Help needed

No one responding? It seems that the problem indeed exists. Perhaps many people, like me, have been working on instrument and new project management for years, but have never really thought carefully about what the proper way to carry out on-site instrument calibration should be. Choosing to act on one’s own or taking no action at all (waiting until problems arise after the system starts operating) is the norm. It’s unclear who is responsible, from the construction company to the owner. Perhaps some people think it’s pointless to dwell on such details; as long as the instruments are working properly, that’s what matters, as there are many ways to reach Rome. I also think it would be better if the regulations for 3503 and 3543 provided more practical guidance, rather than just offering simple tables.

1. Reference can be made to GB50093-2013 Code for Construction and Quality Acceptance of Automatic Instrumentation Projects. 2. Add 4~20mA; the simulation and wiring calibration are the same. Toxic (flammable) gas detectors must be tested before installation. Purchase and installation are possible only after passing the inspection

Question 1: Are there any specific implementation guidelines for the calibration of primary instruments and circuits? In other words, it guides the on-site workers on how to complete the commissioning of on-site instruments (individual units) in a thorough and effective manner. Question 2: How can a toxic (flammable) gas detector be calibrated without a calibration gas? Just add 4~20mA for simulation (is it the same principle as calibrating the wires?) ). As a construction professional, here’s my answer: 1. GB50093-2013 specifies clear requirements for individual inspections and joint inspections. Additionally, during the bidding process, there is a document called the technical proposal, which includes construction plans for various specialties. During actual construction (and certainly before it begins), both the client and the supervisor will request construction plans specific to the instrumentation specialty; in some cases, strict requirements exist that call for construction plans tailored to each individual project element. Also, I’m not clear on what you mean by on-site instrument calibration (for individual units). Instrument calibration includes individual calibration, circuit joint calibration, and interlock testing. \"Single-site calibration\" refers to the process in which, after the gauge passes the factory inspection, it is transported to the site where it is used by the construction party. Calibration is carried out in a calibration room using testing equipment that has been inspected by quality and technical supervision agencies (such as Fluke 744, Conest pressure modules, etc.), in order to determine whether the gauge meets the standards set at the time of factory exit and to detect any errors caused during transportation. This cost is already included in the installation fee for the instrumentation equipment. \"Circuit simulation testing\" involves the process of carrying out calibration according to the circuit diagram, once the cabinets are powered on and all the necessary gas supply cables are in place. For example, in the regulation loop simulation test: a simulated signal is applied at the detection point, and then it is observed whether the actuator can operate as per the design requirements. (Of course, in practice, people are usually lazy and just use the DCS to monitor the 4 points to ensure that the valves move to the correct position – that’s sufficient.) Interlocking is mainly carried out in coordination with electrical systems. In summary, there are no guidelines that tell on-site workers how to carry out instrument calibration properly and effectively (otherwise, what would those forms in the handover documents be for?). Therefore, I guess you are dealing with fake construction teams and fake supervisors. 2. The situation with toxic (flammable) gas detectors is rather special; we have never carried out any calibration for them before. There are two scenarios I’ve encountered so far: a) The client requests that the manufacturer provide calibration gases and carry out calibration on-site at the time of purchase, and in such cases, our construction team only needs to ensure that the wiring is in order. b. The owner sends the detector to the local Quality and Technical Supervision Bureau for testing; no calibration gas from the manufacturer is required. Once it’s returned, we install it, and the Quality and Technical Supervision Bureau issues a test report. We then attach this report to the completion documents for the inspection by the relevant authorities such as the Quality Supervision Station or the petrochemical industry agencies. That’s all that’s needed. That’s all. . . . . . . . . . . . . . . .

I think the workers on site did everything right; the gauge was new and of good quality. After checking the wires, the readings on the screen became correct. What other problems could there be then? For gas detection, it involves calibrating the sensor wires; calibration is mandatory. You take the wires apart for calibration, and once they pass the test, you put them back in place. All you need to do is ensure that the wires are in good condition – any other issues are not your responsibility, and there shouldn’t be any problems anyway

Work when sober, read when confused, sleep when angry, and reflect when alone； Be a happy person: read, travel, work hard, and take care of your body and mind.

