PLC controls a system to devise a method

The main content that the system designs (1) the technical condition that protocol control system designs. Technical condition decides commonly with designing the form of assignment certificate, it is the basis of whole design; (2) choose the actuator such as a powerful person of electric drive form and electromotor, electromagnetism; (3) the model of PLC of make choice of; (4) the input of work out PLC / output allocation is expressed or scale is inputted / output terminal hookup; (5) the requirement that designs according to the system writes software specification book, next the programming language with corresponding reoccupy (commonly used echelon pursues) undertake programming; (6) understand and abide by user acknowledge psychology, take the design of man-machine interface seriously, heighten the affable concern between person and machine; (7) design work station, electric ark and nonstandard electric equipment yuan component; (8) write design manual and operation instruction handbook; According to particular job, afore-mentioned content can be adjusted appropriately. 2.

The basic measure that the system devises can make up Cheng controller to use systematic design and applied main measure. (1) thorough knowledge and the craft condition that analyse object be accusinged and control requirement A.

Object be accusinged is controlled machinery, electric equipment, product line or manufacturing process. B.

The composition that the fundamental pattern that control asks main accusation is made, action that should complete, automatic job circulates, necessary protection and interlocking wait. To more complex control system, still can assign control task into a few independent parts, this kind can be changed numerous for brief, be helpful for process designing and debug. (2) basis of affirmatory I/O equipment is accused the functional demand that the object controls a system to PLC, fix equipment of the user input that systematic place requires, output. Commonly used input sets switch of stock pushbutton, select switch, journey, sensor to wait, commonly used output sets a powerful person of stock relay, contactor, indicator light, electromagnetism to wait. (3) the user I/O equipment that chooses appropriate PLC type basis to already decided, the input signal that statistical place needs and the check the number that export signal, select right PLC kind, the choice of module of the option that includes type, choice of the capacity, choice of I/O module, power source. (4) the input that allocates I/O dot to allocate PLC outputs a dot, the work out gives an input / output allocation is expressed or the picture gives an input / the hookup that outputs terminal. Then 9 can undertake PLC programming, can undertake controlling the design of ark or work station and spot construction at the same time. (5) program of plan of echelon of design application system goes echelon to pursue according to the design such as working function chart or condition flow chart namely process designing. This one pace is design of whole application system most core works, also be more difficult one situation, want to devise good echelon plan, want to be familiar with control requirement very above all, have the practice experience of proper electric design even at the same time. (6) should use order input PLC simple and easy process designing implement when inputting the program PLC, need changes echelon plan into instruction mnemonic first, so that input. Should use but the software of auxiliary process designing of program controller is in on the computer when process designing, the join cable that can leave an opportunity through going up downloads the program to go in PLC. (7) after undertaking software checks a program to input PLC, answer to undertake checking the work first. Because be in programming in the process, hard to avoid can have the place of careless omission. Before because this is in,going up PLC join to spot equipment, indispensible undertake software checks, in order to eliminate the error in the program, also debug dozen of good foundation for whole at the same time, shorten the cycle that whole debugs. (8) applied system whole is debugged after in PLC soft hardware is designed and control ark and spot construction are finished, with respect to the debugging on-line that can have whole system, if control system is,divide composition by a few ministries, should make first local debug, undertake whole is debugged again next; If the pace foreword of control program is more, can undertake section is debugged first, join again next rise to always be moved. The problem that in debugging, discovers, want one by one to eliminate, till debug a success. (9) file of technology of system of staff technology file includes graph of manual, electric principle, electric equipment to arrange plan of echelon of list of graph, electric component, PLC. 3, PLC hardware system is designed 1.

