这部分定义了应用层报文(APDU)的格式。这里，主站被定义为发送请求报文的站，而外站则为从属设备。被请求回送报文的RTU 或智能终端(IEDs)是-definition of this part of the application layer packet (APDU) format. Here, the main points are defined as the request to send the text to the station reported, except for stations affiliated equipment. The request was reportedly sent back to the text of the RTU or intelligent terminals (converter)