【 Weak current College 】 industrial control computer components and features

Industrial control computer:

Used in industrial control computer known as industrial control computer. Hereinafter referred to as control of the machine. It consists of a computer and process input/output (I/O) through two major components.

The computer is determined by the host, input and output devices, and external drives, tape drives, etc. In the computer an external part added to process input/output channels, used to complete industrial process measurement data into the computer for processing; on the other hand the computer to the production process controlled by the command, information is transformed into industrial control object for the control variable signal, and then sent to the controller of industrial control object. By controller exercise operational control of the production line.

Industrial control computer's features:

Control machine and general computer, has the following characteristics:

(A) has a perfect process channel, to facilitate various forms of information transformation, and complete inspection data input and output control information.

Enter the production process detection signal there are two broad categories: one category is a voltage or current analog signals: the other switch quantity or amount of digital pulses. Switch quantity, pulse volume belongs to the digital signal. Usually detect production process signal is analog, has been a detection signal amplification, the transformed (secondary instrument) into voltage 0 to 10 Volt or 0 to electro-10mA. these analog must die/digital converters (ADC: Analog-DigitalCnverter) into digital content, in order to be accepted by your computer.

Same output control signal is digital, but also have a d/a converters (DAC: Digital-AnalogCnverter), the digital signal to analog signal 0-10 Volt or (0-+ 5 volts) or changes to current: 0-10mA, then fed to the controller to control the production equipment.

Channel number in settings mode/converters (ADC) and d/a converter (DAC) complete analog to digital and digital to analog.

If the detection process status signal is digital content into channels generally use isolation (photovoltaic, transformers, switchgear) digital signal, as long as coupled potential fit, can be the computer accepts.

(Ii) to have a quite complete in system and high speed data channel so that it can quickly respond to the issue of the production process in the request, and can exchange information in real time the production process.

From process input/output channels of the request, in the paragraph into in priority level (some complex systems into 0 … 3-type, three-channel for the process, and put it in section 0 ... 7 level) from the production process of information processing ranked for those site save time short signal, high priority level in order to be processed. Example: measurement of molten steel in the steelmaking process temperature signal, enter the request (request), two seconds it will take the temperature of the thermocouple signal into, and converted to digital content is being fed into the computer, so hurry to handle signals go high speed channel. And to set high in the paragraph level, so that it can in two seconds into the signal from the computer. And if by the large optical spectrometer measured steel components, each of the components (such as Mn, P, S, C, etc.) sent to the computer, the computer accepts the request, qualified computers must be removed within this 330ms, otherwise send the next component. This request will be sent to your computer data the spectrograph in paragraph level height for priority, so does the time take to the access data. The heartbeat from the production process according to solicit-response time to set the priority level. Also be perfect in function guarantee control function.

(Iii) have a high reliability.

Industrial production often continuous (diurnal) production, this requires the control computer with high reliability. No half-way down, you cannot fail. Current computers are obtainable for thousands of hours out of a failure. Is failed due to check the program quite complete can also be repaired within minutes.

In order to enable the controller to prevent outside interference in addition to the power supply system using isolating transformer, the process in the production process and also take isolation between channels, the computer system and external process controller and check there is no common ground between the instruments. Use the following three methods:

(1). Use relay isolation.

(2). Transformer isolation.

(3). By photoelectric isolation.

(Iv) have the man-machine contact function, in order to achieve the man-machine dialogue, in a timely manner to the production process for the necessary intervention. Production process often occur in the event of an accident, or production equipment problems, control failure, you will need to manually stop the computer control, or find control deviation, artificial to revision control.

(5) have correctly reflect the production of mathematical model, the model can only approximate reflect production rules, the less its approximate error, or the approximate extent of the closer, the more easy to achieve optimum control of the production process, increase productivity, improve product quality, reduce consumption and reduce costs. Therefore, the realization of computer-controlled, constant improvement and correction of mathematical model, improve the mathematical model of approximate degree is an indispensable work.

(6) have suitable for control of software systems. Including operating system software and application software to improve quality control, such as suitable for online control of real-time operating systems, various process input/output channels of the interrupt handler that processes the data transfer process I/O error handler and process control applications.

It should be noted that for onsite production process various production equipment must have:

1. Have acceptable control of the machine (input/output channel) information sent by the control, and production equipment to exercise control of the controller or control parts. If a DC motor, often used toControlled Silicon controller, solutions for accepting controller sent control signal control motor starting and stopping and speed. There is a general control instruments (PID meters) from the computer to PID tuning the instrument set or modified by positive values, the given PID instrument for positive exercise control.

2. To test the production equipment of the operational status of a meter (Assembly) or secondary transformation instrument parts. Detection instrument output information can be controlled machine process input/output channels of analog and digital.

3. Be reflected in the production of mathematical model.

This is the realization of computer-controlled production of three prerequisites, only with these three conditions will talk about computer automatic control of the production process.