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目录
第 1 章 RS-485 选型及应用指南.........................................................................1
RS-232/422/485 标准...............................................................................................1
RS-232 标准.....................................................................................................2
RS-422/485 标准..............................................................................................2
RS-485/RS-422 芯片................................................................................................5
增强型低功耗半双工 RS-485 收发器-SP481E/SP485E..............................7
1/10 单位负载 RS-485 收发器-SP481R/SP485R .....................................10
+ 低功耗半双工 RS-485 收发器-SP3481/SP3485..............................13
增强型低功耗全双工 RS-422 收发器-SP490E/SP491E............................15
+ 低功耗全双工 RS-422 收发器-SP3490/SP3491..............................20
RS-485 接口电路...................................................................................................22
基本 RS-485 电路...........................................................................................22
隔离 RS-485 电路...........................................................................................23
上电抑制电路.................................................................................................24
RS-485 自动换向电路....................................................................................24
RS-485 通讯协议...................................................................................................25
ModBus 协议(RTU 模式)...............................................................................25
多功能电能表通讯规约(DL/T645-1997) ......................................................27
RS-485 程序设计........................................................
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