

7th, keyboard structure：

The button of TT＆C system of the present invention is less, to save cost, so only using the P2.2-6 of five buttons and P2 mouths Pin is directly connected to, and end/reset key is to make use of the button of hand-reset.

Button uses mechanical contact-type, because mechanical contact can produce shake when switching on and off, can so make The signal of input through keyboard is shaken, shaky time because mechanical switch characteristic is different and different, generally 5-10mS, people press The closing time of key is generally zero point several to several seconds during key.As shown in figure 17, when such case can make monolithic machine-readable keyboard state There is wrong ` to judge.Therefore should cancel key shake influence.

The conventional fluttering method that disappears has two kinds of hardware for jitters elimination and software for jitters elimination.

8th, compressor operation control module：

Compressor operation control module is as shown in figure 18.One control level signal is exported by single-chip microcomputer, through drive circuit The actuating of relay is promoted to be switched on or switched off the 220V AC powers of compressor, it is possible to control the start-stop of compressor.

9th, display module：

By functional requirement, it is necessary to which the element of luminescence display has eight seven sections of LED charactrons, eight light emitting diodes.One Seven sections of LED charactrons need the display (seven sections plus a decimal point) of eight line traffic control sections, and a line traffic control position shows.Eight luminous There are the LED charactrons of decimal point it is also possible to add a control with the control line of eight sections with one when diode is connected into common-anode The bit line of anode processed controls.It is of course possible to control a section or a bit line, but such eight with the pin of one 8051 LED charactrons share 8 × 8=64 bar pins, plus 8 bit line pins, along with eight diodes need 9 pins, so 81 lines are needed to control these displays altogether.For the sake of saving, these displays are handled with the method for dynamic scan here The work of device.Circuit theory diagrams are shown in Figure 19.

The present invention scanning circuit in, LED charactrons are common-anodes, the expression data/address bus of blue thick line, bus with Eight pins of the P0 mouths of 51 single-chip microcomputers connect, and are indicated with alphabetical a-h, and the negative electrodes of seven diodes is coupled with these of bus On line, the negative electrode of LED charactrons is also coupled with the corresponding line of bus, and eight driving gates together are then distinguished in order Connect with the bit line of eight LED charactrons, the single driving gate in the left side then with and together with light emitting diode anode Connect.Its operation principle is：Segment encode is served bus by 51 single-chip microcomputers in a certain order by P0 mouths, and another aspect single-chip microcomputer is controlled again Driving gate processed exports high level in certain sequence is powered corresponding LED to corresponding LED bit line, lights corresponding Section, is finally lighted and light emitting diode together, is so from left to right lighted, is gone round and begun again successively, when scan frequency is enough high When (be no less than 25 times/second), human eye just can be appreciated that all luminous elements are stably luminous.The scanning control of nine driving gates System is carried out high level " 1 " cyclic shift with shift register 164.

10th, buzzer warning drive module：

The present invention is using audible alarm element of the electromagnetic buzzer as error.The company of electromagnetic buzzer and single-chip microcomputer Connect as shown in figure 20, a NPN type triode driving buzzer is controlled with the P2.7 pins of P2 mouths.

When P2.7 exports high level, triode ON, buzzer sends alarm.

11st, power module；

Power supply has much relations, therefore the quality of system power supply to the normal work of all devices in single-chip computer control system Have a significant impact to the stability of SCM system.Power Management Design mainly considers power supply power consumption, the stability of supply voltage, output The problems such as power and power supply disturbance.

Because 8051 Typical operating voltages are 5V, so from 5V power supply, this power source design, design department are employed System should just select device of the operating voltage between 5V or 3V~5.5V.If zeroing requires, then the double electricity for having ± 12V should be used Source is preferable.The direct current that 12V is obtained after alternating current 220V civil power Transformer Rectifier can be used, this power rectifier can after 7805 voltage stabilizings Acquisition+5V power supplys, can be by the use of the right figure in Figure 21 as power circuit, and middle square is 7805 integrated regulators, and luminous two Pole pipe is used to indicate power supply status.

, will also be to the power supply after voltage stabilizing in order to obtain more stably dc source and effectively filter out the interference entered from power supply It is filtered, the filter circuit shown in left figure in Figure 21 is devised for this, right ± 12V and+5V power supplys is filtered.

12nd, superpressure safety switch module：

Because being the gas for having pressure, some or combustion explosion thing under refrigerant normal temperature, carry out recovery have it is bigger quick-fried Fried danger, so explosion-proof is the first requirement in this equipment operation.The main cause exploded is dress refrigerant Pressure of storage tank is too high.In order to prevent that pressure is too high, design of detecting and controlling system of the invention has the function of overpressure alarm.But for ten thousand nothings One loses, and has redesigned a superpressure safety switch, is controlled by Figure 11 pressure controller.When hypertonia, this switch energy The power supply of compressor is automatically shut down, the pressure of such refrigerant storage tank would not be too high, so as to prevent the generation of explosion accident. This is a circuit independently of single-chip computer control system, and it is not controlled by single-chip microcomputer, even if singlechip computer system goes out Problem it also can normally play a role.Thus it is equal to and has added " dual fail-safe ".Security can be made more guaranteed.

With reference to monitor and control system software design, the invention will be further described.

The design philosophy and method of Design of System Software：

Hardware and software combination could form a useful control system, and this is single-chip microcomputer and other traditional electronic equipments A very big difference, hardware seems a biological body, and software then imparts thought to this body, can make SCM system turns into a perfect system that can satisfactorily complete preplanned mission.Therefore the quality of the Software for Design of system is right The quality of SCM system has conclusive effect.Also, on important product, the mistake on a software may destroy Whole product.So Software for Design occupies critical role.Actually in many cases, the design of software, programming, needed for debugging The workload and spending wanted are more much more than the making of hardware.To improve software quality and efficiency, there now have been it is many into The methods and techniques of ripe software development, it should make full use of them to improve the efficiency of Software for Design and quality.Here is one The software approach useful to the present invention and design philosophy a bit.