The choice of PLC model is before those who make a system dominate program is decision-making, want the control requirement that understands object be accusinged in detail, decide to whether choose PLC to undertake controlling thereby. In control systematic logic concerns more complex (need relay of many auxiliary relay, time, tally to wait) , more frequent, need undertakes technological process and product remodel data processing and information management (the control that know exactly about sth seizes operation, imitate to measure, PID adjustment) , use PLC control is very necessary. Current, produced manufacturer numerously domestic and internationally to provide a variety of series functions the PLC product of each different, use a dazzling, not know what to do. So overall balance advantages and disadvantages, choose type ability to achieve the goal with practical economy reasonably. General choice type wants to need in order to satisfy systematic function to be a tenet, have an insatiable desire for big demand perfection not blindly, lest create the waste of investment and equipment resource. The choice of type can consider from the following respects. (1) to the input / the choice that outputs a dot chooses the type with much check the number blindly to be able to create certain waste. Want to get the I/O total check the number of cleared control system first, the 20 ％ of 15 ～ that want total check the number by actual place again dosage of put apart equipment (be a system transform etc take superabundant land) hind the check the number that wants PLC certainly. Want to notice additionally, the module that input of a few high density nods inputs check the number to have restriction to what put through at the same time, the input dot that puts through at the same time commonly always must not input the 60 ％ of the dot more than; The drive ability that PLC outputs a dot every (A/ is nodded) also be finite, its output some PLC at every o'clock what voltaic size still increases laden tension along with place is different and different; What the permission of general PLC outputs electric current to follow environmental temperature is elevatory and reduce somewhat etc. Want to consider these issues when type selecting. The output dot of PLC can be divided to choose form in all, in group type and segregation type receive a standard a few kinds. Each groups of output that keep apart type can use different voltage sort and voltage social estate between the dot, but this kind of PLC is average every price of the dot is higher. If do not need to keep apart between output signal, before should choosing two kinds output the PLC of means. (2) can make rough estimation only to user memory capacity to the choice of memory capacity. In having pilot system to switch quantity only, can take 10 words with input total check the number / total check the number of the output that nod ＋ takes 5 words / the point comes estimation; Tally / timer is pressed (3 ～ 5) word / estimation; When operation is handled, press (5 ～ 10) word / quantity estimation; In imitate measures an input / in the system of output, can input by every / (or output) all the way imitate quantity needs about (80 ～ 100) the memory capacity that the word controls comes estimation; Every interface is pressed when the address manages the measure of 200 words above is rough estimation. Finally, the 100 ％ of 50 ～ that press estimation capacity commonly take amount having abundant. To lacking the architect of experience, quantity having abundant stays to want a little bit big when choosing a capacity. (3) the time defer that the chooses PLC I/O that answers time to I/O answers time to include input defer, output circuit defer and scanning work way to cause (scan 3 times in 2 ～ commonly periodic) etc. Measure pilot system to switch, PLC and I/O answer time to be able to satisfy the requirement of actual project commonly, but need not consider I/O to answer a question. But measure pilot system to imitate, especially closed circuit system is about to consider this issue. (4) the output means to PLC has the load that differs according to outputting laden characteristic type selecting to ask accordingly. For example, the sensibility that connects often is laden, should choose transistor or output of brilliant brake canal, and should not choose relay output. But relay is outputted model PLC has a lot of advantages, if guide,connect pressure fall small, have segregation effect, the value is relative cheaper, bear instantaneous overvoltage and the capability that pass electricity are stronger, its load voltage is agile (can communicate, can flow continuously) and voltage grade range is big etc. The movement is not so frequent hand in, dc load can choose relay output PLC. (5) right online leave line process designing to show with the choice of process designing leaving a line point to lead plane and process designing implement common a CPU, pass process designing implement the process designing that means select switch will come to choose PLC, monitoring and moving job status. When process designing condition, CPU is process designing only implement service, and incorrect spot undertakes controlling. Special process designing implement process designing attributes this kind of situation. Online process designing is to point to lead plane and process designing implement each have a CPU, the CPU of lead plane finishs the control to the spot, in fine of each scanning cycle and process designing implement communication, process designing implement issue lead plane modification order, in next scanning cycle lead plane will press new program to undertake controlling to the spot. The computer assists process designing to be able to realize process designing leaving a line already, also can realize online process designing. Online process designing needs to purchase the computer, deploy process designing software. Use method of which kinds of process designing to should decide according to need. (6) according to whether type selecting of couplet net communication if couplet of need of PLC pilot system joins factory automation network, criterion PLC needs to have function of communication couplet net, ask PLC should have link namely other PLC, go up an interface that the computer reachs CRT to wait. Big, medium-sized aircraft has communication function, at present major small-sized opportunity also has communication function. (7) below the case that the choice to PLC configuration orders data in same function and identical I/O, integral type is lower than module type price. But module type has a function patulous and agile, maintenance is convenient (change module) , judge the merit such as breakdown easily, want to choose the configuration of PLC by real need. 2.

