Defined PLC controller

programmable logic controller initially only circuit logic control function, so named as a programmable logic controller, and later with the continuous development of these original functions have simple computer module including logic control, timing control, analog control , multi-machine communications, and many other features, the name was changed to the plc controller. PLC controller mainly refers to digital computing operation of the electronic system programmable logic controller for controlling the mechanical production process.

How to select plc IO module manufacturers

Domestic production plc IO module manufacturers are said to have many thousands, how can choose their own power supply module manufacturers do?
1, for the size of their own requirements. Some foreign brand quality is really good, but the price is not every user can programmable plc  accept, plc IO module and delivery compared to domestic brands, is very long. For some of the larger domestic supplier of power modules also have this problem, if you set its main ship models of non-models, delivery is also not guaranteed. If you own custom made a special power, for small customers, is simply unthinkable. Because SMEs did not like Huawei, ZTE delivery platform choice, to choose their own scale enterprises, is very important. VST such as power companies, specifically for SMEs to provide power solutions, to provide customized services.
2, plc IO module product line to see the  plc temperature control module situation. Such as power modules, it can provide as a half brick, 1/4 brick, 1/8 brick, 1/16 brick industrial products such as can not provide, explain corporate R & D strength and size is small. The ability to customize the product, whether it can provide a wealth of customized products, customized experience like railways, electricity, military areas or very important. Look material. Open a module power, their own look, workable than listen to others. Material from the supply of products, we can see that the quality of power supply manufacturers and positioning, choice of materials, like the Programmable Input Module  power to see the materials. Open a module power, their own look, workable than listen to others. Material from the supply of products, we can see that the quality of power supply manufacturers and positioning, choice of materials like power

input module plc introduced in the DC chopper

DC / DC converter is a variable DC voltage into a fixed DC voltage , also known as a DC chopper . Chopper work in two ways , first pulse width modulation Ts constant change ton ( GM ), input module plc Second, frequency modulation (
(1) Buck circuit - step-down  intelligent plc chopper , the output average voltage less than the input voltage U0 Ui, of the same polarity .
(2) Boost Circuit - boost chopper , the output voltage U0 is greater than the average input voltage Ui, the same polarity .
(3) Buck-Boost circuit - a buck or boost chopper , the average output voltage is greater or less than the input voltage U0 Ui, of opposite polarity , inductive transmission. 4) Cuk circuit - a buck or boost chopper , the average output voltage is greater or less than the input  programmable logical controllers voltage U0 Ui, of opposite polarity , capacitance of the transmission . There Sepic, Zeta circuits. input module plc above non-isolated DC-DC converter circuit , isolated DC-DC converter circuit has a forward , flyback , half-bridge circuit , full bridge circuit , push-pull circuit .
Soft-switching technology makes plc intelligent controller  today's DC / DC undergone a qualitative leap , the maximum output power 300W, 600W, 800W , etc. , the corresponding power density (6.2,10,17) W/cm3, efficiency ( 80 to 90 ) % . The switching frequency (200 ~ 300) kHz, the power density has reached 27W/cm3.

Selection of low-cost analysis of the input module plc

PLC because of its high reliability , simple programming , versatility , small size, compact structure, convenient installation and maintenance , etc. , and in the industrial control has been widely used . PLC modules are generally divided into the following categories : switch input modules , digital output modules , analog input module , analog output modules. Industrial  plc digital input output module control, especially in the field of process control and control need to collect more than analog , input module plc thus PLC analog input and output modules require more, and analog input and output modules are more expensive, increase the analog input and output modules increases the cost and reduces the cost of the entire system , input module plc limit the application of PLC. This paper presents a communication -based analog input and output modules extension method seeks to solve this problem based  Programmable Input Module on analog communication input, output module extension methods
PLC analog input module 12 extend all the way to where the analog input , for example, in the form of an analog signal standard 0 ~ 5V input voltage signal feeding side, the application 12 A / D conversion chip MAX187 analog- digital conversion. MAX187 is a 12-bit serial A / D, has a high conversion rate , the sampling frequency is 75kHz, suitable for high precision here all the way 12-bit analog output , for example, the design will be  plc intelligent controller using 12 D / A converter chip MAX531 to achieve the number of touch conversion. We MAX531 op amp output termination , the analog output is adjusted to 0 ~ 5V, the output part of the hardware circuit shown in Figure 3 . Here , MAX531 is a 12-bit serial D / A, has a higher conversion rate...

