DCS selection: Yokogawa CS3000 or Zhejiang University SUPCON?

The leader’s words tell you to choose Zhejiang University Central Control. To be honest, it is easy to reach the international advanced level in terms of software, but concepts and hardware do not happen overnight. 500 points, it’s just a small device, so it’s better to choose domestic ones. After so many years of development, Zhejiang University SUPCON has almost the same price. Although I have never used their products, I have only dealt with them.

500 points is a very small device. If you don’t have too high requirements for self-protection, just choose Zhejiang University Central Control DCS. We have Zhejiang University Central Control DCS here. The configuration interface and operation interface are very smooth and convenient to use. After all, it is an independent company in China and takes care of many Chinese people.* used

Choosing the one with the best price/performance ratio means that you can choose the cheapest one, and you have no special requirements. As long as it's technically satisfactory.

Sometimes domestic products are still very useful.

As long as it can meet the functional requirements, you don't have to choose foreign ones.

Our company uses both Yokogawa CS3000 and Zhejiang University Zhongkong JX-300. Let me briefly introduce the situation for reference. For general control, the DCS of both companies can definitely meet the needs. hardware: Yokogawa has many faults and I/O cards with many bad pixels. Zhejiang University's central control has fewer faults, but the I/O card does not have point isolation. If there is a problem with one point, it will affect the adjacent points. software: Yokogawa's features are many and complex. Zhejiang University Central Control is simple and has a full Chinese interface. price: If there is a bidding process, Zhejiang University Central Control's will not necessarily be cheap. maintain: Zhejiang University Central Control is convenient. Spare parts: Yokogawa's prices are high. Serve: All good.

MLZJ’s speech: Our company uses both Yokogawa CS3000 and Zhejiang University Zhongkong JX-300. Let me briefly introduce the situation for reference. For general control, the DCS of both companies can definitely meet the needs. hardware: Yokogawa has many faults and I/O cards with many bad pixels. Zhejiang University's central control has fewer faults, but the I/O card does not have point isolation. If there is a problem with one point, it will affect the adjacent points. software: Yokogawa's features are many and complex. Zhejiang University Central Control is simple and has a full Chinese interface. price: If there is a bidding process, Zhejiang University Central Control's will not necessarily be cheap. maintain: Zhejiang University Central Control is convenient. Spare parts: Yokogawa's prices are high. Serve: All good. I think something needs to be explained: Yokogawa's card components have very low faults, which have been verified on site. On the contrary, Zhejiang University's card components have a correspondingly higher number of faults. Domestic card components have some problems in the aging test. In terms of software, many functions are not complicated, such as control modules. Without rich modules, configuration will be very troublesome. The domestic DCS uses a Chinese interface, which is very convenient. Price, the price of domestic DCS is about 30% of that in China. The same goes for spare parts.

There seems to be no comparison between the two. Generally speaking, there is only a comparison between domestic products and domestic products, and a comparison between foreign products and foreign products.； For now, the price gap between domestic and imported products is still relatively large. ； There is no big problem in terms of use, as long as * Just get used to it.

I don’t completely agree. The starting points for foreign DCS and domestic DCS are different, but the competitive environment they face in the Chinese market is the same, and both should learn from each other’s strengths. The difficulties faced at home are greater. Technology is the foundation of development. If technology cannot improve, everything will be useless. Foreign countries do not have advantages in everything, such as flexibility, price, etc. They are all competitors and can be compared.

Personally, I feel that a 500-point system can be fully qualified with a domestic system. There is no need to use a foreign system, and the domestic system is also more cost-effective.

My company uses Beijing Hollysys products, and overall they are OK.

My company uses Zhejiang University Zhongkong, which is okay. But it cannot be downloaded online, and the performance of the hardware module is okay.

Use Zhejiang University Zhongkong, Mr. Chu’s. :lol

You should evaluate the hazards of the process before deciding which system to use. Yokogawa's system has a very low failure rate, but the system has low flexibility and is very rigid in planning.

