The anti- interference technique introduces
The interference problem is a machine to give or get an electric shock integral whole to turn system design and use process in the important problem that have to consider.Give or get an electric shock the work environment that the integral whole turns system in the machine in, existence a great deal of of electromagnetism signal, such as the Qi of the motion, strong electricity equipments of charged barbed wire net stop, high pressure equipments and the electromagnetism of the switch radiation etc., be when they produce electromagnetic induction and interference to pound at in the system usually disturb the normal movement of system, light result in system of unsteady, lowered the accuracy of system;Is heavy will arouse to control system to crash or the mistake act and result in the equipments damage or the Human body die or injure.
Section 1 produces the factor of interference
A, the definition of interference
The interference refers to the internal or external factor that badly influences to the normal work creation of system.Speak from the broad sense, the machine electricity integral whole turns the interference factor of system to include an electromagnetism interference, the temperature interference, degree of humidity interference and voice wave interference and vibration interference etc., in numerous interferences, the electromagnetism interference is the universal, and to control the system influence biggest, but other interference factors usually can a little bit easily solve in the way of some physicses.This stanza point introduces the related contents of electromagnetism interference.
The electromagnetism interference means in the process of working in appear under the influence of environment factor of some and useful irrelevant signal, and deliver harmful electricity variety to the system function or the signal phenomenon.These harmful electricity variety phenomena make the data of signal take place in a sudden the Tai change and enlarge an error margin and appear appearance and even make the whole system appear excrescent signal but arouse breakdown.For example spread a leading of feeling machine the line is influenced by air magnetic field outputly and respond to give or get an electric shock certainly will be bigger than to measuredly spread a feeling machine to output signal, make system judge out of order.
Two, form three main factors of interference
The formation of interference includes three main factors:Interference source, spread path and accept to carry a body.Three main factors aring in need of an any interferences can't produce.
1, interference source
Produce the equipments of interference signal be called an interference source, like transformer, can produce air electromagnetism signal after the electric appliances, microwave equipments, electrical engineering and without the rope telephone and high pressure electric wire etc..Certainly, the thunder and lightning, the sun and cosmos shoot line to belong to an interference source.
2, spread path
Spread path to mean spreading of interference signal path.The electromagnetism signal in the sky and straightly spreads, and have the dissemination of penetrability to be called a radiation method dissemination;Electromagnetism signal's asking for help of to lead the dissemination that the line streams into an equipments is called a conduction method dissemination.Spreading the path is an interference to spread and omnipresent main reason.
3, accept to carry a body
Accept to carry a body to mean that a certain link of equipments that be subjected to influence absorbed interference signal, and convert into the electric appliances parameter that results in the influence on system.Accepting to carry a body can not respond interference signal or weaken interference signal to make it be not improve the ability of anti- interference by the interference influence.Accept to carry an accepting of body process and become Ou to match, the Ou matches to is divided into 2 types and conducts Ou to match and radiates Ou to match.Conduct Ou to match to mean that the electromagnetism energy leads line or gathers through metal with the form of the electric voltage or the electric current the total component(is like capacitor, and transformer...etc.) Ou matches to accept to carry a body.Radiate Ou to match an electromagnetism interference energy to pass the space is matched with electromagnetism field form Ou to accept to carry a body.
Can see according to the definition of interference, the reason signal is an interference is that it can not call it as interference to the bad influence that the system results in, contrarily.Can know from the main factor of formation interference, get rid of three main factors in of whichever, will avoid interference.The anti- interference technique is the research and processing that aims at three main factors.
Three, the category of electromagnetism interference
The Ou that presses the interference matches a mode classification, the electromagnetism interference includes the following type.
1, static electricity interference
A great deal of object surface all existence static electricity electric charge of, especially equipments with the electricity control, the static electricity electric charge will form static electricity electric field in the system.The static electricity electric field will arouse the electric potential occurrence of electric circuit variety;Will match to produce interference through an electric capacity Ou.The static electricity interference still includes electric circuit surroundings article up accumulate the electric charge gathering to put to the electric circuit's leaking, greatly carry to flow output electric field of conductor(power line road) to pass to live on the Ou that the electric capacity places to deliver to the machine electricity integral whole disguise to match an interference etc..
