Questions about DCS smart cards, channel isolation, and bottom plate isolation barriers

Haha, let’s talk about the first one. I personally feel it is not practical. Although the system has this function, we still* Use a handheld communicator to make parameter changes on site

1. Please tell me if the imported DCS is equipped with AMS software, smart cards, and smart isolation barriers, and the field table data can be read on the operating station. How necessary is this? Is this used a lot now? I heard it's very slow. answer: First of all, AMS software is Emerson's concept, and other manufacturers do not call it this name. Generally translated as asset management system, intelligent field equipment management system. The Ganges River seems to be called RPM. Smart card? Smart isolation barrier? Let’s give an example. In Emerson DeltaV system, chemical environment. The field is an intrinsically safe instrument that supports hart, and the AI ​​line advanced isolation barrier cabinet passes through the isolation barrier (the isolation barrier must be an intelligent type that supports hart), and then goes to the AI ​​card from the isolation barrier, and the AI ​​card must also support hart. Then the field instrument can be diagnosed and repaired through the AMS software on the "Engineer Station". The operator station only monitors the process value of this instrument - PV. The engineering station can calibrate and adjust the zero point drift. Change the range. Even check the serial number, view maintenance records, etc. In addition, let's say this is the pressure change of 3051S, but it is a high temperature type. We mainly look at the pressure value, but we may occasionally care about the temperature of the pressure change. . . It is a high-temperature type, but if the furnace temperature is too high, it will cause the temperature of the pressure-deforming diaphragm to be too high, and it will still be damaged. At this time, the parameter "diaphragm temperature" of the pressure change can also be viewed and monitored. There are a lot of people doing this, and it’s not too slow. Hart The old version only has a speed of 1200. The new version has a speed of 9600. Not bad. It’s not like we were counting on this for surveillance. What really needs to be monitored at all times is the process value coming from 4-20mA. What diagnostic information is included in the Hart protocol, you may want to look at it when needed. At the same time, I rarely go to OS sites, usually ES sites. ----I don't know if what I said is what you meant. 2. DCS analog cards have three levels: group isolation, channel isolation, and individual converters for each channel. In the case of using an isolation safety barrier for DCS, how necessary is it to control a separate AD or DA converter for each channel of the card? I think it's just that the conversion is faster, and a little isolation is enough. The key is which card company can do this? Foxbro's 8-point cards seem to work, but can Honey and Yokogawa's 16-point cards work? It feels like the more points you have, the less you can do. This is an old topic. In fact, I don't understand the so-called separate converter for each channel. Is it an A/D or D/A converter? At present, DCS's AI and AO cards are generally channel grouped and isolated. For example, ABB S800-AI810 is a set of 8. Siemens SM331-7KF02 comes in sets of 2, totaling 4 sets. There are 8 groups of Ganges, 2 groups in total, and there are also 8 AI points, isolated point by point. Point-to-point isolation, also called single-channel isolation, is also done by many manufacturers. In theory, such a card can penetrate any channel without affecting other channels as long as the card is not damaged as a whole or the power supply is not damaged. Therefore, each point is independent. If you add an external signal isolation period to achieve point isolation, then there is no need to add a signal isolator. For group-isolated AI and Ao cards, it is necessary to prevent single-click penetration or short circuit from affecting other points. It is generally recommended to add a signal isolator. As for single-channel converters, almost all current analog cards have independent internal A/D conversion chips. This is worthless. So I don't understand what you mean by single channel A/D conversion. Generally speaking, Yokogawa has single-point isolation cards and group isolation cards. Foxboro's 8AI is a single point isolation card. Honeywell's PM series 16AI is a group isolation card, but adding FTA can also achieve the effect of single point isolation. ABB S800 is also a group isolation card. Siemens' ET200m has a wide range of types, including single-point isolation and group isolation. Cards with single-point isolation are much more expensive than cards with group isolation. 3. Nowadays, the isolation barrier is designed to use a base plate type, which is more convenient for wiring. However, I heard that once the base plate is damaged, the isolation barrier of the entire board may not be able to be used normally. Do you use the base plate type or the guide rail type these days? Talk about the application of bottom plate isolation barrier? The bottom plate of the safety barrier can be integrated or single, both are useful. In the base plate integration, every 8 or 16 isolators are plugged into a board, just like the relay boards often sold outside. The isolation barrier is plug-in type, and then the base plate provides unified power supply, usually 2 channels of DC24V. Then there are dedicated connection cables from the baseboard to the AI ​​and AO cards, just plug them in and it's OK. This looks neat and easy to replace a single isolation grid. For a single unit, each isolation barrier must be powered separately and wired separately to each IO point. Theoretically. The risk of a single unit is small, and there is no base plate broken, which completely eliminates this worry. But in reality, the difference is not as big as we think. It turns out that the bottom plate type is also very stable. Just don't have too many safety barriers on each base plate. The single-piece safety mountain can currently be installed on a power supply rail. In this way, two power supply modules are equipped to supply power to the entire guide rail, and then all safety barriers inserted on the guide rail are powered. But the wiring to the Io point still needs to be connected separately. For the same reason, don't insert too many safety barriers on each guide rail. Otherwise, if there is a problem with the guide rail, the impact will be too great. There must be 2 power supply modules, or more than 2, never just one, haha.

Thank you so much! It seems that some expressions are not professional and rigorous enough. Please explain.: Smart cards refer to IO cards that support Hart. Smart isolation barrier refers to an isolation safety barrier that supports HART transmission. I have seen some circuit diagrams and my understanding is that: Group isolation is a group of IO points sharing the DC power supply and AD or DA converter in the IO card. Point-to-point isolation is a separate DC power supply for each channel in the card, while the AD or DA converter is shared within the card and works in a switching manner between channels. This kind of isolation is also relative. Generally, the burnout of the channel will not affect the converter. If it does, the entire card will be scrapped. Individual converters for each channel refer to IO cards that independently set up the DC power supply and AD or DA converter in the card for each channel. In this way, the card conversion speed of each channel's exclusive converter will definitely be faster and more reliable. Point-to-point isolation is more expensive than group isolation. Cards with exclusive AD or DA converters for each channel are even more expensive, and each card does not have many points. Someone told me that it is possible to have an exclusive converter for each point of the 8-point card, but it is mysterious for the 16-point card. Some manufacturers' manuals clearly state that more manufacturers intentionally avoid this matter, so they want to find out what kind of card they have. For example, Central Control clearly stated that: The JX-300 AI card model without I is group isolation, and the model with I is point isolation; all analog cards of ECS-100 are point isolation.

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