What are the common reasons why the temperature measurement point on the DCS operation screen turns white?
(1) The clamp safety barrier is not powered or faulty
(2) The site is not wired or the wiring is wrong
(3) The measured temperature is out of range
There is a pressure transmitter, which is used to measure the pressure inside the chimney, how to judge whether the pressure transmitter is good or bad, what is its resistance value, and how to carry out zero point correction.
- The easiest way to do this on the spot is:
Usually look at the zero pressure input ,see if the output is at 4AM,and whether the changes with the pressure change. The internal resistance parameter of the instrument is used to calculate the voltage drop of the equipment, and the internal resistance is different under different pressures. And the internal resistance of many manufacturers is the highest upper limit (conservative parameters), and often the actual products will not have this high internal resistance. If there is a condition, it is still necessary to suppress and measure the output!
During the winter start-up period, the process personnel said that there was a differential pressure transmitter indicating a large difference from the actual situation of the process, and it was required to be treated. Please describe in detail the overall process of dealing with the fault. (Should include: communication, interlocking, anti-freezing, security, records and other related content)
1. After detailed communication with the process personnel, confirm the instrument number and confirm the operating conditions. Fill out the work ticket and get ready to start working.
2. For the instruments involved in the interlocking, after filling in the interlocking return form before processing, the interlock of the response should be released in the DCS and ESD.
3. Check the heating situation after arriving at the site, if it is frozen, check the heating pipeline first, and then purge the heating and pressure pipes with low-pressure steam. Check the cause of freezing, if the steam tracing pressure is not enough or the heating steam stops, contact the process immediately to deal with the steam tracing.
4. If it is not the cause of freezing, check whether the root of the transmitter can discharge the liquid, so as to judge whether the pressure pipe is on. If not, it should be treated by sewage or purging.
5. It is possible to discharge toxic and harmful process gases when discharging sewage, and check the heat tracing to prevent scalding.
6. After processing, the insulation and on-site sanitation of all the tables should be treated, and the process personnel should be required to pay more attention to the display of the instrument and sign the work contact sheet.
Post time: Apr-23-2024