One), using technologies such as structured design procedures, C language programming, IDEs.

Once occur " software crisis " sixties in the last century.Nineteen sixty-eight formally proposes and made in solving software crisis With " soft project " this term^[23].Today, soft project had a whole set of ripe Method and kit for, such as structuring Method, object-oriented method, Software tool, process, management method etc..The single board computer of early stage, is programmed using assembler language Afterwards, also assembly language program(me) is manually become into the machine code program that is made up of 0 and 1, be input in memory, modern program The technology and instrument of code automatic conversion and generation allow us to write program with high-level language such as C language, by computer software Downloaded to again in single-chip microcomputer as KEIL 51 is converted into machine code, not only hundred times thousandfold improve operating efficiency for this, and also causing can To write large-scale and complicated program, solve more bigger software tasks in production.

For the Software for Design of the present invention, first by the structured programming method of soft project, C language programming, one The deficiency of hardware can be made up, corrected a bit and improves the data processing technique of systematic function, and the technology such as IDE.

Two), digital filtering technique

So-called " digital filtering ", is exactly handled signal with some calculation procedures, to reduce interference signal useful Ratio in signal, substantially a kind of program filtering.Digital filtering has advantages below compared with analog filter:

Set respectively first, hardware need not be increased, can be with filter of multichannel " shared ".

Second, reliability is high, stability is good, and resistance matching problem is not present between each loop.

Third, signal that can be very low to frequency realizes filtering,

Fourth, by rewriting digital filter program, it is convenient to realize different filtering methods or change filtering parameter, than It is flexible to change hardware.

There are following six kinds for what the digital filtering method at general industry scene was commonly used：Median filtering method, arithmetic mean of instantaneous value Method, weighted average filter method, first-order lag filter method (digital filter method), anti-impulse disturbances compound filter method, limit filtration method.

Several filtering methods above are applied to the interference of different industry spots.The mean filter is applied to periodically Interference, middle position value filtering method and limit filtration method are applied to accidental impulse disturbances, and digital filter method is applied to high frequency and low frequency Interference signal, weighted mean method are applied to postpone larger controlled device.Consider cost, speed and required precision, this Invention employs method of arithmetical average in the software of electronic scale data processing.This method of brief introduction below：

Method of arithmetical average is to find the average value that the average value of a sampling samples as this, makes the value each with this The quadratic sum of error between sampled value is minimum, i.e.,

Extremum principle is asked to obtain by function of a single variable

Xi---- ith sampled values；

N---- sampling numbers.

Method of arithmetical average is applied to the smoothing processing to signal.When N values are larger, smoothness is high, but sensitivity is low；When When N values are smaller, smoothness is low, but high sensitivity.Concrete condition should be regarded and choose N, so as to evaluation time of both using tricks less, reached again best Effect.

Three), sampled data is corrected

The present invention because failing to find functional and low price sensor, so from the error in reading that sensor obtains compared with Greatly, significantly beyond the receptible degree of measurement institute of the present invention.In order to can be measured under existence conditions and Measurement data as well as possible is obtained, except employing some measures on hardware, have also been devised the skill corrected to data Art scheme.If the error of sensor measurement can be obtained, it is possible to which the data obtained to measurement are corrected accordingly.This survey Amount error can be drawn by the experiment to sensor assembly.The error measured, it is possible to pass through when measuring afterwards Data processing eliminates error from measurement result, makes final measurement more accurate.

With reference to main control module, the invention will be further described.

One), system software master-plan

The functional requirement of analysis system first, the i.e. function of analysis of small refrigerant recovering machine singlechip computer system will Ask, with reference to designed hardware configuration above, transform it into program flow diagram.During master-plan, using from the downward side of item Method, first since overall, with modular method, refine step by step, pay attention to keeping the independence of each module, strictly by soft project Method carry out, draw the flow chart of each module.Then the C programmer of each module is write again.

According to the functional requirement of TT＆C system and the requirement of refrigerant recovery process process, LED charactrons and light-emitting diodes Pipe should work and show always, and electronic scale and pressure sensor are also to work always, in addition in timing mode and automatic mold Setting time and timing are wanted during formula.Therefore, using the count internal interrupt function of 51 single-chip microcomputers, design is constantly started building certainly with one The interrupt function of work reclaims the work such as timer to carry out LED charactrons and diode displaying, electronic scale weighing, work, often Interrupt once with regard to once being shown, being weighed, as long as the interruption can per second for there are more than 25 times is fully shown.Need to set A display working area is put, interrupts fetched all from this area according to being shown, as long as each module of such recovery system is just every time The data that should be shown are put into working area can.Overall situation function can be made in the part that these each modules share, and Some corresponding global variables are set.Main flow chart set forth below and design philosophy.

Two), main control module flow chart and initialization：

According to the functional requirement of TT＆C system and there is overall situation function and global variable above, can be designed that most item layer Main control module, i.e. principal function flow chart：

1st, principal function flow chart：

Figure 22 is principal function flow chart.Wherein：The work of initialization is：Compressor is closed, opens to interrupt and opens display scanner uni Electronic scale, global parameter is set, pattern variable is set and puts initial value as standby mode (making start be manual mode), statement function etc..

2nd, subroutine flow chart such as Figure 23 is set.

