Since RS-485 communication port plays a minor role in operation of electric energy meter,the original requirements and functions requested for each communication port of the meter is retrieved,the features of communication port,especially the infrared communication are researched,and the feasibility of using infrared communication port to implement all the functions of RS-485 ports is investigated. Infrared port is space open port,multiple pairs of infrared communication ports may interfere to each other when they communicate simultaneously;while RS -485 communication port is wired communication, the problem doesn' t exist. In order to solve the problem that several infrared communication ports interfere to each other when they communicate at the same time, and they can ' t communicate when the signal intensity is too strong, the method of inserting attenuating media between two infrared communication ports is put forward. In this way, the infrared light is attenuated to the magnitude that two infrared communication ports can communicate each other,while the diffused light is attenuated to be ignored. In addition, the influence to checking meter process because of slower infrared communicate rate, and how to avoid illegal checking meter are researched. The results show that in most cases, RS -485 communication port is not necessary in fact;removing RS-485 communication port from carrier line of the meter can reduce costs and energy consumption without decreasing its functions.%针对电能表运行中RS-485通信端口作用有限的问题,追溯了电能表各通信端口要求的历史来源和各通信端口的功能;研究了电能表的通信端口,特别是红外通信的特点;探讨了使用红外通信端口实现RS-485端口所有功能的可行性.红外端口为空间开放端口,多对红外端口同时通信时容易产生干涉;而RS-485端口为有线通信,则不存在干涉问题.针对多个红外通信通道同时通信容易互相干涉,且红外信号太强无法通信的特点,提出在2个红外通信端口间增加衰减介质的方法,使得2个红外端口之间信号衰减到能够正常通信的强度,且散射光衰减到可以忽略的程度.同时,研究了红外端口通信速率慢对校表效率的影响及防止非法校表的操作.研究结果表明,在大多数场合下,RS-485通道其实并不是必要的,去除载波电能表RS-485通道可以有效降低成本和功耗,同时保持载波电能表的功能.
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