CP60-CPU CP60 CP40B-CPU CP40B   工控產(chǎn)品  自動化設(shè)備

CP60-CPU CP60 CP40B-CPU CP40B   工控產(chǎn)品  自動化設(shè)備

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【主營產(chǎn)品】

貝利Bailey。Allen-Bradley。?？怂共_Foxboro。

DCS  PLC  伺服系統(tǒng) 機器人系統(tǒng) 配件。Schneider施耐德。艾默生EMERSON。XYCOM。Woodward伍德沃德。西屋Westinghouse。Honeywell霍尼韋爾。WEStation系統(tǒng)備件。

英維思Triconex。Motorola摩托羅拉。羅克韋爾Rockwell。ABB。XYCOM。本特利Bently。GE通用電氣。Yaskawa安川。。Bosch Rexroth博世力士樂。Yokogawa橫河。Siemens(西門子)。Reliance。Modicon莫迪康

The reliability of products is originally reflected in the failure rate. The lower the failure rate is, the higher the reliability is. In order to reduce the failure rate, PLC manufacturers should first find the failure factors, which should be analyzed from the internal structure and external environment of PLC.

From the internal structure of PLC, it can be divided into software and hardware, and the software can be divided into bottom software, using software and programming software; Hardware is divided into CPU, power supply, I / O, communication, connector and mechanical structure.

Firstly, the failure rate of PLC hardware is analyzed. Because of the special program structure of PLC, in terms of CPU and I / O circuit, the failure rate is mainly related to the hardware structure planning, the selection of components, and the production process. The selection of hardware planning and meta equipment mainly depends on the level and experience of R & D. moreover, after the use of several generations of products, we can find the existing problems. For manufacturers with a certain history and scale of use, they can control this aspect better. In terms of production technology, manufacturers with their own production lines can analyze the characteristics of their own production lines through repeated production, especially the shortcomings of the production process. Therefore, generally, even if the first two batches of each product have problems, they can improve and improve the production line through fault diagnosis. Therefore, there will not be too many problems in this aspect.

As for the power supply, the power supply of PLC not only supplies power to PLC itself, but also supplies power to external instruments. In addition, the number of I / O modules (or expanded I / O modules) of PLC itself changes, so the change of load is relatively large. In terms of planning, we can only think according to the biggest consideration. However, because the power supply is a power equipment, it is easy to heat up. The temperature rise of the power equipment will further affect the functions of other surrounding equipment, especially when the over-current or over-voltage condition exists, it will burn out the components. However, if the margin is too large, the cost will be added a lot, Power supply module is a relatively easy to show some of the fault. In general, the problem to be solved is not only to select high-quality equipment, but also to consider a large enough margin in terms of planning at the expense of some costs.

Some of the communication, PLC in the use of some of the most customer complaints, PLC communication generally has a serial port (RS232, RS485), Ethernet, and industrial field bus network port. Because most of these communication methods come from personal computers, many standard communication interface standards are not very suitable for industrial field, such as voltage level, fault tolerance rate and so on. Therefore, the communication port presents the probability comparison of the problem. From the perspective of product planning, it is a very challenging task that how to enhance the adaptability of communication port to the outside world through the planning of software and hardware, and how to reduce the external interference to PLC internal communication through adopting various anti-interference methods. What's more, since it's communication, it must involve protocol issues, and it will also involve the other party of communication, such as computer, human-machine interface, other PLC, frequency converter, field intelligent instrument or intelligent equipment, etc. many communication failures are caused by the problem of communication object or communication parameter setting, rather than the real failure of PLC, This is to test the level and experience of the technicians who are responsible for debugging in the device and use of PLC.

Although the proportion of connector in the cost of PLC is not very large, it is the component that often presents fault in the process of using PLC. Poor touch is the most common phenomenon. Even if the terminal of PLC is well planned, if the user is not very careful in wiring, it will also present the problem of poor touch. If the identification of the terminal is not very clear and eye-catching, maybe the wiring personnel will be distracted, and the wrong line will be connected. If the strong current is connected to the signal terminal, the damage of PLC will be formed immediately.

From the aspect of planning, the planning of PLC terminals is also very careful. Not only the terminals with outstanding touch function should be selected, but also the use status of industrial site, the durability of terminals, and the convenience of connecting terminals in installation, debugging and repair should be considered. In addition, the identification of terminals is often ignored by many PLC manufacturers. How to think about the identification of terminals humanely is to test the psychological common sense level of PLC planners.

The mechanical structure of PLC is mainly shell and bottom plate. Not only the connection and fixation of internal circuit board, communication interface and terminal, but also the heat dissipation of PLC, the prevention of external dust, water vapor and impact, and the shielding of oscillation and even electromagnetic interference should be considered. In addition, structure planning is the primary manifestation of product appearance. Therefore, product structure planning not only needs to understand all kinds of electrical and mechanical knowledge, but also needs to consider the usage habits of on-site users, and also needs to have enough artistic accomplishment.

Software, from the perspective of development, to complete all the functions of PLC has been a very huge system engineering, and some of these jobs in the entire PLC system software planning and programming, originally only a small part of all the workload. Others, mostly around the reliability aspect, software planning and programming. Software reliability planning, first of all to think about PLC in normal operation of various possible emergencies, to carry out fault-tolerant planning. Because PLC directly deals with all kinds of hardware, including CPU address, data, register, cache, and external input and output control, and many hardware will have different changes due to various influences. Therefore, the internal fault-tolerant processing is already a large workload, and there are no certain rules and precedents to follow in these aspects of programming, It all depends on experience. In addition, there are some external environmental impacts, such as electromagnetic interference, temperature change, signal fault, communication fault, overrun change of all kinds of signals, and human operation faults, such as programming fault, wiring fault and operation fault; We must carry out the necessary fault-tolerant planning, which depends on the accumulation of experience.