3rd, the design and flow chart of overall situation function

Overall situation function is to interrupt 1 function (including LED explicit functions, electronic scale weighing function, timing function), delay letter Number, the subprogram that reports an error, scanning keyboard function etc..Their flow chart and main design idea are described as follows below：

1) initialization of Timer/Counters and the use of interrupt function.

There are two 16 programmable Timer/Counter T0 and T1 in 8051 series monolithics, they have timing and counted Two kinds of working methods, can be with their 4 kinds of mode of operations of programming Control.Mode of operation passes through to work method control register TMOD writes corresponding control word to control.Timer/counter control register TCON high nibble control Timer/Counter Startup.Control interruption is by allowing control register IE to write corresponding control word to be controlled to interrupting.

Initialization timing/counter is typically first wanted using interrupt function, initialization typically there are the following steps^[27]：

A writes control byte to TMOD, to determine working method.

B puts timing value or count value to TH0, TL0 or THl, TLl

C is to IE assignment, to determine whether out to interrupt

D makes TRl the or TR0 set of TCON registers, to start Timer/Counter.

Putting timing value or count value will a little calculate.Calculation formula is^[28]：

Mono- timing values of X=M/T during timing mode

The count values of X=M mono- during counting mode：

X is the initial value inserted in formula, and M is the maximum of counter, and T is the machine cycle, in mode of operation 0,1,2 respectively For the 13 of 2,16,8 powers.

The system design clock frequency is 12MHz, can be calculated according to above formula：

If using the bit timing device of Timer modes 1,16, timing is set to 10mS, then timing constant is：

Mono- timing values of X=M/T=2¹⁶- 10mS/1 microsecond=55536；

Hexadecimal is converted into obtain：X=D8F0H, thus set the initial values of T0 Timer/Counters as：

TH0=D8H, TL0=FOH；

2) design of interrupt function

Interrupt function flow chart is shown in Figure 24, and it can be spaced according to set time automatically, be operated, enter at regular intervals When row electronic scale weighing, timer travel, the work that shows charactron and lumination of light emitting diode.

The flow chart 25 of electronic scale weighing function therein.

Some explanation is made in design to the electronic scale weighing function in flow chart above：

The design uses the AD analog-digital converters 0809 of 8 output, and the digital quantity that it is exported is up to 255.But the present invention Scope of weighing be 0~2000 gram, it is necessary to which four integers, such 1LSB=2000 ÷ 255=7.84 gram, close to 8 grams, this is hard The quantization error that part determines.But require that electronic scale resolution ratio reaches 4 grams or smaller on the refrigerant recovery process of the present invention.In order to Meet that this is required and saves cost, the side of computer digital animation is used using the computing function of single-chip microcomputer in Software for Design The method of method digital filtering in other words solves this problem.Method of arithmetical average is used herein, specific method is as follows：

When interrupting every time, the measuring circuit sampling for the sensor that weighed to scale once obtains one 8 by 0809 analog-digital converter Bit, with regard to can obtain ten numbers after continuous ten samplings and analog-to-digital conversion, asked after then being added up to this ten numbers Average value, it is possible to obtain the decimal number of one more than four from the decimal numbers of ten three.Example is in for ten Three denary numbers between 190-200：198th, 199,197,198,197,198,199,199,196,198, arithmetic mean of instantaneous value is 197.9,1LSB=7.84 grams has been calculated above, and the weight that average values can obtain electronic scale and claim so is measured from this ten times For 197.9 × 7.84=1551.536 (gram), it is 1552 grams to be rounded up behind decimal strong point and take effective digital, thus obtains one Individual four denary numbers.So 1/10th of the original speed of measuring speed deficiency, sacrifice many speed, but can be by electronics Scale brings up to four decimal numbers of measurement from three decimal numeral abilities of measurement.It is about 8 grams of raisings from display minimum division value It it is one gram to minimum division value.This method also has application on some electronic instruments, applies this method now and is originally setting It is the requirement that can meet the present invention to measurement accuracy in meter.

This method can also be reduced or filtered out when reclaimer is used under adverse circumstances at the scene and inevitably done Disturb, improve systematic function.But this be to sacrifice speed as cost, it is sacrificial but in terms of the requirement from the present invention to speed of weighing This spot speed of domestic animal does not influence to use function.

Computer uses binary system, makees divided by ten calculating speed and unhappy, as long as making binary except rule is moved Position can, to enter this feature of count operation using single-chip microcomputer two, sampling can be used to be added for 16 times again divided by 16 Method.So processing can improve precision, but speed is without slow.

3) on the LED explicit functions in interrupt function：

Said in the design of hardware, the principle of display be with the method for scanning display, wherein, in hardware circuit be by Several light emitting diodes carry out display processing as a LED.So, eight LED add light emitting diode form one Be exactly the 9th, run-down will nine times to sending display data in LED segment code bus.

With reference to manual mode module, the invention will be further described.

Figure 26 is the program flow diagram of manual mode module.

To use in this mode and arrive six press keys, wherein terminate/function of reset key in be utilization in manual mode The reset function of 51 single-chip microcomputers, presses this key rear system and is initialized, really power-on reset state, so this module Without programming.The end of other patterns/reset key effect is herewith pattern,

Of the present invention group is further described with reference to timing mode module.

The flow chart 27 of timing mode module.

With reference to automatic mode module, the invention will be further described.

When using automatic operation mode, after start key, the compressor operation of recycling machine, control program passes according to relevant The signal of sensor makes compressor operation or stopped, not by pause key control, it is necessary to can just be stopped by reset key.