How to design output module plc in three-wire constant current source driver circuit

output module plc due to the temperature of the integrated operational amplifier parameters that affect not as a transistor or FET parameters affect significantly the integrated amplifier composed of a constant current plc communication modules  source with the stability better, more constant performance advantages. In particular, the need to ground at the load end of the occasion, received a wide range of applications. Dual op amp constant current source. UA1 amplifier output module plc which constitute adder, 1) load can be grounded; 2) When the op amp is a dual power supply, the output current is bipolar; 3) constant current size adjusted by changing the input reference datum reference resistor Rref0 size to achieve, it is easy to obtain a stable small current calibration and compensation.
Since the resistance of the mismatch, the  plc power supply module voltage across the reference resistor output module plc Rref0 will affect the load end of the driving voltage Vb. The same time as a constant current source, and will definitely change with load changes, which will affect the stability of the constant current source. Obviously, this high-precision constant current source is unacceptable. So R1, R2, R3, R4 selection principle which four resistors is to try a small mismatch, and every size of resistor mismatch direction to be consistent. In practice, a lot of the same batch can be screened precision resistors, where resistance is close to elect four resistors.

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 .

The role of output modules plc

Fire alarm, the alarm controller output module needs to start by the linkage of external control devices, such as ethernet module plc control valve, sending valve, fire shutter doors, fans, alarm, etc., and to accept the action device to answer.
output module plc connected to the bus loop controller can be installed in the vicinity of the control equipment can also be installed in the plc high-speed counting module inside the terminal module. Electronic writing code, you can live encoding. Ji-output control logic output module 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 procedure, the controller via the bus output control signal to the interlocking modules, output modules linkage needs to start fire-fighting equipment; action after the device receives a reply signal.

IO module, also known as the PLC control module

plc IO module is also called a control module, can be output when the control request signal or a switching signal to plc communication module operation of the controlled device, and may receive a feedback signal from the device to the host to report to the fire alarm system linkage important part of the input and output modules on the market can provide a pair of passive normally open / normally power supply module plc contacts for controlling the controlled device, some manufacturers of modules through parameter setting, set to active output (eg Bay GST-LD-8301), there are also double the corresponding input and output modules, the input and output modules, and so more.

Input Module plc's shortcomings

input module plc Disadvantages: module mechanism to bring safety hazard
1, the intercept system calls.
2, modify the output symbol table.
3, by modifying the system calls the plc temperature module themselves hidden.
4, redirect file operations.
5, modify the file owner.
6, plc controller suppliers processes.
7, the executable file redirection.
8, calling sys_socketcall by modifying the system, making the system after receiving the specified data packet open the back door
9, TTY hijacking.
10 virus.

Output modules plc explanation

output module plc, known as members, is a collection of individually named and independently able to complete certain functions of plc program logic controller statements (ie, aggregate program code and data structures). It has two basic characteristics: internal features and external features. Wherein the external plc digital input output module module with means to contact the external environment (i.e., program modules or other way to call the module, including input and output parameters, global variables referenced) and functional modules; internal environment is the internal characteristics of the module having the characteristics (i.e., the local module data and program codes).

plc io module is divided into several modules by function

plc io module is divided into several modules by function
plc IO module is divided into several modules according to function, such as CPU modules, input modules, output modules, power modules, and so on. The module features a communication modules plc mainframe is more some kind of modules and therefore relatively more. This can also be said to be the trend. At present, some medium-sized machine, the module features also tend to single species also increases Township. If the same OMRON Corporation intelligent plc series PLC, H machine CPU unit to contain the power, and put the power ceded Ha machine, a separate power supply module.

Input Modules plc Product Design:

input module plc has the following mechanical properties: 

Compact design: 

Rugged plastic enclosure inside include: Green plc temperature control module, status indication for signal input. Before connecting socket, through the front door to protect the label area on the front door. Easy installation: 

No slot rules; enter an address determined by the slot. 

When used in conjunction with a bus in the ET plc logic controller modules can be hot-swappable. User-friendly wiring. 

With 8,16,32 or 64-channel modules.

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.

What is the role of input and output modules are used in the fire?

