The shallow treads into the PLC control technique and development trend of electrical engineering
1. Say all:
Along with the micro-electronics technique and the calculator technical hair Exhibition, the programmable preface controller has an advance by leaps and bounds of hair Exhibition, its function has already outrun a logic control far and far, in proper order The scope of control, it has an effect to combine with calculator, can enter Go to imitate to control most, have along range correspondence function etc.. Have-The person is called it the modern D industry controls of three pay pillar greatly(namely PLC, robot, CAD/CAM)it a, currently programmable controller BE applied in metallurgy extensively, Mineral industry, machine, light Class D realm, automate for the industry Provided to there is the tool of one dint The PLC controls of tread to open the wreath servo organization into the electrical engineering should Used for combining tool machine to produce an on-line number to control a slippery pedestal to control automatically Make, can the province go to the number of that unit to control system, making that unit The cost of controlling the system lowers.
2、What is a stepper motor:
Stepper motor is a kind of electrical pulses into angular displacement of
the implementing agency. Popular little lesson: When the driver receives a step pulse signal, it will drive a stepper motor to set the direction of rotation at a fixed angle (and the step angle). You can control the number of pulses to control the angular displacement, so as to achieve accurate positioning purposes; the same time you can control the pulse frequency to control the motor rotation speed and acceleration, to achieve speed control purposes.
What kinds of stepper motor sub-:
In three stepper motors: permanent magnet (PM), reactive (VR) and hybrid (HB) permanent magnet stepper usually two-phase, torque, and smaller, step angle of 7.5 degrees or the general 15 degrees; reaction step is generally
three-phase, can achieve high torque output, step angle of 1.5 degrees is generally, but the noise and vibration are large. 80 countries in Europe and America have been eliminated; hybrid stepper is a mix of permanent magnet and reactive advantages. It consists of two phases and the five-phase: two-phase step angle of 1.8 degrees while the general five-phase step angle of 0.72 degrees generally. The most widely used Stepper Motor. What is to keep the torque (HOLDING TORQUE)
3、Tread into the basic characteristics of electrical engineering:
(1)、tread generally into the accuracy of the electrical engineering for tread into Cape of 3-5% and don't accumulate.
(2)、tallest temperatures which enter electrical engineering outward appearance and allow tread and lead into the electrical engineering temperature high can make the magnetism material of electrical engineering back first, cause the dint descend thus is as for lose a step, so the electrical engineering outward appearance allow of the tallest temperature should be decided by small back with electrical engineering magnetism material and order; Speak generally, the magnetism material backs to order all above have in 130 C an of even be up to 200C above, so tread completely normal into the electrical engineering outward appearance temperature in 80-90C.
(3)、dints which enter electrical engineering would with turn to go up but descend soon,While treading to turn to move into the electrical engineering,
electrical engineering each electricity feeling which round a set mutually will become one anti- to electromotive force; The frequency is more high, anti- to electromotive force more big ,big in its function, the electrical engineering enlarges with the frequency(or speed) but mutually the electric current let up, causing the dint descend thus.
(4)、can revolve normally when 4 enter electrical engineering low speed, but if high in certain the speed can't start, and the companion have a roar the interjection tread to have a technique parameter into the electrical engineering: empty carry start frequency, then tread into electrical engineering at empty carry under circumstance can start normally of pulse frequency, if the pulse frequency is high in should be worth., The electrical engineering can't start normally, the possible occurrence throws a step or blocks up to turn. Under the situation that there is one load, the start frequency should be much lower if want to make the electrical engineering attain high speed to turn to move, the pulse frequency should have an acceleration process, then start the frequency is lower, then press certain acceleration to rise the high hoped. Tread to show the characteristics of with it into the electric motor, turn ages of manufacturing to develop important use to accompany with in the numeral small together of numeral turn technical of development and tread into the electrical engineering technical exaltation,tread will get an application in more realms into the electrical engineering.
4、enter an electrical engineering control system to constitute:
Tread is a kind of performance organization that will give or get an electric shock a pulse conversion to move for the Cape into the electrical engineering. When tread to receive to a pulse signal into the actuator, it drives a step to press the direction of enactment to turn to move an angle for fixing to be called "tread to be apart from Cape" into the electrical engineering, it revolves one-step circulate with the fixed angle one step. Can pass control pulse piece to control a Cape to move to attain the purpose of assurance most and thus; Can pass control pulse frequency to control electrical engineering to become dynamic speed and acceleration in the meantime, the purpose attained to adjust thus soon treads into the electrical engineering. Can be the special kind electrical engineering that a kind of control uses, make use of it didn't accumulate error margin accuracy to 100 to divide 100 of characteristics, be suffused with to apply in various open a wreath control PLC which enter electrical engineering technique.