2, the magnetic field Ou match interference
Big electric current surroundings magnetic field to machine electricity the integral whole turn an equipments back track Ou to match formative interference.Power line, electric motor, generator, power transformer and will produce this kind of magnetic field after electric appliances etc.s.The equipments that produces magnetic field interference usually accompanies with the interference of electric field at the same time, therefore unifies to be called electromagnetism interference again.
3, the electric leakage Ou match interference
It insulate electric resistance to lower but is flowed causable interference by the electric leakage.More worse environment or spare part function happens to deteriorate at the work condition, under the circumstance with aging spare part.
4, total resistance interference
The total resistance interference means each part of electric circuit is public resistance and Zu inside the power leading line resistance, ground to press to decline mutual Ou to match formative interference.This is widespreadly the machine to give or get an electric shock integral whole to turn system existent of a kind of interference.Such as figure 7-1 show of establish of connect a place type, due to connecting the existence of a ground of electric resistance connecting of three electric circuits a ground of electric potential obvious dissimilarity.When the I(or I and I) occurrence changes, the A, B and C orders of the electric potential immediately take place to change and cause each electric circuit of unsteady.
Figure 7-1 connect a ground of total resistance interference
5, the electromagnetism radiate interference
From various big power high repeatedly, medium repeatedly occurrence device and Gao of various electricity spark and radio station television station etc. creation repeatedly electromagnetic wave, to surroundings space radiation, form electromagnetism radiation interference.Thunder and lightning and astrospace will also have the electromagnetic wave interference the signal.
Four, the form of interference existence
In the electric circuit, interference signal usually with string mold interference and total mold interference the form and useful signal together deliver.
1, string mold signal
The string mold interference is to fold to add be measured the interference signaled of the signal, also call horizontal interference.The reason of the creation string mold interference includes the static electricity Ou to distribute electric capacity to match, the long line delivers of with each other feeling, space electromagnetism field the causable magnetic field Ou match, and the work with 50 Hzs repeatedly interference etc..
Give or get an electric shock integral whole to turn system in the machine in, it is a direct current(or change more slow-moving) to be measured signal, but interference signal usually is some miscellaneous and disorderly wave form and imply peak pulse, such as the figure 7-2 cs show, US in diagram means ideal test signal, UC means to physically deliver signal, the Ug means irregular interference signal.The interference may come from signal source inner part(the figure 7-2 as), may be also come from leading linear of respond.(figure 7-2 bs)
2, total mold interference
The total mold interference is usually meant to add to carry at the same time each importation signal connects to break of totally have of signal interference.Such as figure 7-3 show to examine a signal importation A|D conversion machine of two importations carry last of owned by public of electric voltage interference.Because the importation signal source and host compared long pull and inputed signal Us of the reference connect location and calculator to control a system importation to carry reference to connect an of location existence potential difference Ucm.This potential difference forms total mold interference in converting two importations of machine and carrying.With the calculator connect location for the reference order and add an importation and order the signal of the A for the Us+Ucm, add an importation and order and also has signal Ucm in the B.
The figure 7-2 strings of molds interference sketch map
Figure 7-3 total mold interference sketch map
The measure of section 2 anti- interference
Raising measure the most ideal method of anti- interference makes it not and outwardly produce interference or its interference influence and limit at allow of scope inside.Because car the complexity of the spot interference source, think to work up to make to all interference sources it not and outwardly produce interference, is almost impossible, also not realistic.Come from the interference of charged barbed wire net and the external world environment moreover, the machine electricity integral whole turns a product customer the interference source of the environment is also unavoidable.Therefore, develop in the product and applied in, in addition to mainly carrying on repressing an outside to some interference sources on the object being directly controled to some important interference sources, morely then try to repress the influence of the foreign interference in the product to promise system dependablely work.
Repressing the measure of interference is a lot of, mainly include to shield, insulate, filter wave and connect ground and software to handle etc. method
A, shield
Shield is make use of to conduct electricity or lead Ci material to make into of box-like in shape or hull-like in shape the space Ou of field shielding a body, surrounding interference source or interference object to cut off or weaken interference thus match passage and obstruct delivering of its electromagnetism energy.Pressing to need the property of interference field for shielding is different, can is divided into electric field to shield, the magnetic field shield to shield with electromagnetism field.
The electric field shields for the sake of the cancellation or represses because the electric field Ou matches causable interference.Usually conduct electricity good metal material of function to make to shield a body with the copper and aluminum etc..Shielding the body structure should as far as possible the integrity is tight and keep to goodly connect ground.