Wherein, the method for processing pressure sensor measurement data is：

Illustrated in hardware design, pressure sensor is changed a social system with pressure gauge, and application condition is big, mainly pressure gauge The pushing torque very little of pointer, it is impossible to efficiently against caused by the frictional resistance of swept resistance.In order to solve this problem, through grinding Study carefully, only three values of pressure gauge can be measured and handled, these three values are：0.6MPa, 1.0MPa, -0.06MPa, this As long as measuring the measured value of pressure sensor block in invention under these three pressure, and measure the trend of pressure change, so that it may full Sufficient control program uses.It is worth noting that 1.0MPa, be about safety measured value, when pressure exceedes it refrigerant storage Tank may explode, so compressor and bright superpressure trouble light are closed as 2 ＞ 1MPa of sensor, so this value should measure It is accurate and reliable.Find that the pushing torque of gauge hand can effectively promote cunning under this pressure in fortunately testing Move resistance and do not have too big problem.But in order to ensure reliability, devised on hardware independently of singlechip computer system Superpressure cut-off switch, even if the superpressure stopping function failure of single-chip computer control system, also can reliably close down compressor prevents from sending out Raw explosion accident.

It is the method with photoelectric sensing that the measurement of -0.06MPa this point whether is dropped to pressure, drops to -0.06MPa's Signal is to be sent into a high level to 89S51 I/O mouths, as long as SCM program carries out monitoring can to this signal.

With reference to standby mode module, the invention will be further described.

Because refrigerant recovering machine is new research and development product, may need to increase some new functions in further research and development, The function of analyzing software systems is easy to extend in the future, and spy devises a standby mode, needs to add other functions later and Can is put in this module.So do and not only facilitate, be also prevented from it and destroy the function and integrality of other original modules. In fact, standby mode simply makees an empty action.

After each module of software has designed, the program for writing each module is exactly last procedure.

With reference to the making of system, debugging and analysis, the invention will be further described.

The selection of system design developing instrument

Designing and developing for TT＆C system is helped using appropriate Computer-aided Design Technology and instrument, can be greatly The work of people is saved, produces the huge benefit of computer liberation human brain.For 51 series monolithics, also there are many exploitations Instrument and equipment, such as：The conventional exploitation software that support C language develops 51 SCM programs is just put on airs software company Compiler, the Windows collection of MICRO-C51 compilers, IAR companies and the exploitation of 2500A.D companies that DAVEDUNFIELD is released IDE Keil softwares^[30], the ASM51 of Intel Company, the Cybernetic Microsystem Inc companies in the U.S. Cys8051 etc., domestic has MedWin IDEs, big good fortune Integrated Development software etc..More complete integrated of function is opened Hair ring border can organically combine the various instruments needed for development and application software process, form one to people close friend side Just development environment.These instruments include editing machine, Advanced Compiler Tools, assembler, positioning/connector etc..Software and hard The instrument of part emulation has the EMUL5lXA-PC real-time on-line simulations device of Nahau companies, the Proteus of Labcenter companies of Britain Software, the replicating machine of the ten thousand sharp series monolithics of Insight SE-52HP types 51 of Nanjing production, etc..These are we provided Many good selections.

The design of 8051 singlechip application programs, early application is assembler language, and the advantage of assembler language is and hardware It is closely related, hardware capability can be conveniently realized, occupancy resource is small, it is fast to perform speed.But the code of assembler language is readable Difference, it can increase the difficulty of reading, programming and system maintenance upgrading, it is difficult to write big program.The C51 language tool developed later Have the various advantages of C language, such as programming module, code readability is good, easy care, transplanting and upgrading, although its generation Code execution efficiency is lower than assembler language, but current execution efficiency in most cases is very close to assembler language.Therefore use C51 language carries out the design of 51 SCM programs and has become a main flow.In view of C51 outstanding advantages, the design uses C51 languages Speech carries out software programming.

C51 adds many extended instructions for being used for 8051 single-chip microcomputers on the basis of standard C instructions are supported and formed, it Program structure is similar to writing for standard c program.People to having learnt C language well, a GPRS 51 single-chip microcomputer hardware knowledges, C Language and for 8051 C51 extended instructions with regard to successful program can be write out.

For C51 Complied executing, the μ Vision2 of KEIL companies are most generally used at present, are referred to as KEIL 51 more Software or KEIL, it is the Single Chip C Language compiler of German KEIL companies exploitation, and its predecessor is FRANKLIN C51, and it collects Into the multiple functions such as Document Editing, compiling link, invention management, window, instrument reference and software emulation management, its emulation In function, there are two kinds of simulation models：Software analog form and Target Board debud mode.Under software analog form, it is not necessary to User program under Target Board debud mode, can be attached to 8051 by 8051 single-chip microcomputer hardware with regard to that can complete procedure simulation debugging On single-chip microcomputer hardware system plate, communicated using the serial ports of single-chip microcomputer with PC to realize the real-time on-line simulation of user program, this Kind of mode makes user be not required to buy the hardware emulator of high cost just to reach same simulated effect^[34].These can be with It is greatly enhanced the development efficiency of user program.The design also selects exploitation debugging acids of the KEIL 51 as program.

The MCU download softwares of Guangzhou Shuan Long Electronics Co., Ltd.s exploitation are also all well and good, and it was used for the program generation after compiling Code is downloaded in 8051 single-chip microcomputers.

Also there are some softwares in terms of the emulation of hardware, wherein Proteus is a good software, and it is Britain The EDA tool software of Labcenter electronics companies research and development.Proteus not only can be with analogue simulation circuit, numeral electricity Road, analog hybrid circuit, can be emulated to Multiple Type single-chip microcomputer.ISIS intelligent principles figure input system therein is picture The design environment of schematic diagram and simulation hardware.It especially gives people to bring convenience, Proteus can be used in combination with KEIL and Joint carries out the artificial debugging of single-chip microcomputer soft and hardware, and this not needing single-chip microcomputer hardware system to adjust with regard to that can complete procedure simulation Examination, and completion simulation hardware include the emulation of electronic circuitry part.This brings very to the design of single-chip microcomputer and embedded system Big facility.

