Research And Application On AFS Automatic System Of Box-hanging Hydrometric Cableway

As the most widely used and effective flow measuring equipment, the hydrometric cableway adopted in our country is lag in technology at present.Including sounding and velocity measuring, many key steps require human intervention. The method used to signal acquisition and transmission is also backward. As a result, the flow measuring is extremely ineffective.To solve the above issues, combining the characteristics of box-hanging cableway and suspended rod measuring, the key technologies were studied.Then the automatic hydrometric cableway of type AFS was designed and developed.The newly designed box-hanging measuring platform could complete the automatic connection of all the steps in hydrological flow measuring. The platform and the control room were connected by the wireless data transmission module, then the measuring platform realized unmanned operation.The control unit was consisted of master control unit, horizontal control unit and platform control unit. The control system adopted IPC/PLC-Master/Slave two level structure, the platform and the control room exchanged information by Modbus communication protocol. As the masterdevice, the IPC in control room was equipped with flow measurement software used to dispatch the whole system and complete human-computer interaction.The PLC of horizontal and the platform could be not only used as slave devices to receive master instruction, but also used as field control stations to control the operating equipment and measuring process of the cableway. Then the system has a dual mode operation of remote and field.The velocity signal and water surface signal were screened out by LM339,the underwater signal was judged by tumbler weightlessness detection device.After eliminating by hardware and software, isolating by optical, the signals were transmitted to PLC through Wireless MCU CC1110, then sounding and velocity measuring could be automatically completed.The standard communication interface was adopted, and the programming interface for the sub modules was provided by defining the communication between IPC and PLC. As a result, the system realized modularization, and the whole system’s configuration was flexible and highly versatile.The application of the whole system has changed the original flow measuring model of hydrologic station, it not only reduced manpower, but also improved the efficiency of flow measuring greatly. So it has a wide range of application prospects in every hydrological station.