The magnetic field shields for the sake of the cancellation or represses because the magnetic field Ou matches causable interference.Hand over to change magnetic field to the quiet magnetic field and the low frequency, can make to shield a body with the material of Gao Ci Dao's rate, and promise that the Ci road is unimpeded.Repeatedly hand over to change magnetic field to Gao, because of main depend shield body hull the anti- magnetic field produced for flowing Wo livinging on feeling of body to have the function to reject original magnetic field.Choose material is also a good conductor, like copper, and aluminum...etc..
Such as figure 7-4 show of transformer, round a set of the outside that the line wraps to wrap the 1 F copper skin as to leak Ci short-circuit wreath in the transformer.While leaking a Ci to once wear short-circuit wreath, the feeling livings Wo to flow in the copper wreath, therefore will produce anti- Ci with offset part to leak a Ci, it makes transformer outside of the Ci weaken.Effect of shielding with shield amount of 1 Fs to have relation with each thickness.
Figure 7-4 transformers shield
Such as figure 7-5 show of in the coaxial cable, in bar of deliver to be subjected to electromagnetism interference in the process in the signal, established to shield a layer in the cable.The magnetic field of Xin line electric current creation is limited between the outside layer conductor and Xin line of in the space, can't spread coaxial cable of space.But the magnetic field interference signal out of the electric cable is in the Xin line of coaxial cable and outside layer in the middle of the conductor output interference electricity power the direction is same, make electric current an aggrandizement, 1 lets up but offsets mutually, the total electric current increases quantity to zero.Many correspondence electric cables still and just and outside wrap up the 1 F conductor thin film with the function that the exaltation shields outside electromagnetism interference.
Figure 7-5 coaxial cable sketch maps
1-Xin line 2-insulator 3-the outside layer lead line 4-insulate cortex
Two, insulate
The insulation means to make the interference source receiving the system insulation with open, make the useful signal deliver as usual, but interference Ou's matching passage be cut off and attain the purpose of repressing the interference.The familiar insulation method includes optoelectronics insulation, transformer to insulate and insulates after the electric appliances etc. method.
1, the optoelectronics insulate
The optoelectronics insulation makes with the light medium at insulate of both ends carry on signal to deliver of, the spare part used is an optoelectronics Ou to match a machine.Because the optoelectronics Ou matches machine while delivering an information, don't carry on direct Ou of telecommunication of its input and output to match, but is ask for help from light as the medium thing carries on Ou to match, as a result have stronger insulate and the ability of the anti- interference.Show to match the importation that the machine constitutes for general optoelectronics Ou such as the figure 7-6 as|output circuit.In the middle of controling system, it since can used to a general importation|output's insulation, also can replace pulse transformer to have circuit insulation and pulse to enlarge a function.Because the optoelectronics Ou matches the electricity characteristic that the tool has diode, triode transistor, it makes it able to expediently constitute various electric circuit.Again because it depends light the Ou match to deliver an information and make it has the ability of very strong anti- electromagnetism interference and gives or gets an electric shock integral whole to turn to acquire a very and extensive application in the product in the machine thus.
Figure 7-6 optoelectronics insulations and transformer insulate principle
A) the optoelectronics insulate b) the transformer insulate
Because light the Ou match a total mold of machine to repress compare big, have never touched point, life span long, easily match with, respond to speed with logic electric circuit quickly, small scaled, bear pound at and stable credibility, therefore gave or got an electric shock integral whole to turn system to especially get an extensive application in the number system in the machine.
2, the transformer insulate
For communicate the way of delivering of signal general use transformer insulation interference signal.Insulate transformer is also an in common use insulation parts, use to stop to communicate the direct current interference in the signal and repress the strength of low frequency interference signal.Show transformer Ou to match to insulate electric circuit such as the figure 7-6 bs.Insulate the transformer is opened various emulation load and the number signal source insulation, is also break the emulation ground and the number ground to open.Deliver signal to acquire thoroughfare through a transformer, but the total mold interference is repressed because of doing not form a back track.
