What is the main role of PLC communication module is

communication modules plc has a wide variety of purposes, but the main effect is the IPC host or master-slave control is established between the touch screen and downstream equipment. To choose what kind of communication module to see what you control, or what is going to a conversation. But you said the monitor is not connected thereto communication, because communication module plc is taking MODBUS or DP and industrial agreements. Monitor signal only VGA signal. So the two can not be mixed together.

plc's cpu running program

Indicating step program memory address counter inside the PLC CPU, the program is running, the step of the counter is automatically incremented for each execution, the program from starting step (step number zero) sequentially perform the final step (typically END instruction), and then return to the starting step cycle operation. The time required for one cycle of operation is completed for each PLC is called a sweep. Different types of plc module, cycle scanning period between 1 microsecond to tens of microseconds. PLC Ladder programming logic in solving aspect, showing the advantages of fast, in microseconds, logic solver 1K less than 1 millisecond. It all inputs are processed as a switch, 16 (there are 32) is an analog. Large PLC using another CPU to perform analog operations. The calculated results to the PLC controller. The same plc IO module system, with PLC than with the DCS, the cost is lower (about can save about 40%).

plc pace of development in the future

With increasing degree of factory automation and china plc market expanding capacity base, the growth rate in recent years PLC in industrial countries slowed. However, growth in China and other developing very rapidly PLC. Comprehensive relevant information, in 2004 global sales of PLC is about $ 10 billion, in the field of automation occupies a very important position.module plc is a touch imitation of the original relay control principle developed, in the 1970s the PLC only switch logic controller, the first application in the automotive manufacturing industry. It is stored in the implementation of logical, sequential control, timing, counting and arithmetic instructions such operations; and through digital input and output operations to control various types of machinery or production processes.

What are the features of the PLC CPU

plc controller functions also continue to improve. With computer technology, signal processing technology, control technology continues to develop network technology and continuously improve customer demand, PLC increased the analog processing and motion control functions on the basis of the amount of processing on the switch. Today's PLC is no longer confined to logic controller, motion control, process control and other fields also play a very important role. As the product of choice of discrete control system, PLC in the 1980s and 1990s has been developing rapidly, PLC worldwide annual growth rate was maintained at 20% to 30%.

Reason thermostat module

In recent years, the rapid development of computer technology has been widely applied in all walks of life. However, with the corresponding traditional industrial module plc development cycle is long, repeated use is low, the price is high, difficult to modify and other shortcomings. As more and more automation equipment has been applied, it is for industrial control software is also rising, the traditional industrial control software has been unable to meet user requirements. How convenient use of the software to design flexible and efficient plc temperature module system has become a very important issue.

In the PLC, CPU module, I / O modules, namely what role

CPU module is the control center of the PLC. It functions in accordance with the procedures given PLC system receives and stores from the programmer type of user programs and data; check the power supply, memory, I / O and watchdog timer status, and diagnose user program syntax error. plc IO module is the interface between PLC and site control interface input channels. Therefore, the manufacturer of the PLC power supply design and manufacturing very seriously. Programming plays a role in the design and commissioning of the plc.

Advantages PLC NA series

NA Series Programmable Logic Controller (NA Series PLC) is a new generation controlling device developed with international advanced level. programmable intelligent controller adopts a series of latest achievements in the field of industrial controlling, selects a brand-new hardware and software platform, so it has fast processing capacity, strong anti-jamming performance, flexible extensible function, and plc module could cope with any complex environment and processing requirements easily and skillfully. NA Series PLC has got CE Certification and FCC Certification, various performance indexes have reached or exceeded relevant standards and are ahead of similar products.

further improve the reliability of the PLC

n order to further improve the reliability of the PLC, for large-scale PLC also uses dual-cpu module constitute a redundant system, or the use of three CPU of voting systems. Thus, even if a cpu modules plc fails, the whole system is still running.
CPU speed and memory capacity are important parameters for PLC, which determines the operating speed of the PLC, I / O number and software capacity, etc., thereby limiting the size of the control.

PlC of cpu module

plc cpu modules is the control center PLC is the core of the PLC from the nerve center of the action, each PLC has at least one CPU. It functions in accordance with the procedures given PLC system receives and stores from the programmer type of user programs and data; check the power supply, memory, I / O and watchdog timer status, and diagnose user program syntax error. When the PLC into operation, the first of its way to scan each site receiving state and data input device, and are stored in the I / O image area, then one by one to read the user program from the user program memory, after the command interpreter Press the results of the implementation of the provisions of the instruction of a logical or arithmetic fed into the I / O image area or a data register. And so after all of the user program is finished, the final transfer of data I / O image area of each output state or output register to the appropriate output device, so the cycle run until it stops running.

