【JST-054】Automation and Instrumentation One-on-one Q&A Office
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This post was last edited by Firefly on 2015-4-10 08:37. In order to better share knowledge and skills with you, I would like to apply for a "technical discussant". I also take it as a challenge to myself. According to the requirements, a special Q&A post is set up. My specialty: petrochemical automation and instrumentation work experience: With 27 years of petrochemical automation and instrumentation design and engineering management, I will try my best to answer any questions you may have! (Note: 1) This post mainly talks about issues related to petrochemical process automation and instrumentation, to communicate with each other and improve together. 2 h: u' a8 q# Z% l/ g- T 2) This post is exclusively for one-to-one discussion between the person seeking help and myself. Other friends are also welcome to participate in the discussion. If you are not satisfied with the reply, please post a new topic in the control system and instrument communication area. Thank you for your cooperation! 3) Due to work, sometimes I may not be able to reply in time, sorry for that.
In the interlocking of a single electrolytic cell in the electrolysis unit, one of the conditions is: IF Electrolyzer load is decreased coming from >1kA AND less than 0.2kA THEN Shut down single electrolyzer meaning: When the electrolytic cell current drops from more than 1kA to less than 0.2kA, the electrolytic cell stops.: How to draw interlocking logic diagram? Thanks
Congratulations on being the first person to ask a question. I don't know much about the electrolysis device process, so I used an AND gate according to the meaning of the question, as shown in the attached picture. What makes people a little confused is that: Electrolyzer load is decreased coming from >1kA and less than 0.2kA. Logically, there is only one condition, that is, Electrolyzer load is less than 0.2kA.
Hello, landlord! I also have a question, also about chaining. How to express it on the PID diagram? The control equipment is two variable frequency pumps, one for use and one for backup, 4 shut-off valves, and 2 emptying valves. The leaching slurry pumping control needs to realize the functions: 1. Control the start, stop and operating speed of the slurry pump to maintain the stability of the liquid level in the leaching intermediate tank. 2. When an abnormality occurs in the system (overflow of the slurry pump, sudden change in the liquid level of the slurry tank, etc.), the running slurry pump and the backup slurry pump will automatically switch. 3. System operating status and alarm output. Parts that need to be linked: Leaching intermediate tank liquid level gauge, variable frequency pump, gate valve in front of the pump, gate valve after the pump, and drain valve. I am a newbie, I hope you can give me some advice!
Hello, according to the definition of PID, PID cannot and does not need to express specific logical relationships. Usually the representation method on PID is: according to the interlocking legend on PID, use a dotted line to connect the legend and related parameters, as shown in the attached figure. The specific logical relationship must be expressed in the logic diagram.
Hello, sir, how can split-range control be implemented in DCS configuration?
How to configure split-range control in DCS is in the I/O configuration. It’s very simple. I hope it can help you.
I wonder if, instead of asking just a small piece of logic, I can free up space for everyone to see questions and answers that are truly informative.
Upstairs, I feel that the DCS you have used is a relatively powerful brand, or a foreign system. I personally feel that this is too simplistic for your interpretation of split-range control.
Sir, let me ask a question: “How to implement sub-process control using FBD function block diagram? Is the so-called dividing process what many textbooks say?: Divide a control object signal into two segments (to give a simple example), and then use signal judgment and other means to distinguish the respective signal segments, and the two PIDs respectively output and control the respective signal segments, right?
This post was last edited by san4 on 2012-7-20 14:56 Thank you for your answer. I think it is not possible for the current to appear "greater than 1" and "less than 0.2" at the same time. The problem has been solved in another post, http://bbs.hcbbs.com/thread-1018780-1-1.html