Could you provide me with these construction plans for reference?

It’s on Baidu; they even put my name there

President Zhao~~~;P Thank you so much, I’ll take a look first. :handshake

First of all, thank you! :Handshake 1: For single-check during debugging, we complete this before the installation of the instrument to ensure it meets the technical requirements. The on-site instruments are installed by the construction party. There are also corresponding handover document forms. 2. Regarding the loop calibration during debugging, what is done now is to apply signals at the field side using a signal generator after powering on the DCS; in essence, it’s still line calibration (no difference from before powering on the wiring). In my opinion, it is necessary to check whether the field transmitter is zeroed and whether the temperature is at the ambient temperature, that is, whether it is displayed within a reasonable range. But there is a lack of practical guidelines on how to do it. For example, the upper and lower flanges of the level transmitter should be loosened to ensure they are not under stress, before zeroing it. Most construction companies just move on without making any adjustments; they wait until later, when materials are used in the production process and discrepancies are detected, to try again. It’s really frustrating. There are no prescribed actions; even if you tell him, he won’t listen – it’s all up to him to choose what to do. 3. For joint calibration, it is of course carried out based on single-device and loop verification, and there are currently not many issues. It’s mostly the owners themselves. 4. With toxic gas detection, there is this issue: for each circuit, the construction party considers the verification complete once power is supplied to that circuit and it is confirmed to be consistent with the actual situation on site. We raised objections, and the other party was also frustrated, not knowing what to do. 5. Specifications for the construction and quality inspection of automated instrument projects – we have such specifications, and we have been using them since we started working on projects. However, we still find them too general (specifications are easy to understand when they are general; if they are too specific, they cease to be specifications). It would be better if there were relatively specific guidelines that could guide practical operations and that were widely recognized.

First of all, I’m not President Zhao; I’m just a construction worker. If I were President Zhao, I wouldn’t be here working. To answer your question: First, there’s no problem with single-unit testing, but as a construction worker, I can tell you that it’s mostly just a formality. While generally the results won’t show any major issues, problems that do arise from single-unit testing can be very troublesome. Secondly, loop calibration is not simply about checking the wires; it involves measuring the errors in the entire system, including the DCS, the wiring, and the instruments. The proper approach is to apply a signal at the transmitter that has a control relationship with the control valve – some experts suggest using an actual pressure signal for this purpose, but we usually use analog signals to determine whether the control valve operates as intended. Of course, as the construction party, we basically just go through the motions – we send signals to the control room to see if the valves operate properly; that’s good enough. It’s slightly better than just checking the wiring. Can it really be called migration if no flanges are provided for double-flange migration? It’s clear that the construction party doesn’t have anyone competent enough to handle this. Thirdly, joint efficiency – this is certainly not included in the construction party’s contract; at most, they will offer compensation and cooperation to the owner. Fourth, regarding toxic gas detection, there are currently two methods I’m aware of: the first is to send the samples to the local or external quality and technical supervision authorities for testing, and the second is for the manufacturer to provide standard gases for on-site calibration. Fifthly, GB50093 is the minimum standard for guiding and supervising the construction quality of contractors; the general construction process can be found within it. Lastly, regarding the installation of instruments, it seems to me that the pace of innovation in this area has been extremely fast over the years I’ve been working (compared to electrical installation work). The advent of intelligent instruments has made it much easier for construction companies to carry out their tasks. However, as a member of a construction team, I feel that it’s more important to have a broader range of skills rather than focusing on just one specific area. After all, our job involves using instruments as auxiliary tools; the main focus should always be on the manufacturing processes. In production units, it’s necessary to follow the instructions of those who are experts in these processes – we just need to meet their requirements. For single-unit combined efficiency, it’s sufficient to ensure that the process can operate.