Help, how to transmit the gauge signal at approximately 3200 meters! !
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For a long-distance pipeline, a mass flow meter and a pneumatic shut-off valve need to be installed for quantitative interlocking. The installation site is approximately 3,200 meters away from the cabinet room. Can a 4-20MA signal be connected directly? Can a cut-off valve be used over such a long distance? Are there any other good solutions? Seeking advice
How to achieve it, what needs to be added
For 2.5 square millimeter twisted pair, the resistance per kilometer does not exceed 10 ohms; over 3 kilometers it is 30 ohms. At a current of 20 mA at full scale, the voltage drop is only 0.6V, so it’s easy to transmit signals over distances of 2 or 3 kilometers.
For 2.5 square millimeter twisted pair, the resistance per kilometer does not exceed 10 ohms; over 3 kilometers it is 30 ohms. At a current of 20 mA at full scale, the voltage drop is only 0.6V, so it’s easy to transmit signals over distances of 2 or 3 kilometers.
I’ve also done the calculations, and indeed 3 kilometers is feasible as well. I’m just not sure if there will be any issues with the actual results, since it involves trade measurements.
If it’s just a 4–20mA signal, there’s no major issue; but if solenoid valves are involved, it might not work.
For analog signal transmission, using a cable with a thicker gauge poses no problem. For standard four-wire instruments, the signal load should be fine. For the control signal of the valve, it can be tested by adjusting the voltage; if the distance is large, the voltage can be increased slightly.
I plan to use a batch controller; it seems there’s a 220V switch available
Wireless is more troublesome; it’s similar to a phone, requiring you to purchase something from a telecommunications company