I said that the choice of DCS is becoming more and more popular nowadays. The reason is that there are many types and quantities of DCS products to choose from. Especially for domestic products, their functions are becoming more and more perfect, and their reliability is gradually approaching that of imported products. Choosing to use DCS can improve the corporate image and is much more elegant than panel-mounted unit instruments. And after the I/O points increase to a certain amount, the total investment and total operating expenses will not increase much compared to conventional unit instruments. There are many varieties of DCS (PLC), with different structural types, performance, capacity, command systems, programming methods, prices, etc., and their applicable occasions are only slightly different. Generally speaking, DCS products occupying a certain market can meet the needs of general process production. So, how to make a reasonable choice for this type of product? Some people say that DCS model selection is to select the most reliable, most convenient maintenance and use, and optimized model with cost-effectiveness on the premise that the functions meet the requirements. As everyone knows, how many models currently have functions that cannot meet demand? “The most reliable, most convenient to maintain and use" cannot be the best performance-price ratio. If so, please believe that it is just a noisy one. For more companies, the model they ultimately choose depends on the user's preference for the manufacturer's market operations. 1. Macroscopic selection 1. 1 Today's DCS products, whether domestic or imported, are now relatively reliable and can meet the needs of general process production. Please don’t believe anyone who claims that the product is fault-free. There is no product in the world that is fault-free. A DCS failure will generally not disrupt the continuous production of the device. ； If continuity is damaged, it may not be a problem with the system itself. It is often caused by improper construction, use and maintenance, or lack of spare parts. 1. 2 When choosing which model to choose, you must carefully analyze the special DCS requirements of the process.: For example, some require fast interlocking, some processes have high continuity, some processes require high reliability, etc. The above requirements cannot be made too qualitative to be implemented, so that the final result is: Regardless of the process, the requirements are the same. Therefore, people who engage in self-control had better know a little bit about craftsmanship, otherwise they will not be able to truly understand the true meaning. During the specific analysis, you can make a preliminary inventory of what models are used in this process at home and abroad (imported famous brands or domestic famous brands), how much it costs to start and stop the process, and the assessment of safety threats caused by sudden failure and shutdown, etc., so as to compare with the increased investment in DCS. The failure of the DCS system itself is a very low-probability event. Don't worry too much about limited funds in these aspects. My suggestion is: High value-added products, high-risk processes, such as expensive products (such as some organic chemical products), those that are flammable, explosive, toxic and without conventional treatment measures, those that are difficult to clear due to sudden stops or the dredging losses are great, those that cause great losses after breaking continuity, complex control strategies that can produce huge benefits, etc., use imported products. The reason is: 1. Comparing what I felt when I worked in a Japanese electronics factory for half a year in 1993 with the production process of domestic famous brand DCS factories that I visited from 1998 to 2002, the Japanese factories’ quality control in all aspects is incomparable to domestic factories at least in recent times. 2. Foreign famous brand manufacturers still enjoy monopoly patents on certain complex control strategy software. For example, the control software for a certain organic process indicator can be sold for several million US dollars per set. Some people buy it because it can produce greater benefits. 1. 3 For a large enterprise system, the model should be unified as much as possible. In this way, DCS modules of the same model can be used as backup for each other, which facilitates the procurement and management of spare parts. ； At the same time, its unified functions and programming methods are also conducive to the training of technical forces, the improvement of technical levels and the development of functions. ； In addition, because its external devices are common and resources can be shared, when equipped with a host computer, multiple units that control independent systems can be connected into a multi-level distributed control system, which facilitates mutual communication and centralized management. 1. 4 The company gives priority to the selection of products from current and future stakeholders from a strategic perspective. 2. Micro-selection 2.1 Number of operation station configurations. Generally speaking, process operations performed on DCS are infrequent. The "insufficiency" in the number of operating stations is mainly reflected in the period when the new device has just been started. The number of key operators minus one may be considered as a principle. Besides, you can add more at any time if it is insufficient in the future, or use a temporary general-purpose PC for temporary use. A domestic operating station costs RMB 30,000 to RMB 40,000. 2. 2. Determine the number of I/O points. When determining the required number of I/O points according to the requirements of the control system, add an additional 10% to 20% reserve to allow for additional control functions at any time. Too much is also a waste of resources. However, it must be clarified with the supplier that system expansion should be simple and convenient, otherwise the cost may be high. For a control object, the number of I/O points should also be different due to different control methods or different programming levels. 2. 3 Card selection Generally speaking, DCS system analog input signal (high level) 0.1%, analog input signal (low level) 0.2%, analog output signal 0.2%, and pulse input card 0.2%FS are sufficient to meet usage needs. However, it should be noted that the analog input terminal or standard signal input card responds to some fast signals. Give an example to illustrate this problem: When a high-precision imported meter with a cumulative function uses a 4-20mA signal, the cumulative value of the field meter differs from the DCS cumulative value by about 1.2%. After using the pulse input channel, the deviation is reduced to about 0.09%. Another domestic calculator with an accuracy of 0.3% is about 0.1% different from the DCS. This illustrates two problems. First: The response characteristics of the totalizer's own measurement affect its own measurement accuracy. ； The authenticity of the cumulative meter output results is seriously affected by the response of the DCS to the measurement input. The analog card accuracy indicator corresponds to a signal that does not change much. Therefore, in practical applications, for measurement of important trade materials with poor compliance, DCS is best to use pulse channels. And after a long period of comparison, this method is very consistent. Don't mechanically think that the pulse input card's 0.2% FS accuracy is lower than the analog input signal (high level) 0.1% accuracy. 