According to the present invention and the situation of EDA tool software above, the design of this TT＆C system is used as master from C51 language The programming language wanted, KEIL and Proteus, double imperial softwares are soft as main software translating, debugging, emulation and the instrument of download Part.From this combination it is also an advantage that being exactly that they can obtain the light version that can meet typically to require.In observing and controlling The emulation of the ten thousand sharp series monolithics of Insight SE-52HP types 51 of Nanjing production is also used in the debugging of system circuit board hardware Machine.

Input and debug with reference to program, the invention will be further described for emulation.

The result obtained by Design of System Software, then each program module is programmed by flow chart with C51 language respectively Obtain program, it is possible to input in single-chip microcomputer and run and debug.This programming can use in general text editor, use Editing machine inside KEIL is also very convenient.The C51 LISP program LISPs finished can be easily compiled with KEIL softwares, be linked, KEIL reports people to change it can be found that many mistakes for the program write with C51 language.Passed through afterwards just with KEIL compilings Then can be debugged on KEIL, at this moment if drawing corresponding single chip circuit with Proteus, with KEIL with Proteus associated working carries out the debugging of soft and hardware.Can more convenient and quicker.

Then, start KEIL and carry out software translating and debugging, first complete invention and create.Can is right in KEIL interface Program file is compiled, debugged, checking the work such as system mode, modification and emulation.It can be conveniently set up in KEIL disconnected Point, debugged using functions such as single step runs.

Corresponding circuit diagram can be drawn with Proteus, then the software and hardware of TT＆C system is entered with KEIL cooperations Row debugging.First startup optimization ISIS, LED display circuit is drawn with ISIS.

After preservation, start KEIL, compiled operation dispLED invention is opened, by KEIL Option for Debug under target options is arranged to Use proteus VSM MONITRE 51DRIVE, then can use KEIL with The function of Proteus joint debuggings.During using KEIL and the function of Proteus joint debuggings, KEIL various debugging, change, check system The functions such as state, emulation can be used, and operation at this moment can be intuitive to see on the circuit diagram of Proteus interface display Result, the high and low level that can be intuitive to see by artificial circuit figure on component pin, represented respectively with red, blue, no The level that can determine that can then represent that LED can be digital with luminescence display with grey.These bring very big to the debugging of circuit and program Convenience.Not only than only quick to 8051 convenient simulations with KEIL, than with reality circuit hardware using single-chip microcomputer serial ports with PC communication is also more directly perceived and convenient and swift to the real-time on-line simulation of user program to realize KEIL.

By artificial debugging, the problem of discovery, is modified and is debugged again, it is repeated multiple times after having no problem, it is possible to Carry out actual circuit fabrication and installation.Because current simulation software can not possibly also fully emulate actual circuit, so after emulation The actual circuit made again must also carry out the debugging and confirmation of software and hardware again, and actual circuit may also need to more modification.

After debugging is met the hardware circuit of requirement, PCB figures can also be obtained with Proteus ARES.Way It is：Schematic diagram is completed in ISIS, then modification encapsulation, is modified as the encapsulation of element the true form of equivalence element, adjusts After the encapsulation of whole good each element, it is possible to generate net meter file, be followed by net meter file importeding into ARES.Open ARES Afterwards, a chase first is drawn by circuit board size before placing element, all elements and line are arranged in chase.It can be used certainly Dynamic placing element instrument, but preferably first significant element is first placed by hand, then set wiring rule, such as setting to press again The width of wiring is set by the size of electric current, does one side or dual platen etc., then using self routing.Self routing is latter As also need to make point addition mounting hole, pad etc manually adjusts.Can prints making circuit board after intact, so Can installation elements, circuit test, modification circuit, software download, the progress system and program are debugged afterwards.

With reference to System Functional Test, the invention will be further described with analysis.

First, the general thought of System Functional Test

The method for carrying out functional test to system has a variety of, is tested after can system be all assembled, Ke Yifen Module testing, can also two methods combined use.In general, first sub-module test, the system that is then assembled into carry out overall The way of test, is easier to be tested, and the problem of being also easier discovery system and processing solve the problems, such as.The present invention uses This first sub-module test, is then assembled into the method that system carries out overall test.In addition, the characteristics of also according to software and hardware, right Some system elements have used the method tested respectively hardware and software.Some modules then need software and hardware knot Close to be tested.The useful method for carrying out functional test to system also has simulation method, can typically use simulation software, There is special emulator, first make system emulation, then make circuit and functional test is carried out to actual circuit.

The main method of testing of brief description and interpretation of result.

2nd, the test of hardware capability

(1) analog-to-digital conversion module part.

Individually AD analog-to-digital conversion modules can be tested, method is one voltage letter of analog input end input in AD Number, AD digital output is then observed, can be directly from the display of TT＆C system when the display function of system is normal Result after to AD conversion.During using emulation technology, because Proteus simulation softwares can emulate to hardware, so using it The low and high level of 0809 digital output pin can be intuitively shown, is intuitive to see the result of analog-to-digital conversion.Modulus Modular converter, which is tested, merely can not only make the test of hardware, and the premise of this test is the software adapted nothing of AD conversion By mistake, so this test can be checked software and hardware function simultaneously.

(2) pressure sensor part.