5、Stepper motor of the PLC control technology:
Make the importation tread to be subjected to a homologous control into total amount and pulse frequency of the importation pulse of electrical engineering. Establish the pulse signal occurrence that a pulse total amount and pulse frequency can control a machine therefore and in control,software; Can make use of PL in fixed time a machine composing for the frequency lower control pulse, the pulse frequency can pass in fixed time machine in fixed time constant control pulse period, the pulse amounts control then can establish a the pulse counter C10 be when the pulse number attain initial value, count machine C1.The action cuts off pulse back track, making it stop, the servo organization tread into the electrical engineering have no the pulse input then stop operation, servo performance organization fixed position be servo performance organization of when move speed to have higher request, can use PLC high-speed pulse, Different PLC it the frequency of high-speed pulse can reach to 4000-6000Hzses. The PLC is used to produce control pulse, passing PLC plait distance exportation several pulses certainly the control treads to turn Cape into the electrical engineering, programmable controller output's control the pulse enters electrical engineering to switch on electricity sequence to assign by the step homologous of round a set. The PLC controls of tread can go an allotment machine by adoption software wreath into the electrical engineering, the hardware wreath goes allotment machine to adopt the PLC resources that the soft wreath takes up more, Tread especially to round a set to count mutually into the electrical engineering big should consider adoption hardware wreath to go allotment machine well for large production line at 4, although the hardware structure is a little bit a little more complicated, can save an exportation importation of taking up the PLC point, the market has a various appropriation chips to choose to use currently. Tread to enlarge to several ten highest hundred folds into the output's control of the actuator PLC of the electrical engineering power pulse, volt, several Anne arrive several ten several Anne s drive an ability, the exportation of general PLC connects to have to certainly drive an ability, but inside usual transistor flow exportation to connect an ability only for ten several arrive several ten volts, several ten arrive several 100 million Anne but tread to then have several request into the electrical engineering to the power ten arrive up 100 volts, several Anne arrive several ten Anne s drive an ability so should adopt an actuator to output the pulse carry on enlarging.
6、Application features of PLC
(1)、High reliability, strong anti-interference
High reliability is the key to performance of electrical control equipment. PLC as the use of modern large scale integrated circuit technology, using the strict production process, the internal circuits to the advanced anti-jamming technology, with high reliability. Constitute a control system using PLC, and the same size compared to relay contactor system, electrical wiring and switch contacts have been reduced to hundreds or even thousands of times, fault also greatly reduced. In addition, PLC hardware failures with self-detection, failure alarm timely information. In the application software, application are also incorporated into the peripheral device fault diagnosis procedure, the system is in addition to PLC circuits and devices other than the access protection fault diagnosis. In this way, the whole system extremely high reliability.
(2)、Fully furnished, fully functional, applicability
PLC to today, has formed a series products of various sizes, can be used for occasions of all sizes of industrial control. In addition to processing other than logic, PLC data, most of computing power has improved, can be used for a variety of digital control in the field. A wide variety of functional units in large numbers, so that penetration to the position of PLC control, temperature control, CNC and other industrial control. Enhanced communication capabilities with PLC and human-machine interface technology, using the PLC control system composed of a variety of very easily.
(3)、Easy to learn, well engineering and technical personnel welcome
PLC is facing the industrial and mining enterprises in the industrial equipment. It interfaces easily, programming language easily acceptable for engineering and technical personnel. Ladder language, graphic symbols and expressions and relay circuit very close to are not familiar with electronic circuits, computer principles and assembly language do not understand people who engage in industrial control to open the door.
(4)、System design, the workload is small, easy maintenance, easy to transform
PLC logic with memory logic instead of wiring, greatly reducing the control equipment external wiring, make the control system design and construction of the much shorter period, while routine maintenance is also easier up, even more important is to change the procedures of the same equipment has been changed
production process possible. This is particularly suitable for many varieties, small batch production situations.
7、The development trend of 5 domestic and international electrical engineering: (1)、continue along small scaled direction development turned along with electric motor application the realm open widely and each kind of whole machine is continuously small scaled to turn, the electric motor which requests with its kit have to also more and more small, at 57, the electric motor of 42 machine seat numbers applies many after years, now its machine seat number to 39,35,30,25 directions get down extension.
(2 )、right nesses of electric motors carry on comprehensive design namely turn soon position to spread a feeling machine, decelerate the wheel gear etc. and electric motor essence to synthesize design together, so make it be able to constitute 1 to shut wreath system expediently, as a result have one more superior control function.
(3)、to five mutually with three mutually the electric motor direction develop, Be suffused with currently applied of two mutually with four mutually the electric motor, its vibration and voice are bigger, but five mutually with three mutually the electric motor have advantage but in regard to these two kinds of electric motors, five mutually the electric motor drive electric circuit compare. 8、Conclusion:
At present, the use of programmable process controller (that is, the PLC technology) can easily realize the control of motor speed and the position of the convenient, c onvenient for a variety of stepper motor operation, t o complete a variety of complex work. It represents the advanced industrial automation revolution; accelerate the realization of the electromechanical integration.
应使输入步进电机的输入脉冲总数和脉冲频率受到相应的控制。因此在控制软件上设置一个脉冲总数和脉冲频率可控的脉冲信号发生器;对于频率较低的控制脉冲,可以利用PL的定时器构成,脉冲频率可以通过定时器的定时常数控制脉冲周期,脉冲总数控制则可以设置一脉冲计数器C10当脉冲数达到设定值时,计数器C1。动作切断脉冲发生器回路,使其停止,伺服机构的步进电机无脉冲输入时便停止运转,伺服执行机构定位当伺服执行机构的位移速度要求较高时,可以用PLC的高速脉冲发生器. 不同的PLC其高速脉冲的频率可达4000 6000Hz. PLC用来产生控制脉冲,通过PLC编程输出一定数最的方波脉冲,控制步进电机的转角,可编程控制器输出的控制脉冲按步进电机的通电顺序分配到相应的绕组。PLC控制的步进电机可以以采用软件环行分配器,硬件环行分配器采用软环占用的PLC资源较多,特别是步进电机绕组相数大于四时,对于大