[分享]485总线结构的门禁系统布线规范及调试方法...

<p class="MsoNormal" style="MARGIN: 0cm="0cm"  0cm="0cm"  0pt"><font size="3"><strong><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">第一章</span> </strong><strong><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">澄清几个概念</span><span lang="EN-US">:</span></strong></font><span lang="EN-US"><br/></span><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">概念一</span><span lang="EN-US">: <a title="" href="http://www.rdgcw.com/" target="_blank">485</a></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">总线的通讯距离可以达到</span><?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:chmetcnv unitname="米" sourcevalue="1200" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"><span lang="EN-US">1200</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">米</span></st1:chmetcnv></font><font size="3"><span lang="EN-US">.<br/></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">其实只是</span><span lang="EN-US">485</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">总线结构理论上</span> <span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">在理想环境的前提下才有可能使得传输距离达到</span><st1:chmetcnv unitname="米" sourcevalue="1200" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"><span lang="EN-US">1200</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">米</span></st1:chmetcnv><span lang="EN-US">.</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">一般是指通讯线材优质达标</span><span lang="EN-US">,波特率</span><span lang="EN-US">9600,</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">只有一台</span><span lang="EN-US">485</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">设备才能使得通讯距离达到</span><st1:CHMETCNV unitname="米" sourcevalue="1200" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"><span lang="EN-US">1200</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">米</span></st1:CHMETCNV><span lang="EN-US">,</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">而且能通讯并不代表每次通讯都正常</span><span lang="EN-US">.</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">所以通常</span><span lang="EN-US">485</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">总线实际的稳定的通讯距离远远达不到</span><st1:CHMETCNV unitname="米" sourcevalue="1200" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"><span lang="EN-US">1200</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">米</span></st1:CHMETCNV><span lang="EN-US">. </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">负载</span><span lang="EN-US">485</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">设备多</span><span lang="EN-US">,</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">线材阻抗不合乎标准</span><span lang="EN-US">,</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">线径过细</span><span lang="EN-US">,</p>
<div>转换器品质不良</span><span lang="EN-US">,</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">设备防雷保护</span><span lang="EN-US">,</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New="New"  Roman'; mso-hansi-font-family: 'Times New="New"  Roman'">波特率的加高等等因素都会降低通讯距离</span><span lang="EN-US">. </span></font>
<p></p>
<p><font face="宋体" size="3">概念二<span lang="EN-US">: 485</span>总线可以带<span lang="EN-US">128</span>台设备进行通讯</font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>其实并不是所有<span lang="EN-US">485</span>转换器都能够带<span lang="EN-US">128</span>台设备的<span lang="EN-US">.</span>要根据<span lang="EN-US">485</span>转换器内芯片采用的型号和<span lang="EN-US">485</span>设备芯片采用的型号来判断的<span lang="EN-US">.</span>谁低就谁的<span lang="EN-US">.</span>一般<span lang="EN-US">485</span>芯片负载能力有三个级别<span lang="EN-US"> 32</span>台<span lang="EN-US"> 128</span>台<span lang="EN-US"> 256</span>台<span lang="EN-US">. </span>理论上的标称往往实际上是达不到的<span lang="EN-US">.</span>通讯距离越长<span lang="EN-US">,</span>波特率越高<span lang="EN-US">,</span>线径越细<span lang="EN-US">,</span>线材质量越差<span lang="EN-US">,</span>转换器品质越差<span lang="EN-US">,</span>转换器电能供应不足<span lang="EN-US">(</span>无源转换器<span lang="EN-US">),</span>防雷保护越强这些都会大大降低真实负载数量<span lang="EN-US">.</span></font></font></p>
<p><font face="宋体" size="3">概念三<span lang="EN-US">: 485</span>总线是一种最简单 最稳定 最成熟的工业<a title="" href="http://www.rdgcw.com/" target="_blank">总线结构</a></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>这种概念是错误的<span lang="EN-US">.</span>应该是<span lang="EN-US">: 485</span>总线是一种用于设备联网的经济型的传统的工业总线方式<span lang="EN-US">. </span>通讯质量是需要根据施工经验进行测试和调试的<span lang="EN-US">. 485</span>总线虽然简单<span lang="EN-US">,</span>但必须严格安装施工规范进行布线<span lang="EN-US">.</span></font></font></p>
<p><strong><span style="FONT-FAMILY: 宋体"><font size="3">第二章 严格几个施工规范<span lang="EN-US">:</span></font></span></strong><span lang="EN-US"><br/><font face="宋体" size="3">485+</font></span><font face="宋体" size="3">和<span lang="EN-US">485-</span>条数据线一定要互为双绞</font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>布线一定要布多股屏蔽双绞线<span lang="EN-US">,</span>多股是为了备用<span lang="EN-US">,</span>屏</p>
