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.

The development of sinoplc large cpu modules plc

In the development process of sinoplc large PLC, Hollysys fully consider the users of the system security, performance, structure, applicability, and interface of the demand expansion, cpu modules plc efforts to build the system has the characteristics of high performance, high reliability, novel design, easy to use, open and flexible, can bring many benefits to the user.

Use sinoplc large PLC, you can not only solutions based on the flexibility to customize the site actual demand, perfect to realize the control target, to reduce operating costs, input module plc improve work efficiency and system redundancy schemes, compact structure, humanized design can to you thought, do you seek, make you relaxed freely, anytime, anywhere enjoying the joy of working!

The system control center, PLC CPU module

The CPU module is the control center of the system, the user will be prepared to complete the program is downloaded to the CPU module, the CPU module after the start of a cycle of user program execution, each cycle should be read into the process information, cpu modules plc  logic calculation, output calculation results, but also the timing or by user set time, high-speed counting, event processing and communication interrupt process.

The powerful LK PLC, is the first large-scale programmable controller, system
implementation experience based on Hollysys company has accumulated fifteen years of research, high-speed counter modules development and engineering control system, in-depth study and absorb the essence of the international similar products, PLC years of intensive and meticulous farming.