Such as figure 7-7 show to 1 kind to take many insulations transformers that the layer shields.When imply the exchanges signal of direct current or low frequency interference carries an importation from a side, according to the transformer principle, two side output's signals filtered out direct current interference, and the low frequency interference signal value also drive consumedly the Shuai reduce and come to a the purpose of repressing the interference thus.Establish static electricity insulation outside a side and two side coils of transformer moreover layer S1 and S2, its purpose is to prevent°from once and two times the mutual Ou that rounds an of set match interference.The 3 F out of the transformer shields to seal completely a body of inside the outside 2 F is used iron, there is the function that the Ci shields, in the center use a copper, connect with iron heart and directly connect ground, there is static electricity shielding a function.These 3 Fs shield layer for keeping outside electromagnetism field from passing transformer the interference is to the electric circuit formation, this kind of insulates transformer to have very strong anti- interference ability.
3, insulate after the electric appliances
After electric appliances coil and touch to order to only have a machine a top formation contact, but have no the contact of direct electricity, therefore can make use of to accept telecommunication, but make use of it to touch some control and deliver telecommunication after the electric appliances coil, can carry out the insulation of strong electricity and weak electricity thus.(such as figure 7-8)At the same time, touch to order after the electric appliances more, and it touches to order to bear bigger load electric current, consequently application very extensive.
Figure more than 7-7 level insulation transformers
Figure 7-8 insulate after the electric appliances
In the actual use, after the electric appliances insulation point suitable for switch quantity delivering of signal.In the system control, in common use weak electricity switch signal the control make to get an electric shock to shut to match and break to open after the electric appliances after the electric appliances coil.But then used for some signals that deliver a strong electricity back track towards shoulding touch a point at the coil, .The insulation is used of is mainly a generally small scaled electromagnetism after the electric appliances after the electric appliances or the stem Huang after the electric appliances.
Three, filter wave
Filtering the wave is a kind of important method that represses interference conduction.Because the interference source sends out of the frequency chart of electromagnetism interference usually compare the frequency chart breadth of signal he/she wants to receive many, therefore, while accepting a machine to receive useful signal, will also receive those don't hope some interferences.At this time, can adopt the method of filtering the wave, the frequency composition needed for letting passes, but interference frequency the composition take into to repress.
The in common use filter can is divided into a low, Gao Tong, take and take filters like Zu,etc again according to its frequency characteristic.Low filter lets the low frequency composition pass, but is higher than to close the composition of frequency to be repressed then, the Shuai reduce, don't let to pass.Gao Tong filter passes Gao repeatedly composition, but is lower than to close the composition of frequency then is repressed, the Shuai reduce, don't let to pass.Bandpass filter lets some on repeatedly taking the frequency composition in the scope to pass, but is lower than next close and is higher than the composition that up closes frequency all is repressed, don't let to pass.Take a Zu filter repress is some inside one frequency scope of frequency composition, make it not pass, but is lower than next close and is higher than the frequency composition that up closes frequency then can pass.
Give or get an electric shock integral whole to turn system in the machine in, the in common use low filter represses from communicate Gao that the charged barbed wire net invades repeatedly interference.Figure 7-9 show the connecting of low filter line diagram of a kind of LC that adopts for calculator the power.Imply moment Gao repeatedly the 220 V of the interference work repeatedly the power pass to close the frequency as the filter with 50 Hzs, , its tall repeatedly the signal be reduced by the Shuai, only the work with 50 Hzs repeatedly the signal arrive power transformer through a filter and promise normal power supply.
Figure 7-9 low filter
Figure 7-10 show electric circuit in, the 7-10 as shows to tremble to repress electric circuit for touching a point, for repress every variety to touch the point or switch is shutting to match or break to open a moment to tremble the interference aroused because of touching point is very effective.The figure 7-10 bs' showing electric circuit is exchanges the signal repress electric circuit, mainly for repressing an inductance load at cut off the power moment the anti- electricity produced power.This kind of Zu permits to absorb electric circuit, can the ability that the magnetic field of inductance coil release, convert into the energy storage of capacitor electric field to get up, the dissipation speed of the since mentally retarded quantity.The figure 7-10 cs' showing electric circuit is the Zu that inputs signal to permit to filter an electric circuit.The circuit that is similar, since as the importation filter of direct current the power, may also is the Zu that imitates electric circuit importation signal to permit a filter.