The pressure sensor of the present invention is changed a social system with pressure gauge, and the available certain air pressure of the test to pressure sensor is made With on pressure gauge, while specified voltage is connected to sensor, then observe the height of its voltage output.

Sensor 3 has used photoelectric sensing, and only p- 0.06MPa is measured.Method of testing to it is in this gas Pressure sees whether that relevant signal level can be exported.

(3) test of electronic scale module.

For electronic scale module, first the amplifier of electronic scale sensing module can be tested.Way is by R8 and R10 Connection with R12 disconnects, and from the input input direct voltage signal of first order amplification (U13D), observes amplifier magnification ratio With exporting change situation, it is adjusted correspondingly if undesirable.Amplifier section debug after again with AD conversion mould Block, which connects, to be tested, and it is last to observe the corresponding exporting change of digital quantity that 0809AD converters export under input voltage effect AD conversion module and single-chip microcomputer and display module are connected and tested, thus it can directly be seen that in certain input voltage The change of corresponding digital quantity down, precondition at this moment are that the software of single-chip microcomputer is adapted intact.Sensed in electronic scale Device and amplifier, a/d converter and single-chip microcomputer and display connect into an entirety when being tested, and can be put on electronic scale The object of upper constant weight, at this moment last position (minimum indexing for gram) of display can have variation, other higher positions Reading should be constant.

After superincumbent test is normal, then testing and debugging is carried out to the accuracy of electronic scale measurement, method is with different heavy The counterweight of amount is added on electronic scale and tested.Depending on the value of observation display and the difference of counterweight.By the present invention requirement this Difference should be not more than 16 grams (i.e. weigh 2000 grams when relative error 0.8%).Such as tens grams during certainly for small weighing When, 16 grams of error seems greatly a bit, but because the part tare weight of refrigerant-recovery fashionable dress refrigerant is general all more than 400 grams, The measurement range to small weighing will not be used, so the problem of relative error is larger during small weighing does not interfere with making for recycling machine With.

(4) single-chip microcomputer and LED such as show at the test of the hardware components of digital circuit.

As long as installation in general for small-sized circuit system circuit is errorless, element is intact, supply voltage is correct, just Will not be problematic.But it is noted that the frequency of crystal oscillator, whether starting of oscillation, to control circuit and the driving force of display the problems such as, in addition Voltage levels and stability to power supply, filtering out etc. for the interference from power supply should also be paid attention to.

3rd, the test of software function

The software of control system can say be whole system soul, the quality of a control system function is played decisive Effect, software be also one it is most complicated, need the most the most key part of making time.With hardware cost significantly Degree declines, and the cost of software often turns into R＆D costs highest part.Moreover, the software to reach a standard by test is yet not The complete correct of it is can guarantee that, especially for large-scale software systems, often " test can only find that software is wrong, no It can prove that its inerrancy ".So the test of software should be paid much attention to.

Software systems should be first tested modules respectively, system is then assembled into and carries out overall test, this Sample is easier to be tested and pinpointed the problems, and is also easier processing and solves these problems.The present invention first divides mould using this Block is tested, and is then assembled into the method that system carries out overall test.Test of the test except carrying out function to software systems, also The maloperation situation that may occur when should be actually used for system designs testing scheme, to find system to actual use The defects of in terms of the identification and processing of the middle faulty operation that may occur, it is correspondingly improved, to prevent in actual use Go wrong, particularly prevent great accident.

Then overall test after being assembled to software and hardware in next step, the experiment that finally should be also actually used and Examine.These are all highly important work, often can all find not detectable in test above ask in these tests Topic.

In testing, efficient approach can be put forward by being one using emulation tool.Can use KEIL and Proteus, Double imperial softwares etc. carry out compiling, debugging and the emulation of soft and hardware.

4th, System Functional Test result and analysis

Small refrigerant recycling machine TT＆C system shows by test, for control single chip circuit system in itself (no Including sensor) it can complete predetermined relevant function well.For example, the input signal of pressure sensor can use one Voltage signal is simulated, in this case system work quite can be with.But connecting actual pressure sensor input letter In number experiment carried out, situation caused by this limitation mainly due to sensor performance, but is surveyed so satisfactory Control system can complete original functional requirement.

The TT＆C system completed by design above also still has several drawbacks, have present or one masty Difficult point.Main problem is that：First, the mistake of measurement and sensing of the pressure sensor to pressure signal is formed with the pressure gauge transformation of the way Difference is larger, although employing the control function that some technical measures make system complete recycling machine, this still influences and made The about raising of recycling machine TT＆C system performance.Second Problem is exactly that electronic weighing scale A D conversion modules output digit is 8, can only 255 are shown to, and the weight measurement requirement of the present invention can survey 2000 grams, and require that the error of measurement can not be too big.

Present invention employs the software processing method of certain digital filtering, by test, obtains following result：

(1) four displays of the display of electronic scale, can be shown to more than 2000 grams, be allowed to show putting appropriate weight During four figures show 1000 to 2000 grams when, before three keep display it is digital constant, substantially only have last Numeral can change, and the resolution ratio of display can reach 1 gram, so meet the requirement that resolution ratio reaches 4 grams；

(2) minimum value of the numeral change of display can reach 1 gram, but more up to 8 grams, and this is that the limitation of hardware causes , reason is：The maximum number amount that ADC0809 is converted is 255, to measure and be shown as 2000, and this is 8 times of 250, It is exactly 0809 exporting change 1, display just change 8, so the minimum value of the numeral change of display should be 8 grams, this is that hardware is determined Fixed quantization error.Though 8 can be less than by handling this value by digital filtering, change minimum value is still more with 8, with ideal Situation still has bigger difference.But quantization error has obtained obvious reduction after software processing.