<div>蔽是为了出现特殊情况时调试<span lang="EN-US">,</span>双绞是因为<span lang="EN-US">485</span>通讯采用差模通讯原理<span lang="EN-US">,</span>双绞的抗干扰性最好<span lang="EN-US">.</span>不采用双绞线<span lang="EN-US">,</span>是极端错误的</font></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/>485</span>总线一定要是手牵手式的总线结构<span lang="EN-US">,</span>坚决杜绝星型连接和分叉连接</font></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>设备供电的交流电及机箱一定要真实接地<span lang="EN-US">,</span>而且接地良好</font></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>有很多地方表面上有三角插座<span lang="EN-US">,</span>其实根本没有接地<span lang="EN-US">,</span>要小心<span lang="EN-US">.</span>接地良好时<span lang="EN-US">,</span>可以确保设备被雷击 浪涌冲击 静电累计时 可以配合设备的防雷设计较好地释放能量<span lang="EN-US">.</span>保护<span lang="EN-US">485</span>总线设备和相关芯片不受伤害</font></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>避免和强电走在一起<span lang="EN-US">,</span>以免强电对其干扰<span lang="EN-US">.</span></font></font>
<p></p>
<p><strong><span style="FONT-FAMILY: 宋体"><font size="3">第三章 几种常见的通讯故障<span lang="EN-US">:</span></font></span></strong><span lang="EN-US"><br/></span><font face="宋体" size="3">通讯不上<span lang="EN-US">,</span>无反应</font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>可以上传数据<span lang="EN-US">,</span>但不可以下载数据</font></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>通讯时<span lang="EN-US">,</span>系统提示受到干扰<span lang="EN-US">.</span>或者不通讯时<span lang="EN-US">,</span>通讯指示灯也不停地闪烁</font></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>有时能通讯上<span lang="EN-US">,</span>有时通讯不上<span lang="EN-US">.</span>有的指令可以通<span lang="EN-US">,</span>有的指令不可以通<span lang="EN-US">.</span></font></font></p>
<p><strong><span style="FONT-FAMILY: 宋体"><font size="3">第四章 推荐几个调试方法<span lang="EN-US">:</span></font></span></strong><span lang="EN-US"><br/></span><font size="3"><font face="宋体">首先要确保设备接线正确<span lang="EN-US">,</span>且严格合乎<a title="" href="http://www.rdgcw.com/" target="_blank">规范</a><span lang="EN-US">.</span></font></font></p>
<p><font size="3"><font face="宋体">共地法<span lang="EN-US">: </span>用<span lang="EN-US">1</span>条线或者屏蔽线将所有<span lang="EN-US">485</span>设备的<span lang="EN-US">GND</span>地连接起来<span lang="EN-US">,</span>这</p>
<div>样可以避免所有设备之间存在影响通讯的电势差<span lang="EN-US">.</span></font></font>
<p></p>
<p><font size="3"><font face="宋体">终端电阻法<span lang="EN-US">: </span>在最后一台<span lang="EN-US">485</span>设备的<span lang="EN-US">485+</span>和<span lang="EN-US">485-</span>上并接<span lang="EN-US"> 120</span>欧姆的终端电阻来改善通讯质量<span lang="EN-US">.</span></font></font></p>
<p><font size="3"><font face="宋体">中间分段断开法<span lang="EN-US">: </span>通过从中间断开来检查是否是 设备负载过多 通讯距离过长 某台设备损害对整个通讯线路的影响等原因<span lang="EN-US">.</span></font></font></p>
<p><font size="3"><font face="宋体">单独拉线法<span lang="EN-US">: </span>单独简易暂时拉一条线到设备<span lang="EN-US">,</span>这样可以用来排除是否是布线引起了通讯故障<span lang="EN-US">.</span></font></font></p>
<p><font size="3"><font face="宋体">更换转换器法<span lang="EN-US">: </span>随身携带几个转换器<span lang="EN-US">,</span>这样可以排除是否是转换器质量问题影响了通讯质量<span lang="EN-US">.</span></font></font></p>
<p><font size="3"><font face="宋体">笔记本调试法<span lang="EN-US">: </span>先保证自己随身携带的电脑笔记本是通讯正常的设备<span lang="EN-US">,</span>替换客户电脑<span lang="EN-US">,</span>来进行通讯<span lang="EN-US">,</span>如果可以<span lang="EN-US">,</span>则表明客户的电脑的串口有可能被损害或者受伤<span lang="EN-US">.</span></font></font></p>
<p><strong><span style="FONT-FAMILY: 宋体"><font size="3">第五章 提出几个建议和忠告<span lang="EN-US">:</span></font></span></strong><span lang="EN-US"><br/></span><font face="宋体" size="3">建议用户使用和购买门禁厂家提供的<span lang="EN-US">485</span>转换器或者厂家指定推荐品牌的<span lang="EN-US">485</span>转换器</font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>门禁厂家会对与其配套的<span lang="EN-US">485</span>转换器做大量的测试工作<span lang="EN-US">,</span>并且会单独要求<span lang="EN-US">485</span>厂家安装其固定的性能参数进行生产和品质检测<span lang="EN-US">,</span>所以和其门禁设备具备较好的兼容性<span lang="EN-US">.</span>千万不要贪图便宜购买杂牌厂家的<span lang="EN-US">485</span>转换器<span lang="EN-US">.</span></font></font></p>
<p><font size="3"><font face="宋体">严格安装<span lang="EN-US">485</span>总线的施工规范进行施工<span lang="EN-US">,</span>杜绝任何侥幸心理<span lang="EN-US">.</span></font></font></p>
<p><font face="宋体" size="3">对线路较长 负载较多的情况采用主动科学的有预留的解决方案</font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>如果通讯距离过长<span lang="EN-US">,</span>建议如果超过<st1:CHMETCNV unitname="米" sourcevalue="500" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"><span lang="EN-US">500</span>米就采用中继器或者<span lang="EN-US">485<a title="" href="http://www.rdgcw.com/" target="_blank">HUB</a></span>来解决问题</font></font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>如果负载数过多<span lang="EN-US">,</span>建议如果一条总线上超过<span lang="EN-US">30</span>台就采用<span lang="EN-US">485HUB</span>来解决问题<span lang="EN-US">.</span></font></font> </p>
<p></p>
<p><font face="宋体" size="3">现场调试带齐调试设备</font><font size="3"><font face="宋体"><span lang="EN-US">.<br/></span>现场调试一定要随身携带几个确保以前可以接长距离和多负载的转换器 一台常用的电脑笔记本 测试通路断路的万用表 几个<span lang="EN-US">120</span>欧姆的终端电阻<span lang="EN-US">。</span></font></font></p></st1:CHMETCNV></div></div></div>