Figure 7-10 interferences filter an electric circuit
Figure 7-10 interferences filter an electric circuit
Such as figure 7-11 show to take a Zu filter for a kind of pair T types, can use to get rid of work repeatedly(the power) a string mold interference.Input in the diagram the signal U1 to send to output to carry after two thoroughfares.When signal frequency is lower, the C1, C2 is as bigger as C3 resistanceses, the signal mainly delivers to exportation to carry through a R1, R2, when signal frequency is higher, the C1, C2 and C3 permit an anti- very small, approach short circuit, so the signal mainly delivers to exportation to carry through a C1, C2.As long as the parameter chooses properly, can make filter at some inside frequency f 0:00, from the C1, C2 and R3, pay road to deliver to the exportation carries of the signal U2', with from the R1, R2 and C3 road delivers to the exportation carries of signal U"2 size equal, mutually is contrary, cancel out each other, hence always output to zero.F 0 flap frequency for the Xie of double T filter.When the parameter designs, make f 0=50 Hzs, the double T type take a Zu filter and then can filter in addition to work repeatedly interference signal.
Figure 7-11 pairs of T types take a Zu filter
Four, connect ground
Electric circuit, and equipments machine hull...etc. and as the conjunction that carries out low resistance of a public reference point(the earth) of zero electric potentials, call of calling and connecting ground.The purpose that connects ground has 2:One for the sake of the safety, for example connect machine hull, and machine...etc. and the earth of electronics equipments, while existing electric leakage in the equipments, unlikely influence Human body safety, be called a safety to connect ground;Two for providing a basis electric potential for system, for example zero electric potentials of pulse number electric circuit order etc., or for repressing interference, if shield to connect a ground of etc..Be called a work to connect ground.The work connects ground to include to connect ground and order to connect ground two kinds of methods more at 1:00.
Connect ground at 1, 1:00
Such as figure 7-1 show to connect ground at 1:00 for establishing, because of ground electric resistance r 1, r 2 and r 3, establish, so the interference happens to each electric circuit mutually, although this kind of connects a place type very not reasonable, because of more simple, the place using is still a lot of.When the electricity of each electric circuit isn't and greatly even to differ can also force an use;But when the electricity of each electric circuit is very greatly even to differ can not use, because Gao Dian Ping will produce very big ground of electric current to combine interference to the low electricity to go in the even electric circuit.While using this kind of to establish to connect a place type at 1:00 should also notice to put low electricity even electric circuit is being apart from to connect a location's recent place, namely figure 7-1 in Be approached to the AN of ground electric potential to order most up.
Figure 7-12 merge to connect ground at 1:00
Such as figure 7-12 show is merge to connect a place type at 1:00.This way is in the low frequency is is the most suitable to use, because ground electric potential of each electric circuit is as relevant as the electric current and ground line resistance of the ground of this electric circuit, can't because ground electric current but arouse Ou between each electric circuit's matching.The weakness of this way BE, need to connect a lot of ground lines, use more troublesome.
2, order to connect ground more
Order to connect more ground needs a ground of line more, generally be applicable to low frequency signal.If the electric circuit works the frequency is higher, the inductance weight is big, line in everyplace of with each other feeling Ou's matching will increase interference.Such as figure 7-13 show, each connect a location to connect to connect ground to remit to flow row or metals, such as base and outer shell...etc. to reach a piece nearby up.
Figure 7-13 order to connect ground more
3, the design of ground line
The machine electricity integral whole wanted to synthesize to consider variously setting up of line and connected a place method while turning a system design.Such as figure 7-14 show is a set number controls tool machine of connect a place method.Can see from the diagram, connect a ground of system to form three passages:The signal connects a ground of passage and is high the signal, intelligent degree of all small signals, logic electric circuit of connecting of signal the locations all receive signal ground passage up;The power connects a ground of passage and takes care of all big electric currents, big power parts and crystal Zha and all receive this after connecting of electric appliances, indicator, strong electricity part locations on-line;The machine connects a ground of passage and connect tool machines, such as machine cabinet, base, front-panel, fan outer shell and electric motor base...etc. the locations all receive this on-line, the this place line calls again the line passage is safely.Receive these three passages again always public connect in the location, public connect a location to contact the earth good, generally request a ground of electric resistance to be smaller than 4~7.And number control to have enough thick protection to connect a ground of electric cable between strong electricity cabinet and cabinet, if cut the area as 5.5~14 mms 2 of connect a ground of electric cable.Therefore, this kind of ground of line connects a method to have stronger anti- interference ability, can promise that the number controls the normal movement of tool machine.
