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RS485扩展器
rs485电缆制作
Introduction to RS485 RS232 , RS422 , RS423 and RS485 are serial communication methods for computers and devices. RS232 is without doubt the best known interface, because this serial interface is implemented on almost all computers available today. But some of the other interfaces are certainly interesting because they can be used in situations where RS232 is not appropriate. We will conce
基于RS485通讯的数据服务器设计
基于RS485通讯的数据服务器设计
本文主要介绍了数据服务器的硬件系统设计及软件系统设计。本数据服务器是上位机与现场仪表进行数据交换的桥梁 ,上下都采用RS4 85接口。数据服务器通过人为设定的采样周期对现场仪表进行采样 ,读回数据并以一定的格式进行存储。数据服务器根据上位机发来的命令进行相应的操作 ,并返回数据给上位机 ,包括读取当前时间、所连仪表起始地址、单台或全部仪表的当前数据、历史数据。