(3) the numerical calculation processing passed through in software, measurement error can reach less than ± 16 grams；This has been maximum weighing The 0.8% of 2000 grams；(general apparatus measures error is often determined by the percentage of maximum indicating value, and indicating value is pressed in indicating value hour The percentage error of calculating is larger to be allowed, and caused by the limitation of technology).

(4) electronic scale can delicately reflect the change of weight.

The requirement of reclaimer can be met in terms of this 4 points result.

First problem above can not still solve at low cost through repeatedly trial-production, have to try to find some other ways.By with problem The other professional's joint studies of group, determine to look for solution route from observation analysis removal process.Through research, discovery can be only Quasi- 0.06MPa, 0.6MPa, 1.0MPa these three points are surveyed, removal process can also be controlled.Thus use pressure gauge Changed a social system can to this 3 points sensors 1 measured, sensor 2 and sensor 3, make them and can measure pressure rise and under The change direction of drop, this had been described in above the 2nd chapter .5 sections.Thus solve substantially and use low cost pressure sensor To form the problem of TT＆C system.After tested, 0.6 and 1.0MPa error is measured in ± 0.05MPa, measurement -0.06MPa Error within 0.02MPa, the sensing requirements of TT＆C system can be reached.

By the processing of above method, by the experiment test to software and hardware, in general, small refrigerant recycling machine is surveyed Control system is capable of the relevant function of complete design requirement, while by cost of manufacture control within constraints, it is designed to Success is arrived.

With reference to summarizing, the invention will be further described with conclusion.

With the fast development of science and technology and electronic technology, computer technology, automation field has had highly developed Technology, equipment, method and device, wherein, although microcomputer and sensor, control and execution unit are in automatically controlling Particularly significant and crucial role is play, but these parts are formed to method, the instrument of an effective automatic control system Also it is particularly significant and indispensable.Such as the theory that computer controls, software engineering method, digital processing, electronic technology, electricity Gong Ji Art, measurement technology, machine word are made peace programming etc., and the methods and instruments of relevant CAD are all very It is important and indispensable, it is a good circuit and system high technical staff institute required technical knowledge and skillses.In the design of the present invention In, the methods and instruments of CAD, such as：The use of C programmer design, KEIL, Proteus etc., is substantially increased The efficiency designed and developed of software and hardware.In addition, Thought of Structured Design has highly important work to smoothly completing also for the present invention With.

On the other hand, one of difficult point of the invention Sensor Problem, because of the market prospective price limit cost of product, no Can use high price sensor, therefore and attempted the method changed a social system to pressure gauge, have also been attempted to inexpensive electronics The special data processing method of scale sensor and analog-digital converter.Pass through the biography to these " defective " under ordinary meaning Feel the transformation of the way of module, and digital processing is carried out using the computing capability of micro computer, be allowed to meet the requirement of recovery system.So as to Recycling machine TT＆C system is set to complete predetermined function under constraints, design work has obtained success.

Now, the single-chip microcomputer as " brain " of automatic control system is highly developed and cost price is suitable Low, it can be used for various needs and automatically controls and occasion and equipment in theory.But actually it is substantially only used for middle height The equipment of shelves, one of those important limiting factor is that the cost of sensor is often much higher than single-chip microcomputer cost, significantly high In price positioning of the market to relevant device.There is the solution method of three aspects to this problem：First, exploitation, design or the transformation of the way are more The sensor of low cost, second, using the computing capability of single-chip microcomputer, the ability of sensor is improved with the method for digital processing, is made The needs for meeting automatic control system in integration capability.Third, facing actual capabilities and constraints, engineering development is adjusted Requirement of the side to single-chip computer control system exploitation, makes engineering development side reach engineering invention root with Control System of Microcomputer exploitation side The equalization point that an interaction is given way is found on the basis of this target, such as the present invention is required in satisfaction recovery pressure measxurement requirement On the basis of change be exactly this equalization point.These should be the Important Thought of actual automatic control engineering invention exploitation.But It is that this requires that the technical staff of Circuits and Systems has other professional knowledge, can be with the good trench of the other professionals of engineering It is logical, including common language with technical elements etc., it is also necessary to there is the stronger ability of practice of starting.This is another in design work One harvest.

The cost for the requirement equipment developed by small refrigerant recycling machine can not be high, market when being set up the project according to 06 year Investigation and measuring and calculating, the manufacturing cost of small refrigerant recycling machine should be at 550 yuan, and 700 yuan or so of market price is advisable.So, The cost of mechanical part is removed, the manufacturing cost of single-chip computer control system part is limited in 200 yuan.So, how to reduce into This is also into an important design goal of this control system.This is harsh requirement and challenge of the market to cost.It is so-called most It is excellent should be it is optimal under constraints, win the market advantage under constraints.The present invention can in this cost into Realize design work(, laid the foundation for the marketization of next step new product.Its design is successful.

Inquire into and look forward to

Pressure gauge is a kind of widely used measurement instrument, and in general Bourdon tube pressure gauge price can be made very It is low, but the price of pressure sensor is not but low.It is many using the equipment of pressure gauge because pressure gauge is widely used, If the pressure sensor bid a low price can be developed, it can will energetically promote the popularization of single-chip microcomputer and embedded system technology should With allowing people to benefit from automatic control technology in a wider context.

Because Bourdon tube pressure gauge price can be made at a fairly low, technically highly developed, I feels The pressure sensor of developing low-cost will be a direction that can actually realize on the basis of it.My imagination is, can be by bullet Reed pipe formula pressure gauge is combined as an element for experiencing pressure, then with electronic technology and component, by spring-tube type pressure The deformation for the bourdon tube that the pressure change that table obtains is formed becomes electric signal output.Such pressure sensing easily realizes low cost Target, the data-handling capacity of single-chip microcomputer can also be utilized to improve the performance of this pressure sensor.