Now the temperature sensitive smoke into intelligent coding and non-coding, coding can directly intelligent feedback signal to the host address (host needs to know where the fire occurred), the non-coding the feedback address signal can not be directly connected to an input module common practice module are capable of encoding such a host can receive address signals. For example now in the basement of temperature-sensitive non-coding common sense as long as the temperature of each partition to an plc input module, the host just know which partition is on the line of fire. Do not need to locate the point. The use of smoke on the ground pointing to the different needs of the specific location. Then the need for a lot of non-coding plc modules, and therefore the need for direct feedback encoder type flue gas temperature sensation address. The same is now also have coding manual alarm button code hydrant pump start button coded telephone Some devices can not be directly input and output signals such as pressure switch damper valve flow indicator signals, etc. These can only have a current output is not coded signal. Then need to use the input module, the device output power to the input module module output signal to the host. Output module is required when the host device host only direct linkage control output code modules, and then output power required to drive the linkage equipment.

Types of PLC input and output modules

Roughly divided into the digital input plc DI, digital output plc DO, analog input AI, analog output AO. Digital inputs and outputs are generally of 24V. Class 2 4 kinds of analog quantity, type 2, respectively, and the current-voltage type. There 0-10V voltage type and -10 to 10V. Current type mainly 4-20MA, 0-20MA. Then the module through A / D converter, converting the analog quantity into a + number between 32767 ~ -32768, and then exercise control

output module plc,input module plc

plc digital input output module each play any role in the PLC control system
Digital input module is an external control signal or field detection signal processing module to the PLC CPU, an external signal is generally button, proximity switches, limit switches, plc output module is based on the signal processing logic and internal logic programming input module taken into the , the results of treatment before, switch output signal is output by the high and low output module, to drive external relays, contactors, lights, solenoid valves and other components, thereby enabling the external device corresponding action

input module plc introduced in the DC chopper

DC / DC converter is a variable DC voltage into a fixed DC voltage , also known as a DC chopper . Chopper work in two ways , first pulse width modulation Ts constant change ton ( GM ), input module plc Second, frequency modulation (
(1) Buck circuit - step-down  intelligent plc chopper , the output average voltage less than the input voltage U0 Ui, of the same polarity .
(2) Boost Circuit - boost chopper , the output voltage U0 is greater than the average input voltage Ui, the same polarity .
(3) Buck-Boost circuit - a buck or boost chopper , the average output voltage is greater or less than the input voltage U0 Ui, of opposite polarity , inductive transmission. 4) Cuk circuit - a buck or boost chopper , the average output voltage is greater or less than the input  programmable logical controllers voltage U0 Ui, of opposite polarity , capacitance of the transmission . There Sepic, Zeta circuits. input module plc above non-isolated DC-DC converter circuit , isolated DC-DC converter circuit has a forward , flyback , half-bridge circuit , full bridge circuit , push-pull circuit .
Soft-switching technology makes plc intelligent controller  today's DC / DC undergone a qualitative leap , the maximum output power 300W, 600W, 800W , etc. , the corresponding power density (6.2,10,17) W/cm3, efficiency ( 80 to 90 ) % . The switching frequency (200 ~ 300) kHz, the power density has reached 27W/cm3.

Select the output module plc switch output module

The output module is required for the internal drive signal to PLC low voltage signal is converted to an external output device. The main selection should consider the type and size of the load voltage, the system latency requirements, whether state and frequent load changes.
1. Select the output mode
Digital output module has three output modes: output module plc relay output, thyristor output and transistor output. Relay outputs are cheap, both to drive an AC load, but also for the DC load, but  Programmable Output Module also for a wide range of voltage magnitude, a small voltage drop, and the ability to withstand strong transient over-voltage and over-current. But it belongs to have contact elements, its movement is slow, short life, poor reliability, and therefore, does not only apply to frequent on-off occasions. When used to drive inductive load, output module plc operating frequency does not exceed its contacts 1Hz.
For frequent load off, you should use triac output or transistor output, they are non-contact components. But only for analog output module  Triac output AC load, and transistor output can only be used for DC load.
2. Select the output wiring of different output wiring of the PLC, are generally grouped outputs and two separate outputs, outputs are grouped several output points as a group, sharing a common terminal between the groups are separated , respectively, using a different power. And each output point delimited output has a common, mutual isolation between the outputs, each output point may use a different power source. The main species Programmable Output Module  should be based on how much power the system load may be. General Integral PLC outputs both groups, there are also separate output.

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.