Allocate an input / it is one to one correspondence that output nods general input to dot and input signal, output is nodded and export control. After allocating, press the passageway that the system configures and contact date, distribute each input signal and output signal, have number namely. Below individual situation, also two signal input a dot with, before should receiving an input to nod in that way, receive fine line by logistic relation (establish ties first like two contact or shunt-wound) , receive input point again next. (1) range of affirmatory I/O passageway is distinct the PLC of model, its are inputted / the limits that outputs a passageway is different, answer to choose PLC model according to place, consult corresponding process designing manual, anything but but " confuse one thing with another " . Must consult concerned operation manual. (2) the ministry assists relay in-house and auxiliary relay is not outputted external, cannot receive exterior parts of an apparatus one after another continuously, controlling other relay, timer however / the be valid when tally occupies memory or data processing is used. Tell from the function, in-house and auxiliary relay is equivalent to a tradition electronic-controlled the auxiliary relay in ark. The input that did not allocate module / output relay area and did not use 1: The link relay when 1 link all can be used the area as in-house and auxiliary relay. According to the need of programming, should the in-house and auxiliary relay of reasonable arrangement PLC, should list in designing a manual each interior assists relay in detail the utility in the program, avoid to repeat use. Consult concerned operation manual. (3) allocate timer / the timer of tally PLC / tally amount sees concerned operation manual respectively. 4, method of design of PLC software system and measure 1.

The method that PLC software system devises is in after knowing PLC program structure, be about to weave specificly program. The method that weaves PLC controls a process is very much, here basically introduces a few kinds of typical process designing methods. (1) diagram method of diagram method process designing is to rely on draw to undertake PLC programming. Common basically have echelon plan law, logistic flow chart law and pace enter flow chart of law, sequential suitable control a standard. A.

Echelon plan law: Echelon plan law is to use echelon graph language to weave PLC program. This is a kind of process designing method that imitates relay to control a system. Its graph even component name dominates circuit with relay ten split phase are close. This kind of method is very light the ground can control former relay the echelon graph language that circuit transplanting becomes PLC. This to be familiar with relay for pilot person, it is method of the most convenient a kind of process designing. B.

Logistic flow chart law: Logistic flow chart the law is the executive course that represents PLC order with logistic block diagram, reaction inputs the relation with output. Logistic flow chart the technological process that the law is a system, the logistic flow chart that expresses to form a system with logistic block diagram. The PLC that this kind of method weaves controls program logic the requirement of the causal lock that reach couplet of clarity of train of thought, input and output is specific. Logistic flow chart can make whole process sequence of thought clear, facilitating analysis controls a process, facilitate search trouble spot, facilitate debug program and maintenance program. Sometimes complex to program, be expressed with the statement directly and may feel difficult with echelon graph process designing the following hand, can draw logistic flow chart first, each parts that are logistic flow chart again are expressed with the statement and PLC of echelon picture authorized strength uses a program. C.

Sequential flow chart law: Sequential flow chart the sequential chart that the law makes draw control system above all (should undertake to certain time which pilot controls sequential chart namely) , give the program block diagram of corresponding control task according to sequential relationship painting again, write program block diagram into PLC program finally. Sequential flow chart law very the process designing method that agrees with to be standard control system with time. D.

