如何RS-232传输距离？解决RS232传输距离只有15米的限制？

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inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">RS232与RS485在实际项目中都有应用，对于rs485很多朋友可能比较了解，那么对于RS232呢？我们可能只记得他只能传输15米的距离了，那么我们今天来看下，如何增加RS232的传输距离。
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">我们先来对比下RS232与RS485的区别。
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">

inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">1、RS232：portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">RS232传输距离有限，最大传输距离标准值为portant; word-wrap: break-word !important;">15米，且只能点对点通讯，portant; word-wrap: break-word !important;">最大传输速率最大为20kB/s。
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">2、RS485：portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">RS485最大portant; word-wrap: break-word !important;">传输距离为1219米。最大传输速率为10Mbps，在100Kb/S的传输速率下，才可以达到最大的通信距离。
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">
inkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; background-color: rgb(255, 255, 255); box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; word-wrap: break-word !important; color: rgb(62, 62, 62); font-family: Optima-Regular, PingFangTC-light; font-size: 15px; letter-spacing: 0.544px; text-align: start; text-indent: 34px; widows: 1;">采用阻抗匹配portant; word-wrap: break-word !important;">、低衰减的专用电缆可以达到1800米！超过1200米，可加portant; word-wrap: break-word !important;">中继器（最多8只），这样传输距离接近10Km。
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看到这里，你可能会问，如何很多系统很多都是232的，距离问题怎么解决？主要有这些解决的方法。

一提到RS-232串口的长距离传输，人们总是想起RS-485或RS-422。RS-485确实是可以用2根线实现延长1200米的长距离传输，但是其实还有更多的方式也可以延长RS-232的距离，比如光纤、电流环、CAN、增强器等。波仕的零延时切换技术保证采用以上任何方式都能够在RS-232方式下编写的程序无需更改便可在RS-232方式下运行，确保适合现有的操作软件和接口硬件，转换器波特率自动适应。
1、 RS-232/RS-485转换器、优点是只要2根信号线，可以无源，支持多机通信，缺点是半双工不能够同时收发。
2、 RS-232/RS-422转换器。优点是全双工能够同时收发，可以无源，也支持多机通信。缺点是要4根信号线，外加GND就是5根。
3、 RS232光隔远程收发器，采用电流环。优点是延长的同时还实现了双方RS-232的相互隔离而且无源，缺点是不支持多机通信，只能够1对1，需要布4根线，无需GND。改进的冗余型产品Y232A2也只能够实现1对2通信。
4、 RS-232光纤转换器，分有源OPT485系列和无源OPT232系列，优点是彻底隔离电磁干扰信号且传输非常稳定，缺点在于成本，主要是光纤布线工程的成本。
5、 CAN232G系列超远程驱动器，采用CAN电平传输，只要2根信号线可以传5～10Km，也支持多机通信。缺点相对于无源RS-485转换器而言在于必须外接电源。
6、 直接的RS-232增强器，EX232采用了一种增强型的RS-232口标准，可以直接传输500米，需要外接电源。由于RS-232本身不支持多机通信所以EX232也不支持多机通信。EX232支持继续接RS485转换器。
7、RS-232转以太网转换器，实现RS232到RJ45以太网的透明传输。虽然ETH232的距离只是从RS232口的最远15米增加到RJ45以太网的最远150米并不明显，但是主要优势在于它可以使具有RS232串口的设备接入以太网（TCP/IP协议）的功能，把分散的串行设备、主机通过网络集中管理，而且以太网转光纤也是非常方便的。在进行了IP地址、波特率等参数设置完毕后的ETH232就相等于是透明传输，所以使用时不必担心通信软件问题。

这里有个问题，就是控制系统大多用485传输，如果有的设备只有232的话，距离远了可以用232/485，转换了之后传输再转换回来吗？
答案肯定的，使用232/485转换器后，再在远端将其转换为RS-232串口就行。