Issues regarding the calibration of instruments for newly launched projects
Thread Content
It is now in the debugging phase, although the three inspections and four determinations have not yet been completed. For various reasons, the electrical and instrumentation installation process was chaotic; no individual testing was carried out before installing the instruments. Now, after wiring, signals are sent directly on-site to conduct loop tests. Is actual calibration required for voltage transformers? Do level gauges such as differential pressure, magnetostrictive, and radar types need to be actually calibrated? Are actual flow calibrations required for integrated balance, wedge, and rotameter types? There should be no instruments at the site that require inspection. How are on-site indicator instruments calibrated? How can one determine whether the selected transmitters and on-site indicator instruments are accurate? What is the magnitude of the error? I don’t know which standard to consult; I only know that integrated orifice plates do not require calibration. Can production be started right after the circuit testing is completed? Since I’m not entirely confident in domestic instruments, I hope experts with extensive project experience can offer guidance
New instruments must be calibrated. For those that are smaller and simpler, we usually handle the calibration ourselves, but for larger instruments, the manufacturer must carry out the calibration on-site together with our technical staff until they operate properly and meet the required standards.
On-site pressure gauges, bimetallic thermometers, pressure (differential pressure) transmitters, combustible gas detectors, control valves, switch valves, etc. must be individually calibrated before installation. Floats, glass plate level gauges, etc. can be calibrated by filling with water after installation. Mass flow meters can be calibrated at the designated metrological verification institutions. For devices such as integrated balance, wedge-type, rotameter, radar, ultrasonic, and steel belt level gauges that do not have calibration capabilities, the manufacturer’s calibration certificate shall be taken as the reference.
If there is no time or means available, as a minimum requirement, check by powering it on or using measuring instruments: 1. For pressure transducers and differential pressure sensors, verify that the reading is 0 when there is no pressure; pressing the pressure sensing port of the transducer should result in a change in the reading. In the case of devices installed at simple connections such as water pipe interfaces, check whether the transducer displays a numerical value. 2. Level gauges such as magnetostrictive and radar types do not require actual calibration, but it is necessary to simulate level changes to check whether the measurement range of the level gauge is appropriate and whether there are any level variations. Is the installation location appropriate? 3. Integrated balance, wedge, and rotor flowmeters do not require calibration with actual fluid; it is sufficient to confirm that they are installed correctly. 4. Signal verification for on-site indicator instruments. The same goes for remote transmission – generally only the critical items are checked, though you can check them all as well. Judging from the questions you’re asking, you lack experience, so the workload must be quite heavy. An experienced person can do it in 1 day; it’s possible you won’t be able to do it even in 10 days: lol
Generally, for a single device, the range is adjusted according to the manufacturer’s settings； Please have the manufacturer come to verify the complete set of equipment.
The regulations specify that instruments must be inspected, calibrated, and tested before installation and use. Calibration and testing should be carried out indoors. For loop tests, the standard signal of the variable under test should be simulated at the signal input terminal, rather than setting the value directly using a manual operator. The practices you mentioned are completely in violation of standards and regulations, and should be corrected. For details, please refer to Part 12 of the specifications.