说明：  文档名称：伟思D20_RTU通讯协议 作用及功能：该文档是购买D20型rtu后销售方发给的技术文档，D20rtu为雨量采集器。
(Document Name: Visto D20_RTU protocol Role and Function: This document is issued by the seller after the purchase of technical documentation D20 type rtu, D20rtu the rain collector.)