[原创]485网络通讯方式分析（1）

monsoon

<p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">&nbsp;1</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">总线应采用什么样的通讯线？一条总线上可以挂接多少台设备？</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">&nbsp;</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">必须采用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">RVSP</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">屏蔽双绞线。所用屏蔽双绞线规格，与</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通讯线的距离和挂接的设备数量有关，如下表所示。采用屏蔽双绞线有助于减少和消除两根</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通信线之间产生的分布电容以及来自于通讯线周围产生的共模干扰。</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通讯距离</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">设备数量</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通讯线规格</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman"> 1<chmetcnv wst="on" unitname="m" sourcevalue="400" hasspace="False" negative="True" numbertype="1" tcsc="0">-400m</chmetcnv> 1 - 32 </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">台</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <chmetcnv wst="on" unitname="mm" sourcevalue=".5" hasspace="False" negative="False" numbertype="1" tcsc="0">0.5mm</chmetcnv>2 400<chmetcnv wst="on" unitname="m" sourcevalue="800" hasspace="False" negative="True" numbertype="1" tcsc="0">-800m</chmetcnv> 1 - 16 </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">台</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <chmetcnv wst="on" unitname="mm" sourcevalue=".5" hasspace="False" negative="False" numbertype="1" tcsc="0">0.5mm</chmetcnv>2 400<chmetcnv wst="on" unitname="m" sourcevalue="800" hasspace="False" negative="True" numbertype="1" tcsc="0">-800m</chmetcnv> 17 - 32 </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">台</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <chmetcnv wst="on" unitname="mm" sourcevalue=".75" hasspace="False" negative="False" numbertype="1" tcsc="0">0.75mm</chmetcnv>2 800<chmetcnv wst="on" unitname="m" sourcevalue="1200" hasspace="False" negative="True" numbertype="1" tcsc="0">-1200m</chmetcnv> 1 - 8 </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">台</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <chmetcnv wst="on" unitname="mm" sourcevalue=".5" hasspace="False" negative="False" numbertype="1" tcsc="0">0.5mm</chmetcnv>2 800<chmetcnv wst="on" unitname="m" sourcevalue="1200" hasspace="False" negative="True" numbertype="1" tcsc="0">-1200m</chmetcnv> 9 - 21 </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">台</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <chmetcnv wst="on" unitname="mm" sourcevalue=".75" hasspace="False" negative="False" numbertype="1" tcsc="0">0.75mm</chmetcnv>2 800<chmetcnv wst="on" unitname="m" sourcevalue="1200" hasspace="False" negative="True" numbertype="1" tcsc="0">-1200m</chmetcnv> 22 - 32</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">台</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <chmetcnv wst="on" unitname="mm" sourcevalue="1" hasspace="False" negative="False" numbertype="1" tcsc="0">1.0mm</chmetcnv>2 </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">工程商大都习惯采用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">5</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">类网线或超</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">5</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">类网线作为</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通信线，这是错误的。这是因为：（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">1</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">普通网线没有屏蔽层，不能防止共模干扰。（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">2</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）网线只有</span><chmetcnv wst="on" unitname="mm" sourcevalue=".2" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">0.2mm</font></span></chmetcnv><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">平方，线径太细，会导致传输距离降低和可挂接的设备减少。</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">3</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）网络线为单股的铜线，相比多芯线而言容易断裂。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">2</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">为什么要接地</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">收发器在规定的共模电压</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">-7V</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">至</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">+12V</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">之间时，才能正常工作。如果超出此范围会影响通讯，严重的会损坏通讯接口。共模干扰会增大上述共模电压。消除共模干扰的有效手段之一是将</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通讯线的屏蔽层用作地线，将机具、电脑等网络中的设备地连接在一起，并由一点可靠地接入大地。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">3</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">电控锁和控制器</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">/</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">读卡器可以用同一个电源共电吗？</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">&nbsp;</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">不能。在电控锁不动作的情况下，</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">SKPS</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">的纹波电压只有</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">40-50mV</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">；</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">一旦动作，即在电控锁在开门和关门时，纹波电压会上升到</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">100mV-300mV</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">，该纹波会通过地线进入控制器和读卡器，导致通讯芯片和</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">CPU</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">发热，导致通讯不稳，严重的还会烧毁芯片。而且电控锁在断电和上电的瞬间，电控锁里面的线圈，会充放电产生一个高达</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">850mA</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">的脉冲，如果电控锁的两端没有并联二极管的话，该纹波信号也会传入控制器和读卡器。推荐一个控制器和它下面挂接的所有读卡器共用一个</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">SKPS</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">电源；该控制器下面每个电控锁各使用一个单独的</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">SKPS</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">电源。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">&nbsp;4</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通信线应如何走线？</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通信线尽量远离高压电线，不要与电源线并行，更不能捆扎在一起。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">5</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。为什么</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">总线要采用手拉手结构，而不能采用星形结构？</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">星形结构会产生反射信号，从而影响到</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">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: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">5</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">米</span></chmetcnv><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。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 style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">门禁系统中，有两个地方应用到</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">总线。一是计算机到下面挂接的控制器，二是控制器到下面挂接的</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">读卡器。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">&nbsp;6</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">总线上设备到设备之间可以有接点吗？</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">&nbsp;</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">在同一个网络系统中，使用同一种电缆，尽量减少线路中的接点。接点处确保焊接良好，包扎紧密，避免松动和氧化。保证一条单一的、连续的信号通道作为总线。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
                                <p></p></font></span></p>