2. 4 Terminal board selection 2, 4, 1 In the application of DCS mentioned in the above article in important occasions, it is best to choose redundant or online replacement terminal board. The second thing is to note that the terminal board terminals should be "strong". In order to ensure mechanical strength and reliable contact during actual construction, the torque on the terminals is often very large. Some foreign technicians use even greater force, which is prone to terminal slippage. It is best to change the settings of jumpers 2, 4, and 2 online. 2, 4, 3 Pay attention to the lightning protection design of the product. To evaluate this aspect, it is necessary for the manufacturer to cooperate in providing circuit diagrams and for the user to have a good understanding of lightning protection design. Generally speaking, any industrial instrument, control system, etc. has certain lightning protection capabilities, otherwise it will not be able to gain a foothold in the market. If by chance the equipment encounters a strong direct lightning strike, no professional lightning protection product may be able to withstand it! The performance and price of lightning protection products at home and abroad vary greatly. There have been examples of lightning protection devices with a million yuan investment in supporting DCS. It is also difficult to analyze the effect. There are many accidental factors and many reasons for whether the equipment is attacked by lightning. Generally, the probability is very low. As long as there is no problem with the conventional lightning protection construction, there is no need to conduct too much analysis, and there is no need to spend huge sums of money to consider this aspect. Exceptions are made for places with high lightning strikes and places with special needs. If too much attention is paid to lightning protection issues, manufacturers will often propose many "harsh" construction measures, which will increase many other costs. Our company's DCS was put into use in June 2003. On July 22, a lightning strike caused two pieces of FW372 and FW352TC to be damaged. At the same time, four isolators and an SO2 analyzer (ABB) were also damaged. On April 9, 2006, a lightning strike damaged four thermocouple channels and the SO2 analyzer (ABB). Judging from the scope of the accident, it was concentrated at the converter equipment. After this accident, in order to improve the lightning protection characteristics of the DCS card, varistors and ceramic gas discharge tubes were installed on the input and output of the UPS, and transient suppression diodes were connected to all analog terminal circuits of the DCS. Since then, although there have been many thunderstorms, there has been no accident of card damage. However, this does not mean that everything is fine. At least, no lightning protection components have been added between the circuit and the ground. Because adding is troublesome and the performance cannot be evaluated, and only using a complete set of spare parts is the most reliable measure to prevent various situations. At the same time, requirements for necessary spare parts should be put forward when bidding. 2.5 Software Selection During the system selection process, users should have an understanding of the software functions of the selected DCS product. Typically, a system's software is used to handle the control hardware that a controller has. In actual applications, there may not necessarily be many requirements for functions, but more attention is often paid to the stability and reliability of its general applications. Pay more attention to the common control function modules that are fully configured and should be easy to use. However, some application systems also need to control software functions other than hardware components. For example, an application may include special control or data acquisition functionality that requires complex mathematical calculations and data processing operations. The choice of instruction set will determine how easy it is to implement the software task. The available instruction set will directly affect the time required to implement the control program and the time it takes to execute the program. 2. 6 Others 2. 6. 1 Pay attention to verify the stability of the channel, including redundant switching. The accuracy should preferably be within a reasonable range. 2, 6, 2 Uninterruptible power supply should be included in the overall reliability consideration of DCS. In actual operation, the main unit has been damaged or the battery has failed in all the large and medium-sized imported UPSs (above 15KVA, ABB and Jinda products) and domestic or imported small UPSs (below 5KVA) that I have come into contact with. Therefore, if a power outage has a great impact on the emergency response of the production process, it is strongly recommended that the UPS be configured in redundancy. For example, 6KVA-UPS and solar battery redundant configuration, the total price does not exceed 40,000, which should be acceptable. If you do not configure redundancy in the initial stage, it is strongly recommended that the host must have redundancy function and the battery should be imported from Sunshine (battery is twice as expensive, but absolutely worth it! ) 2.6.3 Collect and set the initial PID parameters of the system as much as possible, which reduces a lot of risks when the new device is put into automatic operation. Conclusion: Our company uses the Zhejiang University Zhongkong WebField ECS-100 decentralized control system. Since the system was put into operation in June 2003, the FW351 card has crashed, but there has been no incident of device shutdown or production shutdown due to the system itself. The overall system operation is safe. It can be said that it is a blessing for a system to be able to do this. I have also used ABB and Siemens systems. That was in the 1990s, and the cards, keyboards, hard drives, and ball markers all failed. However, the prices at that time were unimaginably high, and 10 times was not an exaggeration. I hope everyone will use more domestic brands and support China. China’s progress and development require the support of the whole society! !

The so-called fault level has a lot to do with the level of users and maintenance level. Our Zhejiang University central control system has never had any card or point breakage in the past few years. I think the central control is enough for you. Of course, CS has many more functions and the price is higher.

A good system must be equipped with good online instruments to truly demonstrate its advantages. I think the system of Zhejiang University is still good. ECS-100 achieves channel-to-channel isolation, which is very stable and cost-effective.

Technically, what process depends on it? Zhongkong: Conventional chemicals and Lishi: Boiler Shanghai Xinhua: Power generation Yokogawa: I’m not very familiar with the key to business public relations. It depends on the leader haha