Figure 7-14 numbers control connecting of tool machine ground
Five, the software anti- interference design
1, the software filter wave
Identifies useful signal and interference signal with the software, and filter in addition to the method of interference signal, be called software to filter wave.Identify the principle of signal to have 2 kinds:
(1)If the time principle controled useful signal and interference signal in time up appear of regulation, can be receiving the time zone of useful signal to open an importation, but is maying appear the time zone of interference signal to close an importation on the program design, filter out interference signal thus.
(2)The space principle is on the program design for promise the signal exactitude that receive without any error, can will never together position, use a different examination method and Be carried on a comparison by the different route or the different importation the same signal for receiving, relate to according to the decided logic to judge really false, filter out interference signal thus.
(3)The attribute principle useful signal is usually the signal in certain value or frequency scope, the software can pass to identify to pick and get rid of while being the signal receiving to keep off the signal's area.
2, the software"trap"
Seeing from the movement of software, the interference of the electromagnetism may make CPU deviate reserved procedure to point needle and get into the RAM area and ROM area that didn't use and arouse some puzzling phenomena in a moment, among them die circulating and the procedure"flying" is familiar.For availably expeling this kind of interference to break down, in common use software"trap method".The basic instruction thought of this method BE, the unit that the system didn't use in the saving machine(RAM and ROM) is used a certain re- start of the code instruction fill with, as the software"trap" to succeed in catching the procedure of "fly".Is general when when CPU carries out the instruction the procedure automatically turns to a certain beginning for starting an address, but starting an address together from this and deposits a hot start procedure that makes the procedure resumes circulate, the hot start procedure scanning the spot of various status, and according to these status judgment the procedure should turn to the system procedure of which entrance, make the system re- throw in normal movement.
3, the software"watchdog"
"Watchdog"(WATCHDOG) is in fixed time the way used hardware(or software) to request to use supervision the machine in fixed time checks a certain procedure or connects and be exceed when the certain time system didn't check this procedure or connect can affirm the system movement comes amiss(interference occurrence), can carry on system to reset through a software or press in advance schedule to way movement."Watchdog" is widespreadly industry to control machine adoptive of a kind of software anti- interference measure.When invade of the sharp Feng electromagnetism interference make the calculator"fly procedure", WATCHDOG can help a system auto instauration is normal to circulate.
Section 3 raises the measure of the system anti- interference
From whole and logic circuit's designing to up raise a machine electricity integral whole to turn the anti- interference ability of product is the instruction thought of overall design, to the credibility and anti- interference function relation that raises system is biggest.For a lately- designed system, if is an important problem anti- interference function to consider, then after system throws in to circulate, the anti- interference ability is strong.Whereas, if wait until the equipments to the spot discovers that the problem just comes to fix a repair to repair, usually meeting matter doubly achievement half.Therefore, at the total design stage, having a few aspects has to arouse a special value.
A, the logic design try hard for simple credibility
Turn a product to concrete machine electricity integral whole, while satisfying the premise of producing the craft control request, logic design should as far as possible simple, in order to economical component, convenience operation.Because in the dollar under the premise that the spare part quality has been already settled, whole in the dollar used spare part amount is little more, the system appears to break down all rate during the period of working small more, that is the stability of system is high more.But remarkable BE, for a concrete circuit, have to extend the stability of circuit amount of storage, stay to have a certain load to permit a degree.Because the work status of circuit is with the size of factors, such as the power electric voltage, temperature and load...etc. but change.When these factors is pledged love condition by the sum to depravation circuit function direction variety, finally cause circuit not ability normal work, this scope is called to stabilize a storage quantity.Work in the circuit or component of edge status in addition, accept outside interference but cause breakdown most easily.Therefore, for improving taking of circuit load ability, should consider staying a load to permit a degree.The load ability of electric circuit in integration door in for example a TTL is the logic door that can take 8 or so the same kind types, but while designing, the generally most consideration takes 5-6 doors, in order to stay a certain Yu degree.
Two, hardware from the examination and the software from restored design
Because the interference arouses of mistake action mostly eventuality of, therefore should adopt a certain measure, make the mistake action of this kind of occasional unlikely and directly influence the movement of system.Therefore, have to try to make on the total design the breakdown that the interference results in can against time resume as usual.Usual way BE, establish the some auto monitor electric circuit on the hardware.This mainly for strengthening supervision to some weak links, in order to narrow to break down scope, strengthen whole credibility.The in common use supervision and the mistake acts to check a method to usually have a data on the hardware deliver of strange accidentally examination(such as importation the electric circuit importation concerning code is accidentally strange the schools check), save a machine of strange accidentally the school check and operate electric circuit, translate the relevant schools of code electric circuit and cycle time electric circuit to check...etc..
