Tech Field:
This utility model relates to a hydrological data measurement system, particularly to a hydrological cableway measurement system.
Background Technology:
Currently, in China's hydrological cableway measurements, the transmission of multiple signals such as flow rate, water surface, and riverbed through cableway loops remains unresolved, severely impacting the development of our country's hydrological cableway measurement technology. Up to now, there are three forms of cableway signal transmission: wired transmission, radio wave transmission, and "wireless" transmission.
1. The wired transmission sensors transmit signals back to the cableway control room using core steel wire ropes or the main cable and the deviation cable on the deviation cable track. The key to this transmission method is to select high-quality core steel wire ropes. Proper insulation between wires during cableway installation ensures minimal signal attenuation and strong anti-interference capability. However, due to the numerous connections, this method is particularly prone to corrosion and rust, which can lead to the inability to transmit cableway signals and a shorter lifespan.
2. The transmission sensors are not connected to any indoor receiving device; they rely solely on airborne radio waves to receive sensor signals. Generally, an underwater signal transmitter should be installed. This device receives signals from underwater sensors, modulates them into radio waves, and transmits them through the portion of the lifting rope above the water surface. After being transmitted through the air, they are received by a shore-based receiver, demodulated to restore them into digital signals, and then recorded and displayed. Currently, two types of modulation are in use: amplitude modulation and frequency modulation. The two major challenges for successful application of this method are the high power consumption of the underwater signal transmitter and the significant transmission loss of radio waves in water.
3. "Wireless" transmission, which is not truly wireless in the conventional sense, refers to a specific type of transmission that utilizes the main cableway rope and the water's surface to form a transmission loop. The use of "wireless" transmission is a common method for signal transmission in hydrological cableways and survey vessels.
Utilizing a cableway for "wireless" transmission of direct current signals is an ideal method; however, in practical use, it is only suitable for transmitting a single signal and is prone to damage due to the high current flow through the flow meter, which easily burns out the signal switches. The actual cableway signals required include various signals such as flow rate, water surface, and riverbed, and there are also many interference signals on the cableway, making the "wireless" transmission of direct current signals a highly complex situation.
