超声波换能器作为一种实用的检测手段，能实现声波所携带的信息和电能之间转换。它的性能优良，价格低廉，操作方便，易于调试，因此在工农业生产中发挥着重要的作用。但目前换能器驱动电路的发射频率多为40 kHz，本文针对1 MHz的超声波换能器电路进行了设计，主要介绍了它的发射驱动电路和接收驱动电路的设计方案，并对它们的功能进行了详细地说明。最后搭建实验平台，并对电路的输入、输出模块进行了测试。实验结果表明，换能器电路运行良好，可以为超声波高精度测量领域的应用提供参考。As a practical meanS of detection, ultrasonic transducer can realize the conversion between theinformation carried by sound wave and electric energy.It has the advantages of excellent performance,low cost, convenient operation and debugging, so plays an important role in industrial and agriculturalproduction.However, the transmitting frequency of the driving circuit for most transducer is 40 kHz.Thecircuit of 1 MHz ultrasonic transducer is designed In this paper. It mainly introduces the emissive drivingcircuit and the receiving circuit design and the detailed function of them. Finally, the experimentalplatform is built, and the circuit of input and output were tested. Experiments show that the transducer＇ s...
上传时间： 2022-04-28
上传用户：yb9018
If register should be written or read.This value is passed to the calback functions which support either reading or writing register values. Writing meanS that the application registers should be updated and reading meanS that the modbus protocol stack needs to know the current register values.See also: eMBRegHoldingCB(), eMBRegCoilsCB(), eMBRegDiscreteCB() and eMBReglnputCB().Enumeration values: MB_REG_READ Read register values and pass to protocol stack.MB_REG_WRITE Update register values.Note: Note all ports implement this function.A port which wants to get an callback must define the macro MB_PORT_HAS_CLOSE to 1.Returns: If the resources where released it return eMBErrorCode:: MB_ENOERR. If the protocol stack is not in the disabled state it returns eMBErrorCode:: MB_EILLSTATE.Examples: LINUX/demo.c, MCF5235TCP/demo.c, STR71XTCP/demo.c, WIN32/demo. cpp, and WIN32TCP/demo. cpp.his function disables processing of Modbus frames.Returns: If the protocol stack has been disabled
标签： FreeModbus
上传时间： 2022-05-31
上传用户：hbsun
Abstract: A sliding mode observer and fractional-order phase-locked loop (FO-PLL) method is proposed for the sensorless speed control of a permanent magnet synchronous motor (PMSM).The saturation function is adopted in order to reduce the chattering phenomenon caused by the sliding mode observer. In this proposed FO-PLL, method, a regulable fractional order r is involved, which meanS that the FO-PLL provides an extra degree of freedom. In fact, the conventional phase-locked loop (PLL) applied in sensorless PMSM control can be seen as a special case of the proposed FO-PLL. By selecting a proper fractional order r a better performance may be achieved. The computer simulation results demonstrate the effectiveness of the proposed method.Key words: fractional calculus; fractional order phase-locked loop; sensorless control; sliding mode observer; permanent magnet synchronous motor; speed controll
上传时间： 2022-06-18
上传用户：pagedown