Seeing from the movement of software, the interference of the electromagnetism will influence in a moment:The heap inn points the contents that the needle SP, data area or procedure count a machine and makes CPU deviate reserved procedure to point needle and gets into the RAM area and ROM area that didn't use and arouse some if crash, the dead phenomena, such as circulation and procedure"fly"...etc., therefore, the reasonable establishes the software"trap" and"watchdog" and is examining link to carry on a number to filter wave(is like bulky error margin processing) etc..
Three, adopt from the gearing and craft etc. measure to get rid of interference
1, reasonable choose to connect a ground of many machines an electricity the integral whole turns a product, it is all more perfect to thought from the design concrete electric circuit principle.But is working on the scene usually can not work as usual, expose one many because the craft installs the problem that the absurdity brings, it makes thus the system easily accept interference, to this, have to arouse enough value.Such as choice exactitude of connect type aspect in the place to consider communicating to connect location and direct current to connect a location to separate;Promise the logic ground floats empty;(is logic ground and of the earth that accuses to make device need not conductor conjunction)Assurance makes the safely connecting of the fuselage, machine cabinet amount of geology;Even separate to imitate connecting of the connecting of electric circuit ground and number electric circuit a ground of etc..
2, reasonable choice the power reasonable choose the power to the anti- interference of system is also to the pass is important.The power is the important source that ushers in external interference.Practice a proof, through the power lead go into of interference Zao voice is many paths of, such as the control equip win each kind of switch of multifarious shut to match or break to open, the moment of each kind of inductance coil(include electrical engineering, after the electric appliances, get in touch with machine and electromagnetism valve etc.) breaks, the crystal Zha takes care of the power and Gao repeatedly, Medium-frequency Power Supply etc. in the middle of the system leading of switch spare part and close etc.s will arouse interference, these values can reach moment thousand Fu classes, and occupy very wide frequency.Want to completely repress the interference that the such broadband takes scope obviously, have to adopt measure at the same time to the AC power and direct current the power.
A great deal of fulfillment expresses that adoption's pressing quick electric resistance and low filter can make the frequency scope is in the 20 khzs~the interference of with 100 Mhzs consumedly the Shuai reduce.The adoption insulates shielding of transformer and power transformer the layer can get rid of 20 kHz following interference, but for the sake of cancellation exchanges the charged barbed wire net electric voltage slowness variety to control the system result in of influence, can adopt to communicate steady press to wait measure.
Usually need to consider to direct current the power enlarging the power power to permit limit and electric voltage to adjust scope as far as possible.Interference for making the material able to adapt to a load in bigger scope variety and prevent°froming resulting in through the power an internal Zao voice, the whole machine the power has to stay bigger amount of storage, also better dynamic state characteristic.Customarily and generally select by examinations 0.5~100% remaining quantities.Adopt direct current as far as possible moreover steady press the power.The direct current is steady pressing the power not only can repress to come from further communicate charged barbed wire net of interference, and can also repress because of loading variety result in of the electric circuit direct current work the motion of electric voltage.
3, reasonable layout
To machine electricity the integral whole turn each part of equipments and system to carry on reasonable layout, can availably prevent°from the harm of electromagnetism interference.The basic principle of reasonable layout is to make interference source and interference object keep off possibly, the input and output port carefully separates, Gao Dian Ping's electric cable and pulse fuse and low electricity the even electric cable spread to establish etc. respectively.
Also exist a reasonable layout problem to the of each equipments of business enterprise environment.The interference type, interference strength of different equipments to environment is different, the anti- interference ability is also different from the accuracy, therefore, at equipments position decoration up want to consider equipments classification and environment processing, such as nicety's examining instrument should place in the constant temperature environment, and keep off the place of having the machine impact, the weak electricity instrument should consider the electromagnetism interference of work environment strength etc..
Generally speaking, in addition to above-mentioned project, return should at install, cloth line etc. adopt strict craft measure, such as cloth on-line notice the whole system to lead a linear classification of decoration, connect a plug-in of dependable install with good contact, attention weld quality etc..Practice enunciation, for a concrete system, if the craft measure can not only consumedly improve the credibility and anti- interference ability of system, but also also make up the not enough place of some designs properly.