What is the definition of PLC, programmable logic controller

Programmable logic controller, said the English Programmable Controller, called PC. However, due to the personal computer PC is easy and (Personal Computer) confused, so people are still accustomed to using plc communication modules as an abbreviation. Electronic digital computing device operating system, it is a microprocessor core, specifically designed for applications in the industrial field, for it uses programmable memory for storage in its internal implementation of logical, sequential control, timer / counting and arithmetic operations such as operating instructions, and digital or analog input through output interface, control of all types of machinery or production processes. PLC is the product of computer technology with traditional relay contactor control technology, which overcomes the wiring relay contactor control system complex mechanical contact, low reliability, high power, versatility and flexibility shortcomings of the poor, full advantage of the microprocessor, and take care of operation and maintenance personnel to the site electrical skills and habits, especially PLC programming does not require specialized knowledge of computer programming languages, but with a set of relay ladder based simple instruction form, so that the image of the user programming, intuitive and easy to learn; debugging and troubleshooting is also very convenient. After the user to purchase the desired PLC, just follow the prompts manual, do a small amount of wiring and easy user programming work, it can flexibly and easily be applied to production practice PLC.

Programmable Logic Controller (PLC) features

Industrial control equipment reliability requirements:
① MTBF long time
② time to repair (MTTR) Short
Any failure electronic devices, usually two:
① sporadic fault. Due to the harsh external environment, such as electromagnetic interference, ultra-high temperature, ultra-low temperature, over voltage, under voltage failure caused by vibration and so on. Such failures, they do not cause damage to system components, once the environmental conditions return to normal, the system also will return to normal. But for PLC, the rear outside influence, the information stored inside may be damaged.
② permanent failure. Since the components can not be restored and the destruction caused by the fault.
If we can limit the occurrence of sporadic fault condition, the consequences will not be affected if the PLC or able to make impact in harsh environments is limited to a minimum, make programmable logic controller (plc) suppliers automatically disappear after the harsh conditions return to normal, so that we can improve MTBF time; if we can increase the number of diagnostic measures and appropriate means of protection in the PLC, when a permanent failure, can quickly find the point of failure and faults locally, can reduce mean time to repair the PLC. To this end, each PLC manufacturer has taken various measures in terms of hardware and software, so that PLC in addition to their strong self-diagnostic capabilities, in time with an error message, stop waiting for repair, but also make the PLC has a very strong anti-jamming capability.

Micro & Nano programmable control system

Our micro and nano-PLC can provide an economical solution to meet the basic needs of a simple mechanical control, including relay replacement, and simple control timing and logic. The controller uses a compact package, integrated plc IO module and communication, and easy to use, ideal for conveyor automation, security systems and building and parking lot lighting applications projects.

PLC basic instruction Overview

FX series Plc logic controllers basic logic instructions 20 or 27, stepping instruction 2, features more than 100 instructions (different series vary).
FX2N plc temperature control module  a total of 27 basic logic instructions, which contains 20 basic logic instructions some sub-series plc input output modules.
Instruction fetch and output instruction (LD / LDI / LDP / LDF / OUT)
(1) LD (instruction fetch) a normally open contact and left instruction bus connection, a normally open contact each logical row starting with this directive.
(2) LDI (negated instruction) a normally closed contact and left the bus connection instruction, a normally closed contact each logical row starting with this directive.
(3) LDP (transition instruction fetch) normally open contact with the left leading edge detection instruction bus connected only at the rising edge of the specified bit device is turned on when a scan cycle (from the OFF → ON).
(4) LDF (falling instruction fetch) normally closed contacts of falling edge detection instruction and left the bus connection.
(5) OUT (output command) coil for driving instruction, also known as output instruction.

Programmable Logic Controller (PLC) of the workload of the design and

construction of the control system
Since the digital output plc using a relay control system software to replace a large number of intermediate relay, time relays, counters and other devices, the control cabinet design and installation of wiring workload greatly reduced. Meanwhile, plc controller manufacturer user program can simulate debugging in laboratory, but also reduce the workload of site commissioning. Also, due to the low failure rate micro smart plc and strong monitoring, modular, etc., so maintenance is also very convenient.

