On the issue of long-distance transmission of flowmeter signals related to trade settlement (updated)
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This post was last edited by jiaguoyun on 2016-4-1 at 14:28. There is a project involving external steam supply (medium-pressure steam; trade settlement is required). The flow meter is installed at the factory boundary, at a considerable distance from the cabinet room (about 580 meters). It has been initially determined that when the flow reaches a certain value N, a certain electric ball valve should be shut off via interlock. For signal transmission, there are currently two options: 1. The traditional approach, which involves running all signal cables to the nearest cabinet room (about 580 meters), with temperature and pressure compensation as well as interlocked shut-off valves implemented within the DCS. 2. Install a flow integrator on-site (the 220VAC power supply comes from a cabinet room 580 meters away); the integrator includes internal temperature and pressure compensation. It outputs DO signals for alarm purposes to enable the DCS to activate interlock valves. Fiber optics are used to connect the integrator to the DCS, with Modbus communication being used to transmit real-time data. 3. Bus-type instruments are used for flow rate, pressure, and temperature. Transfer to DCS to interlock and shut off the valve. If it were you, how would you choose? Are there any other better ways? @HEJIYUER @budaoweng123 ………………………………………………………………………………………………………………………………………… New questions added for everyone to discuss: 1. According to the process requirements, electric actuators should be used for these cut-off valves; I chose electric ball valves. However, the process specifications state that this was because the valves were initially installed near the perimeter wall where there was no air supply. Later, these valves were moved to the plant area. Would it be better to use pneumatic ball valves instead? 2. Ball valves have good shut-off performance, but they open too quickly; for steam media, could the presence of condensate in the pipes downstream cause an accident? However, if ball valves are not chosen, the leakage rate of other types of valves may be high~~ 3. Of course, these concerns can also be avoided by specifying operating procedures and precautions in the operation guidelines, but how should an optimized design approach be considered?
This post was last edited by budaoweng123 on 2016-3-28 at 14:43 :lol Thank you, beautiful lady, for thinking so highly of me. Do you plan to use orifice plates or vortex street sensors? I choose Option 1. Just in terms of distance, 580 meters is not really far for a 4-20Ma analog signal; if you want to be safe, a 1.5 total screen splitting cable will suffice. For Option 2, it is actually possible to choose instruments with a MODBUS RTU communication interface; however, for distances of up to 1 kilometer, optical cables are not necessary. As a precaution, Siemens Profibus communication cables of type 6XV1 830-0EH10 can be used. Compared to the A/D & D/A conversion errors of analog signals, MODBUS offers higher precision, and it is also possible to directly read the cumulative value displayed on the meter. :Lol, I wish this beautiful woman to remain as sexy and beautiful as Kim Kardashian forever.
I choose Option 2; it’s necessary to make some changes – using 485 communication between the calculator and the DCS will suffice, but this will result in a slightly higher volume of work. During on-site debugging, it is more convenient as it is done at the site.
Choosing Option 1 is completely fine
It seems you are the seller, right? If it were me, I would choose option two. After all, the loss is minimal.
This post was last edited by zxb1990 on 2016-3-28 at 22:36. Option 1 will do; the transmission distance for current signals is within one kilometer, and it has fairly strong resistance to interference
Mass flow meters for medium-pressure steam are of a higher specification. Vortex streets also have pulses.
It is still quite common to use vortex flowmeters for measuring steam, and the results are good
I chose the vortex flow meter, but a colleague working on a similar project opted for an orifice plate. I think that devices like orifice plates require a lot of effort for heating and insulation, involve significant maintenance needs, and have a higher failure rate due to environmental factors compared to vortex flow meters. Although the overall cost of imported vortex flow meters is slightly higher than that of orifice plates, I still think this is the better choice! (It seems that Kardashian still attracts a lot of attention{:3_67:}). Wishing him happiness!
What is the subject of the \"loss\" you are referring to?