The pace enters suitable control a standard: The pace is entered suitable controlling a standard is to be in arrange those who accuse an instruction to cooperate to issue the control order with complex design. Compare complex program commonly, can divide into a certain number of the block with simpler function, a block can regard as the one pace in whole control process. Go looking from whole point of view, the control process of a complex system is by such a certain number of the pace comprises. Systematic pilot task can think to be engraved when differ or finish the control of each pair of paces in different process actually. For this, many PLC production manufacturer increased a pace to enter in his PLC suitable accuse to dictate. After drawing the condition flow chart that each paces enter, can use a pace to enter suitable accuse an instruction to write control program conveniently. (2) law of experience of experience law process designing is those who apply oneself or the experience of others undertakes designing. Majority is the program with close of him craft requirement chooses first before the design, what these programs regard him as " test program " . Join the case of own project, to these " test program " one by one is revised, the made project that fits oneself asks. The experience that says here, have a plenty of the experience summary that comes from oneself, some likelihoods are the design experience of others, need accumulate over a long period, be good at summing up. (3) CAD of CAD process designing is to pass software of PLC process designing to undertake programming on the computer, leave a line or online process designing, be emulated from the line and online debug etc. Software of use process designing is OK very leave a line on the computer conveniently or online process designing, online debug, software of use process designing is OK very be in what the program has on the computer to access conveniently, add close and form EXE to run a file. 2.

The measure that PLC software system devises is on the foundation that knew program structure and process designing method, be about practically writes PLC program. Write PLC program and like writing other computer program, need to experience following processes. (1) the intent that assigns a cent piece to systematic task is a complex project, decompose many simpler little jobs. Such a complex big question melt into many simple small issues. Can facilitate so work out program. (2) the logistic concern plan of system of work out control pursues from logistic relation on, can react what the result that gives some logic to concern is, this one result England derives what movement. This logistic relation can be with dominating an activity individually order is fiducial, also may be the time metre with whole activity is fiducial. Logistic concern plan reflected action of the control in controlling a process and the activity of object be accusinged, also reacted the relation of input and output. (3) scale all sorts of circuit graph scale the purpose of all sorts of circuit, the input that is a system outputs the address of a design and name connection to rise. This is very crucial one step. When the input of scale PLC, the link that should consider signal not only is nodded whether with name consistent, the voltage that carries considering the input even and electric current are appropriate, also want to consider the issue such as the reliability that runs below special condition and stable condition. Should consider particularly whether the input end that leads maximum pressure to PLC, introduce high pressure PLC inputs end, can cause greater harm to PLC. When the output circuit of scale PLC, the link that should consider output signal not only is nodded whether with name consistent, bring laden ability and proof voltage capacity considering what PLC outputs module even. In addition, consider the output power of power source and polarity issue even. In the scale of whole circuit, the principle that considers a design even raises its stability and dependability hard. Although use PLC,undertake controlling convenient, agile. But still need on the design of circuit careful, comprehensive. Accordingly, want to consider to help somebody attain his aim when scale circuit pursues, where should install pushbutton, where should install switch, want meticulous. (4) hand-in-hand travel imitate debugs program of work out PLC to be over in scale after circuit pursues, program of OK PLC of hand work out. Can use afore-mentioned methodological process designing of course. When process designing, besides should notice the program wants correct, reliable besides, when considering a program to want forthright, province even, facilitate read, facilitate revise. Had made up a program block to want to have imitate test, such facilitating search a question, facilitate revise in time, general ledger had better not calculate together after whole process is finished. (5) the console that make and control ark are over in scale electric equipment, after writing a program, can make console and control cabinet. When time is nervous, this job also can be mixed work out program is paratactic undertake. In the console that make and the quality that the parts of an apparatus such as select switch, pushbutton, relay should note when controlling ark, norms must satisfy a requirement. The installation of equipment must notice safe, reliable. Wait for a problem e.g. segregation of screen problem, ground connection problem, high pressure must appropriate processing. (6) the spot debugs the spot is the important segment that whole control system finishs. The design of any programs very it's hard to say does not debug what can use through the spot. Debug ability to discover control loop and control program cannot satisfy the place that the system asks through the spot only; Debug ability to discover control circuit and control program produce contradictory part through the spot only; Undertake the spot is debugged only ability checks on the spot finally and adjust control circuit and control program finally, with the requirement of adaptive control system. (7) write technical document and after the spot tries moving course spot to debug, control circuit and control program were decided basically, the hardware of whole system and software do not have a problem basically. Be about at this moment file of comprehensive commutate technology, include to arrange program of circuit graph, PLC, service instruction and help file. Come here the job ends basically. CNC Milling