Programmable Logic Controller (PLC) software measures:

We have a strong self-test and protection.
① fault detection - software periodically to detect the external environment, such as a power failure, under voltage, battery voltage is too low and strong interference signals. So that timely treatment.
② Information Protection and Recovery - When sporadic fault condition occurs, does not destroy the plc cpu modules's internal information. Once the fault condition is removed, you can return to normal, continue the original program of work. Therefore, intelligent plc when the fault condition is detected, immediately put the current state stored in the memory, software with the memory is closed to the memory of any action to prevent the storage of information is obliterated.
③ Set the Watchdog WDT (Watchdog) - If the program execution time per cycle than the WDT specified time, indicating the program into an infinite loop, call the police.
④ strengthen inspection and verification procedures - once the program is wrong, call the police, and stops executing.
⑤ the program and dynamic data backup battery - after a power outage, use battery-powered back-up, and information about the status will not be lost.
Plc modules factory pilot project, there is an immunity test. It is required to withstand the amplitude of 1000V, the rise time 1nS, a pulse width of the pulse 1μS of interference. In general, the average time between failures of up to hundreds of thousands - tens of millions of hours; the system can be made up to 4 to 50,000 hours or longer.

Programmable Logic Controller (PLC) hardware measures:

The main modules are used large-scale or large scale integrated circuits, a large number of switching operations performed by non-contact electronic memory, I / O system design have improved the channel protection and signal conditioning circuit.
① shield - to power transformers, CPU, programmers and other major components, the use of electrical conductivity, magnetic shielding material good, to prevent outside interference.
② filter - the power supply system and an input line filter in various forms, such as LC or π-type filter network to eliminate or suppress high frequency interference, but also weakened the interaction between the various modules.
③ power adjustment and protection - the core components of the microprocessor needed a + 5V supply, the use of multi-stage filter and make adjustments with the integrated voltage regulator to adapt to fluctuations in the exchange and over-grid voltage, under influence of voltage.
④ isolation - between the microprocessor and plc IO module circuits, opto-isolated, effectively isolate the electrical connection between the I / O interface with the CPU contact, reducing failures and malfunctions; between the I / O port also isolated from each other.
⑤ with modular structure - This structure helps in case of failure to repair short. Once identified a faulty module can easily be replaced quickly, allowing the system to resume normal work; also helps to accelerate find the cause of the fault.

Programmable Logic Controller (PLC) features

Industrial control equipment reliability requirements:
① MTBF long time
② time to repair (MTTR) Short
Any failure electronic devices, usually two:
① sporadic fault. Due to the harsh external environment, such as electromagnetic interference, ultra-high temperature, ultra-low temperature, over voltage, under voltage failure caused by vibration and so on. Such failures, they do not cause damage to system components, once the environmental conditions return to normal, the system also will return to normal. But for plc analog input output module, the rear outside influence, the information stored inside may be damaged.
② permanent failure. Since the components can not be restored and the destruction caused by the fault.
If we can limit the occurrence of sporadic fault condition, the consequences will not be affected if the plc IO module or able to make impact in harsh environments is limited to a minimum, make PLC automatically disappear after the harsh conditions return to normal, so that we can improve MTBF time; if we can increase the number of diagnostic measures and appropriate means of protection in the PLC, when a permanent failure, can quickly find the point of failure and faults locally, can reduce mean time to repair the plc communication modules. To this end, each PLC manufacturer has taken various measures in terms of hardware and software, so that PLC in addition to their strong self-diagnostic capabilities, in time with an error message, stop waiting for repair, but also make the PLC has a very strong anti-jamming capability.

CPU module key switch description

CPU module key switch description

RUN running mode and REM remote mode

Run the CPU, the user cannot be stopped by software; cannot modify the program, including a full download and online download, not mandatory, cpu modules plc programming software can not write variables (HMI can write variables); can not be reset, cold reduction and empty application.

From the "run" or "PRG mode dial to" REM "mode, CPU working mode to maintain the state, users can through software running or stopping CPU;  digital output plc can modify the program online, can force, you can also write variables can be reset, cold reduction and empty applications.

Sinoplc CPU module structure

Sinoplc large PLC with advanced computer technology, control technology, communication technology and signal processing technology, can provide personalized solutions for users of different industrial sectors for logic
control, sequential control, micro smart plc process control, drive control and motion control and other fields.

Applications include electric power, petrochemical, chemical, metallurgy, energy, transportation, municipal, textile, food, paper, printing, pharmaceutical, mining, intelligent buildings, cpu modules plc air conditioning and refrigeration.


Provide LED lights, key switch, RS232 interfaces, digital output plc  RS485 interfaces, PROFIBUS-DP bus interface, Ethernet interface, SD memory card slot and a spare battery slot on the CPU module panel.

Compared with traditonal PLC,sinoplc large PLC

Sinoplc large-scale programmable controller (PLC, cpu modules plc ) Hollysys in summing up the control system design of fifteen years and thousands of sets of project implementation experience based on the launch of application in the field of medium and high performance control products.

Compared with the traditional PLC, LK can be programmable controller with full integration of the advantages of DCS and PLC, the high performance analog processing technology, miniaturization structure design, open, industry standard, universal system platform, small plc make the product not only has the powerful function and excellent performance, but also has higher reliability, better openness and ease of use.