I基于 RS485 的变送器通信模块设计摘 要：以往的变送器大多是模拟量输出，模拟量因受电源的限制，其数据表达是有限的且抗干扰能力弱。总线技术的发展使得变送器的数字量输出成为一大发展趋势，采用数字量输出的变送器数据表达比模拟量更精确，且抗干扰能力更强。RS485 总线支持多点数据通信方式，可对共模干扰进行抑制。总线的信号收发装置具有良好的灵敏度，可检测的电压范围较广，因此传输信号可在较远的距离上得到有效恢复。基于此可知 RS485 总线在工程现场得到了大量应用。因此研究设计基于 RS485 的变送器通信模块，使得传统变送器的数字量传输成为可能，具有较强的实用价值。关键词：变送器、RS485 总线、通信模块IIDesign of transmitter communication module based on RS485Undergraduate：CaozhenSupervisor:Liao MeiyingAbstract: In the past, most of the transmitters were analog outputs. The analog outputs were limited by the power supply, so the data expression was limited and the anti-interference ability was weak. The development of bus technology makes the digital output of the transmitter become a big development trend. The data expression of the transmitter using digital output is more accurate than the analog one, and the anti-interference ability is stronger.RS485 bus USES half-duplex communication, supports multi-point data communication, adopts balanced transmission and differential reception, and can effectively suppress common mode interference. In addition, the bus transceiver has high sensitivity and can detect voltage as low as 200mv, so the transmission signal can be recovered beyond kilometers. Because of these advantages, RS485 bus has been widely used in engineering field. Therefore, the research and design of the transmitter communication module based on RS485 makes the digital transmission of the traditional transmitter possible and has strong practical value.Key words: transmitter, RS485 bus, communication moduleI...