<p>学习了，顶！</p>
<p>&nbsp;</p>

总结的挺好，正好需要

不错，长些知识了！

可是我们公司做的就不规范，有点担心以后会有问题

<p>学习了！</p>

实际上已经讲到这里了为什么不进一步提供你平时用的转换器或者hub呢？这样我们也可以参考一下呀

<p>请问楼主</p>
<p>　　　１２００bps和９６００bps哪个高？</p>

不见回答?

<p><a title="" href="http://www.rdgcw.com/" target="_blank">485</a><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times new=" Roman?? new="New" ?Times mso-hansi-font-family: Roman?; New?>总线的通讯距离可以达到</span><?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:chmetcnv w:st="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="1200" unitname="米"><span lang="EN-US">1200</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times new=" Roman?? new="New" ?Times mso-hansi-font-family: Roman?; New?>米</span></st1:chmetcnv><font size="3"><span lang="EN-US">.<br/></span></font></p>
<p>我用全铜的网络线，拉了1500米，一样可以，不知道有没有人拉更长的？</p>

好东西，每次我们都是直接拉了搞

1200米总线不如用光纤吧

学习了

原来485通讯也有这么多标准学习了

学习了！！

<p>不错很有价值</p>

学习了

顶

顶

<p>总结的很好，学习了</p>