How to design the control method/control system
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I currently work as a instrumentation technician in a private company that produces ion-exchange membrane caustic soda, and the company plans to launch a PVC production project. The ion-exchange membrane caustic soda plant has been installed, but procedures are still being completed due to incomplete documentation. One of these items requires me to prepare design-related materials: the main control methods used in the factory, and a description of the control system design (the design institute will not handle this). I was unable to find any specific information using Baidu or Google either. I’m not sure if any kind-hearted person out there has similar materials (a link would also work), and I hope they can share them with me. It would be great if there were information on both ion-exchange membrane caustic soda and PVC (produced by the acetylene method). I am extremely grateful. My QQ email address: 77283495@qq.com
If the design institute refuses to carry out the work, it must be because the payment has not been made. Under the current circumstances, the client can definitely take advantage of the design institute – if they refuse to help, do they still expect to receive their payment? Well, back to the topic. When preparing a description for control system design, it’s important to clarify what process needs to be controlled, what IO points are available (list them out: address, name, signal type, source, destination), whether redundancy is required, whether hot-swapping support is needed, what requirements exist regarding IO capacity (it’s recommended to have a margin of 20% or more), what preferences you have regarding the brand of the control system, what requirements there are for the overall system topology, what requirements your host computer has, whether the computer and related equipment will be supplied as one unit, whether a UPS is needed, whether you want the supplier to also develop the control programs, and what requirements there are for the auxiliary components in the control cabinet (terminal blocks, power supplies, relays, etc.) – although these components are small, poor quality ones can cause problems later on. If the IO cabinets are located in different rooms, remote IO access is required; if the IO devices need to pass through safety barriers, then whether those barriers will be supplied along with the rest of the system, what the delivery timeline is, and whether any training for staff is required. I suggest that you clearly outline all the technical requirements to avoid any misunderstandings. Leave the design of the cabinets, wiring diagrams, and programming/debugging tasks to the supplier; just have them review the drawings in advance. If you’re the client and handle all the design work yourself, how can you possibly act like a boss?
The design institute refuses to carry out the work; even if we provide the necessary information, it is only for reference purposes. For the same project, different companies may use different approaches. So what you need to do now is explain this matter to your supervisor as soon as possible, so that by the time it’s time, the responsibility won’t fall on you alone
Another option is to engage a DCS manufacturer to carry out the integration; nowadays, larger DCS manufacturers can all provide engineering services
A design description, as the name implies, is an explanation provided by the designer; it must certainly come from the designer themselves – anyone else who prepares such a description is merely guessing!
I’m very grateful for Haiyou’s generous help, but it seems like no experts have shown up. I’ve completed the control technology required by my supervisor, though it was done rather reluctantly. Let’s leave it at that for this question. In simple terms, it is a general overview of control systems, including DCS, PLC, ESD, etc. DCS is the main aspect; it includes single-loop control, complex control loops (which require considerable effort – not only are there specifications for the control loops, but also corresponding process principles, control calculations, and some programming is needed), as well as safety interlock control (this part requires thoroughness and detail – the interlock logic diagrams can be annotated and then copied and pasted). Add some introductions and conclusions and that’s pretty much it. Due to differences in manufacturing processes and design institutes, the design solutions will certainly vary, but these elements can all be used as references. Since it’s not yet clear whether the review will be approved, I won’t upload mine for now. If any of you need it, feel free to leave a message and I’ll send it to you directly.
It’s a serious matter; even experts might not do such things for complete strangers, as this requires years of experience. Taking on this task is also a form of training, and it allows one to add a valuable item to their resume
I was involved in an ion-exchange membrane caustic soda project yesterday; I got to know instrument automation design engineers as well as the plant operators in charge of instruments. If you need anything, please call 15255081999
This is a complete control system design, along with interlocks; if it’s not implemented properly, there can be liability issues as well. Generally, one doesn’t dare to do it casually.