Reasonable design PLC controls a system to need contented point

In modern industrial production facilities, have many digital amount and the control equipment that imitate measures, for example of electric machinery case stop, of electromagnetism a powerful person shut, the computation of the product, the set of temperature, pressure, discharge and control, these automata problems in industrial spot, can make up Cheng controller (PLC) already made one of the most effective tools that solve. When the system is designed, PLC control should notice the following. One, but program controller (PLC) reach process designing implement the choose and buy is current the PLC product on the market is numerous, remove shop sign of home made product beyond, foreign brand has: Below Japanese OMRON, MITSUBISHI, FUJI, IDEC, HITACHI, pine, german Xi Menzi, the LG of Korea, how Where is product of PLC of choose and buy? 1. The system should decide the system uses PLC to stand-alone is controlled or use PLC to form a network above all, calculate from this input, output (I ／ O) check the number, the obligate on the base that and should be in when PLC of choose and buy needs check the number actually the surplus of 10 ％ . 2. Affirmatory and laden type carries place to take load according to PLC output is straight flow pattern or communication model, it is big electric current or small electric current, and the frequency that PLC outputs bit of movement, decide output end uses relay to output or transistor is outputted thereby, or it is output of brilliant brake canal. It is very important that different load chooses different output kind to move to systematic stability. 3. The executive speed of executive speed memory capacity and instruction is the main index of PLC type selecting, general storage capacity exceeds big, rate quicker PLC price is higher, although product of foreign each manufacturer is general identical, but also have certain distinction. 4. The PLC product with the different option that ＂ COM ＂ chooses, the quantity that ＂ of its ＂ COM orders is different, dots of some ＂ of COM of a ＂ take 8 output place, some belts output a dot 4 times, also have take 1 or 2 output dot. The sort when load is much and when electric current is big, use dot of ＂ of COM of a ＂ to take 1 - 2 products that export a dot, when laden sort minority measures a long time, use dot of ＂ of COM of a ＂ to take 4 - 8 output select a product. 5. Reasonable the development software that because each produce manufacturer,chooses PLC product is different, systematically compatibility also is the key when the choose and buy, had not discovered completely compatible product at present, should according to the system reasonable choose PLC product. 6. Process designing implement process designing of PLC of choose and buy can take 3 kinds of kind: It is to use general hand-held process designing implement, the statement that it can provide with manufacturer only expresses medium statement process designing. In the middle of means easily the spot is debugged and bulk small cost is low, but its efficiency is low get used to machine sort model little, apply to systematic capacity quite in the system with small, little dosage. 2 it is graphical process designing implement process designing, this kind of means uses graphical means process designing, convenient and intuitionistic, general and electric personnel is short-term can apply freely, but process designing implement the price is higher. 3 it is to use IBM to reach its software of PLC of compatible PC ＋ wraps process designing, this kind of means is a kind of means with highest efficiency, also be a kind of the most commonly used means, but price of major software package is high. 7. The product that chooses big company as far as possible produces quality quantity to have safeguard because of its, and the technology has supported, average after service is better also, after be helpful for of the product patulous upgrade with soft, hardware. 2, the input, design that outputs loop 1. Power supply of PLC of power source loop is AC85 commonly - 240V (also have DC24V) , get used to power source limits wider, but for interference rejection, should add outfit power source to purify component (like power source filter, 1: 1 segregation transformer) 2. The use of power source of the DC24V on PLC has DC24V power supply commonly on product of each company PLC, but size of this power source is small, come for a few milliampere hundreds of milliampere, the size should note when taking load with its, had done at the same time defend short circuit measure (the overload because of this power source or short circuit run those who affect PLC) . 3. If exterior DC24V power source inputs loop to have the immediateness of DC24V power supply switch, photoelectricity switch, and when the capacity of DC24V power source on PLC is insufficient, should from exterior provide DC24V power source; But one ＂ and ＂ COM ＂ carry the ＂ that one ＂ carries the ＂ of this power source not to want the DC24V power source with PLC be linked together, meet those who affect PLC move otherwise. 4. The sensitivity of the input produces manufacturer to have a regulation to the input voltage of PLC and electric current each, the electric current of the biggest input that is more than PLC when the input electric current that inputs component or when having leakage current, can have misoperation, reduce sensitivity. Answer to applicable weak electric current is inputted and adopt preventive measure to leakage current so, and choose an input be the PLC that offers leakage input. 5. Laden to sensibility processing is when sensibility of termination of input, output is laden, should in load a concussion restrains two upright paralell connection implement or diode, the cathode of diode and voltage join of ㈩ pole side. 6. Lock of exterior each other and ground connection benefit control electric machinery positive and negative to turn with PLC etc, when reverse action, cause accident and mechanical damage to avoid the unusual action of PC, should be in exterior composition interlinks loop. Ground connection: GR terminal is earth earthing terminal. With prevent faradic special ground wire (the electrical wiring of above of cut area 2mm2) use means of the 3rd kind of ground connection (ground connection resistor 100 Ω are the following) . LG is terminal of noise filter neutral, because noise is big,be like and produce misoperation, or to prevent electrical shock, receive LG with GR weak point, use means of the 3rd kind of ground connection. The length of ground wire is in 20m less than is advisable. Ground wire and other equipment common or can be just the opposite to what one wished with the metallic structure join of the building, be affected badly. 7. Circuit of PLC exterior drive cannot drive laden circumstance directly to PLC output, must outer ministry uses drive circuit, can use solid state relay or drive of circuit of brilliant brake canal, should use protective circuit and surge to draw circuit at the same time. Additionally the input of PLC outputs wiring to also have particular demand, consult please the operation instruction handbook of each company. 3, of patulous module choose to small system, be like the system of 80 bits of less than, do not need to expand commonly; Become when the system is older, be about to expand. The product of different company, total to the system check the number and patulous module amount have restriction, should expand when still cannot satisfying need, can use network structure. In the meantime, the individual instruction of some manufacturer product does not support patulous module, accordingly, want to notice when undertaking software process designing. When using the imitate module such as temperature, each manufacturer also has a few regulations, consult please relevant technology manual. 4, when the network design of PLC should undertake with PLC the network is designed, its difficulty is gotten greatly than PLC stand-alone control much, should choose oneself to compare familiar type above all, basic to its instruction and functional instruction have more thorough knowledge, and the executive speed of the instruction is mixed user program memory capacity also should understand carefully. Cannot get used to real time requirement otherwise, cause a system to break down. Be opposite additionally communication interface, communication agreement, number sends speed to wait to also want a consideration as it is said. Seek network design and software support and detailed technique data to the manufacturer of PLC even finally, as to choose a few workstation, size of according to system and calm. 5, software work out is before work out software, answer to be familiar with chooses PLC product manual above all, wait for after be familiar with again process designing. If use graphical process designing implement or software wraps process designing, criterion but direct process designing, if use,hold process designing implement process designing, answer to paint echelon picture first, next process designing, can decrease so make mistake, rate is rapid also, make up after finishing, run for nothing first, after it is normal to need each actions, debug on equipment again. CNC Milling