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.