If the function of the calculating of micro computer, control and high-speed cruising can be utilized further to improve the function of recycling machine, example Such as try to make removal process carry out, using variable-frequency and variable-speed technology, singlechip technology existing in theory by a kind of optimal process It is entirely capable of realizing, but because cost limitation can not so be done at present.But the appearance and price in the future as the new device of new technology Decline, or the rising of recycling machine product price, it is possible to realization makes refrigerant recovering machine control system develop to higher performance Imagination.Such as：Future variable-frequency motor and the performance of frequency-variable module improve and prices, low cost pressure sensor occur With title weighing apparatus sensor, it is possible to applied to the performance on refrigerant recovering machine, greatly improving recycling machine.This is entirely possible.

It is huge good that although automatic control technology is brought in the extensive field such as industrial and agricultural production, scientific research, daily life Place and benefit, but the cost of sensor is often to single-chip microcomputer and an important limit of automatic control technology broader applications Bottleneck processed.To break this limitation bottleneck, the exploitation of the lower and practical sensor of more, more preferable, cost should turn into one Important R＆D direction.

The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention All any modification, equivalent and improvement made within refreshing and principle etc., should be included in the scope of the protection.

Claims

1. a kind of small refrigerant recycling machine investigating method, it is characterised in that the small refrigerant recycling machine investigating method leads to Over-pressed force snesor 1, sensor 2 and sensor 3 detect 0.6MPa, 1.0MPa, -0.06MPa pressure raising and lowering respectively Change direction；The object of support is measured using the LM324 discharge circuits of electronic scale module；Using single-chip microcomputer to pressure Sensor 1, sensor 2 and sensor 3, the data of LM324 discharge circuits detection are handled.

2. small refrigerant recycling machine investigating method as claimed in claim 1, it is characterised in that utilize electronic scale module LM324 discharge circuits measure method to the object of support and use method of arithmetical average；For：

<mrow> <mi>E</mi> <mo>=</mo> <mi>m</mi> <mi>i</mi> <mi>n</mi> <mo>&lsqb;</mo> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <msubsup> <mi>e</mi> <mi>i</mi> <mn>2</mn> </msubsup> <mo>&rsqb;</mo> <mo>=</mo> <mi>m</mi> <mi>i</mi> <mi>n</mi> <mo>&lsqb;</mo> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <msup> <mrow> <mo>(</mo> <mover> <mi>Y</mi> <mo>&OverBar;</mo> </mover> <mo>-</mo> <msub> <mi>X</mi> <mi>i</mi> </msub> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&rsqb;</mo> <mo>;</mo> </mrow>

Extremum principle is asked to obtain by function of a single variable

<mrow> <mover> <mi>Y</mi> <mo>&OverBar;</mo> </mover> <mo>=</mo> <mfrac> <mn>1</mn> <mi>N</mi> </mfrac> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <msub> <mi>X</mi> <mi>i</mi> </msub> <mo>;</mo> </mrow>

Xi---- ith sampled values；

N---- sampling numbers.

3. small refrigerant recycling machine investigating method as claimed in claim 1, it is characterised in that single-chip microcomputer is to LM324 amplifiers The method that the data of electric circuit inspection are handled includes：

The interrupt function constantly to be worked automatically using one of single-chip microcomputer carries out LED charactrons and diode displaying, electronics Scale weighs, reclaims Timer Controlling；Specifically include：

When interrupting every time, the measuring circuit sampling for the sensor that weighed to scale once obtains 8 binary systems by analog-digital converter Count, obtain ten numbers after continuous ten samplings and analog-to-digital conversion, averaged after then being added up to this ten numbers, from ten The decimal number of three obtains the decimal number of one more than four.

A kind of 4. small refrigerant recycling machine observing and controlling system of small refrigerant recycling machine investigating method as claimed in claim 1 System, it is characterised in that the small refrigerant recycling machine TT＆C system includes：

AD conversion module, it is connected with single-chip microcomputer, first with instruction one analog input channel of selection, then produces one and start letter Number START pins is obtained starting impulse, start to choosing passage to change；End signal, juxtaposition E0C are sent after conversion end Pin is high level, applies for signal as interrupting；When there is high level at 0E ends, the digital quantity changed is read；

Pressure sensor block, it is connected with single-chip microcomputer, for detecting 0.6MPa, 1.0MPa, -0.06MPa pressure raising and lowering Change direction；

Electronic scale module, is connected with single-chip microcomputer, and the object of support is surveyed using the LM324 discharge circuits of electronic scale module Amount；

Compressor operation control module, is connected with single-chip microcomputer, exports a control level signal by single-chip microcomputer, is pushed away through drive circuit Motor type relay acts the 220V AC powers for being switched on or switched off compressor, controls the start-stop of compressor；

Display module, it is connected with single-chip microcomputer, including eight seven sections of LED charactrons, eight light emitting diodes；For showing single-chip microcomputer Running status；

Buzzer warning drive module, is connected with single-chip microcomputer, using audible alarm element of the electromagnetic buzzer as error；With Alarmed when single-chip microcomputer breaks down；

5. the small refrigerant recycling machine TT＆C system of small refrigerant recycling machine investigating method as claimed in claim 4, its It is characterised by, the small refrigerant recycling machine TT＆C system also includes：

6. the small refrigerant recycling machine TT＆C system of small refrigerant recycling machine investigating method as claimed in claim 4, its It is characterised by, the pressure sensor block includes：