The PLC IO module describes

Interface PLC and the electrical circuit is output through the input section (IO) completed. plc IO module integrates the PLC IO circuit, the input registers reflect the state of the input signal, output point to reflect the state of the output latch. The input module signals into the electrical signals into digital PLC system, the opposite output module. IO into digital input (DI), switching output (DO), the analog input (AI), analog output module. Modular PLC including the cpu module, I / O modules, memory, power supply modules, backplane or rack, these modules can be configured according to certain rules of combination.

Function output module

Programmable Output Module connected to the bus loop controller can be installed in the vicinity of the control device can also be installed in the floor inside the terminal module. Electronic writing code, you can live encoding. analog output module output control logic can be completed according to project conditions Ji programming. When the controller receives the alarm signal to the detector, based on pre-programmed into the program, the controller by bus linkage control signal to the output module, the output module startup requires the linkage of fire-fighting equipment; equipment operation after receiving a signal will be answered.

output module plc, which has several outputs in the form of general

Common plc output module, which has several outputs in the form of general PLC switch output interfaces commonly used by the output of the switching device, there are three different types: output module plc is a relay output, transistor output and bidirectional thyristor output, output module plc. PLC relay output is to use the relay contacts and coils internal  plc sequence of events recording module circuitry with an external load circuit is electrically isolated from the PLC. Transistor output type PLC via opto-coupler transistor is turned off or turned on allows to control an external load circuit, while PLC internal circuit and transistor output circuit is electrically isolated. Relay outputs can drive AC or DC loads, but the long response time, low operating frequency, but the load capacity of the strongest; while the response speed of the transistor output and bidirectional thyristor output interface, high plc input module  operating frequency, but the former can only be used to drive DC load, which can only be used for AC load. Digital output generally two types: type transistors, relays sex. Analog output generally two kinds: voltage, current type.

How to handle input module plc plc signal

PLC analog input module to analog ( continuous signal ) is converted to digital ( discrete signal ) usually after : sampling and quantization two processes. For example, "analog" is the distance from the PLC Programmable industrial controller plc origin of moving objects , " sampling " is equivalent with a camera shooting, at regular intervals on the " capture " a picture , as long as a suitable interval , the picture is also through these intermittent energy about the trajectory of the object. " Quantify " the process is to put these photos in various locations of objects are classified into a limited number of specified location , such as 1 meter , five meters , 10 meters ..... , namely the continuous position data . " format " ( converted to CPU can recognize and handle data format ) , to facilitate the next step of CPU processing . Siemens S7-300PLC for example , 0-20mA input corresponds to 0-27648 , namely PLC internal " 1" represents (20/27648) mA; corresponds to the input of  PLC Power supply module plc 5mA, internal PLC is represented by 6912 .
After the analog to digital conversion , the PLC can be carried out in a variety of digital processing ( including math, logic operation ) , according to the practical application of specific processes identified . For example , determining a first analog input channels of digital value is greater than 6912 ( corresponding to 5mA), meet the conditions , the output of a switch or a digital computing . If necessary you can also go through the digital analog output module ( inverse process) an analog output .

History of PLC

In the industrial production process, a lot of switching sequence control, which in accordance with theplc programmable intelligent controller conditions of the order to move a logical and controlled chain protection action in accordance with the logic of relations, and a large number of discrete data collection. Traditionally, these functions are controlled by pneumatic or electrical system to achieve. 1968 American GM (General Motors) companies to replace the electrical control device, following the requirements of the second year, the United States developed a digital control device company based integrated circuits and electronic technology, for the first time using procedural means used in electrical control, which is the first generation of high speed counter plc, said the Plc high speed counting modules Programmable Controller (PC). After a personal computer (referred to as PC) to develop, in order to facilitate, but also to reflect the high speed counter plc's features, programmable logic controller named Programmable Logic Controller (PLC), and now, still often referred PLC PC.

Role of input and output modules

Fire alarm, the alarm controller output module plc needs to start linkage external control devices such as smoke control valve, sending valve, fire shutter doors, fans, alarm, etc., and to accept the action device answer.
Output modules connected to the bus loop controller can be installed in the vicinity of the control device can also be installed in the floor inside the terminal block. Electronic writing code, you can live encoding. Ji-output control logic output modules can be completed according to the project situation programming. When the controller receives the alarm signal to the detector, based on pre-programmed into the program, the controller will be linked via the bus control signal to theplc analog output module, the output module needs to start linkage firefighting equipment; action after the device will accept a signal answer.

PLC single input-output module features:

1, two bus polarity.
2, the power cord, there is polarity.
3, accounting for two consecutive address points, using electronic encoding encoding.
4, each two monochromatic PLC show the input and plc output module operation information.
5, enter the linkage equipment operation after two feedback signals.
6, dual voltage output signal.
7, the power line power, the feedback input line circuit, the input line open or short circuit, the module returns fault signal.
8, has a line fault detection options.
9, the module output can be set to pulse output or level plc module, appearances default level output.
10, can be connected with an output module  output a set of normally open and normally closed output one active node or 24V voltage signal (to increase the output current).

input module, also known as the control module

input module, also known as the control module, when the output signal can control requirements, or to provide a switching signal to the controlled device movements, and can receive feedback signal device to the host to report to the fire alarm system is an important linkage part of the plc input module and output modules on the market can provide a pair of passive normally open / normally closed contacts for controlling the controlled device, some manufacturers of analog input module can be set via the parameter set corresponding to the active output there are pairs of input and output modules, multiple input and output modules, and so on.

