为什么485总线一定要是手牵手方式连接...

不可以并接吗？

可以呀！

<p>只不过会有干扰而已,并接的话可能会出现串包啊,信号干扰啊,导致系统出错的概率会很大.</p>

<p>这个要说原理就深了，485是通讯是弱电控制常用的国际标准，遵循就好了。</p><p>但要是只有两个设备把它并起来，不一定就完全不能用，但肯定通讯不好。</p>

<p><span style="FONT-SIZE: 13.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ascii-font-family: sans-serif; mso-hansi-font-family: sans-serif; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">其他结构会产生反射信号，从而影响到</span><span lang="EN-US" style="FONT-SIZE: 13.5pt; FONT-FAMILY: sans-serif; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 13.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ascii-font-family: sans-serif; mso-hansi-font-family: sans-serif; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">通信。总线到每个终端设备的分支线长度应尽量短，一般不要超出</span><chmetcnv wst="on" unitname="米" sourcevalue="5" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 13.5pt; FONT-FAMILY: sans-serif; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">5</span><span style="FONT-SIZE: 13.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ascii-font-family: sans-serif; mso-hansi-font-family: sans-serif; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">米</span></chmetcnv><span style="FONT-SIZE: 13.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ascii-font-family: sans-serif; mso-hansi-font-family: sans-serif; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">。分支线如果没有接终端，会有反射信号，对通讯产生较强的干扰，应将其去掉。</span><span lang="EN-US" style="FONT-SIZE: 13.5pt; FONT-FAMILY: sans-serif; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><br/><br/><shapetype id="_x0000_t75" stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" opreferrelative="t" ospt="75" coordsize="21600,21600"><stroke joinstyle="miter"></stroke><formulas><f eqn="if lineDrawn pixelLineWidth 0"></f><f eqn="sum @0 1 0"></f><f eqn="sum 0 0 @1"></f><f eqn="prod @2 1 2"></f><f eqn="prod @3 21600 pixelWidth"></f><f eqn="prod @3 21600 pixelHeight"></f><f eqn="sum @0 0 1"></f><f eqn="prod @6 1 2"></f><f eqn="prod @7 21600 pixelWidth"></f><f eqn="sum @8 21600 0"></f><f eqn="prod @7 21600 pixelHeight"></f><f eqn="sum @10 21600 0"></f></formulas><path oconnecttype="rect" gradientshapeok="t" oextrusionok="f"></path><lock aspectratio="t" vext="edit"></lock></shapetype><shape id="_x0000_i1025" alt="" type="#_x0000_t75" style="WIDTH: 333pt; HEIGHT: 169.5pt;"><imagedata ohref="http://www.xwme.net/blog/attachments/month_0611/42006111894225.gif" src="file:///C:\DOCUME~1\znyqq\LOCALS~1\Temp\msohtml1\01\clip_image001.gif"></imagedata></shape></span></p><p><span lang="EN-US" style="FONT-SIZE: 13.5pt; FONT-FAMILY: sans-serif; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">所以要采用手拉手的连接方式<br style="mso-special-character: line-break;"/><br style="mso-special-character: line-break;"/></span></p>

学习，谢谢

学习，学习再学习！

<p>顶了</p>