output module plc 's product positioning and product characteristics

Use output module plc saving can be considered to contribute to the cause of environmental protection ! Now the market needs the power module also needs to pay attention to it from the environment.
    Switch output module plc products for the  industrial automation plc point system to contribute to a low-carbon society , and now the market demand began to increase , and it requires a smaller size, lighter weight and higher efficiency and less power consumption , lower output power and no-load conditions . In such a market demand , the development of compact, light weight, high efficiency power supply open frame peak power capability . They offer a wide operating temperature range , to ensure that poor working conditions , excellent output level , smaller size and lighter weight of up to 30% compared to existing models , safe operation. Thus, they can make products smaller customers and help develop energy-saving products . In addition , the plc temperature control module  existing lineup with a wide range of input power factor and harmonic correction helps to reduce energy consumption by a significant reduction in energy-saving equipment size and weight that the product positioning of the power module and product characteristics , the more fully explain the power modules it.if the power supply in harsh environmental conditions , the output DC voltage plus the output transient voltage after the noise is still able to maintain a stable the output voltage does not exceed plc input output modules  the limits of the output voltage level of the situation , otherwise may cause the supply voltage exceeds or falls below a logic circuit ( such as TTL circuits ) is exposed to the power supply voltage malfunction, causing further freezing.

What input module plc automatic control system

input module plc is equivalent to the machine 's brain , we compiled the program is equivalent to the knowledge of people hold grip and rules .
The machine equivalent to the human body, used to  pulse input module plc perform various operations of the PLC .
Electricity, gas, liquid, etc. is equivalent to human muscle and nerve , PLC issued a directive by electricity, gas, liquid , such as the energy to the machine , the machine will perform .
The external sensor feedback to PLC, equivalent to the human eye , nose , etc., will be back to things outside the brain .
That is to take a person or animal analogy , PLC is the brain , PLC combined with the machine equivalent combination of the  Programmable Output Module human brain with the body , but inside the human brain is much more complex process than the PLC , but the people sensitivity and accuracy of the brain is not as PLC. PLC application in China is growing very rapidly. With the rapid development and continuous improvement of basic automation level of China's economy over the next period of time PLC in China will maintain high growth momentum.
When applied to generic PLC equipment can think of it is an embedded controller, but relatively general embedded controller plc IO module  and PLC side has higher reliability and better stability. Some users had encountered in practical work with embedded controllers , is now being gradually replaced by embedded controllers PLC with generic or customized PLC.

PLC controller works

Although the ladder program used by many PLC often use such as relays, timers and counters name, but not the internal PLC entities have the hardware , but in the memory and logic control programs do programmatically edit and output elements borrowed from the connect an external china industrial automation plc entity controlled mechanical device to do . So can greatly reduce the space required for hardware controllers . PLC ladder program execution actually works is the first progressive ladder code to scan and read into the CPU and finally perform control operations. Throughout the scanning process includes three steps , "Input status check ", " run " , "Output status updates " as follows:Step one " input status check ": PLC First check the status of each point switch or sensor inputs connected components of ( 1 or 0 for on or off ) , and its status is written in the corresponding memory location Xn. Step two " running " : progressive ladder program will take into the CPU operation , if the program is running you need to enter the contact state , CPU direct inquiries removed from memory. Operation result is stored in the output coil plc analog output modulesmemory location corresponding to withhold response to the output Yn. Step Three "Output status update " : the step two of the output status update to the PLC output unit contacts , and return to step one . This third step is called the PLC scan cycle , and the time required to complete the PLC called the reaction time ,the time of the PLC input signal if the reaction time is less than this , there is the possibility of misreading . After each run the next time the program before execution , output and input status will be updated once, so this mode of operation as an output , said input of " the end of the regeneration program ."

output module plc in control system

Programmable controller (Programmable Logic Controller) referred to a PLC or PC, is developed from the early relay logic control system, which constantly absorbing micro- computer technology to  Nanda analog output plc continuously enhance the functionality gradually suitable for complex control tasks.
 PLC viable reason is that it is more suitable for industrial field and market requirements : high reliability , simple and strong anti- interference of various programming installation, low price and long life. Than the microcontroller, its input and output ports closer to the field devices , without adding too much of the middle part or need more interfaces , so saving the plc input output modules  user time and cost. PLC lower end (input side ) of the relay , a transistor and thyristor control means for the user while the upper end is usually a microcomputer . When people use it , you can not carry out specialized training in computers , programmable controllers can be operated and programmed. Used to perform a variety of different levels of complexity of industrial control tasks. It began with a wire connected to it subtly with switching devices constitute or use different logic control sequence control . So far, the PLC programming languages ​​- Ladder can also see the shadow of the wiring . Until the late 1960s , early 1970s, the advent of the programmable controller , with the rapid development of microelectronics technology, computer technology and data communications technology, and the emergence of the  plc soe module microprocessor , PLC products towards small and ultra- miniaturization conducted a leap , and finally to the early PLC from the initial logic control, sequence control , PLC has developed into a modern logic, timing, counting , memory and arithmetic operations , data processing, communications and networking functions such as PID loop controller .