改造4-20mA两线制无源数显表第十二贴（作品提交）
<p style="text-align: center;"> </p><p style="text-align: center;"><strong><span style="font-size:24px;">给4-20mA两线制无源数显表增加蓝牙遥控设置电路</span></strong></p>
<p align="center" style="text-align:center"> </p>
<p align="right" style="text-align:right"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">作者：7905</span></span></b></span></span></p>
<p style="text-align:justify"><strong><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">一、作品简介</span></span></span></span></strong></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"> <span style="font-size:14.0pt"><span style="font-family:宋体">先给出作品最终工作效果照片：</span></span></span></span></p>
<p style="text-align:justify"> </p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">照片中左上角为本项目作品：</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">模块插接在自制的光耦隔离电路板上，其整体再与被改造目标仪表（</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">两线制无源数显表）相串联后接入被测信号源也是供电电源的</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">电流环路中，在实际工作时的零点电流</span></span><span lang="EN-US" style="font-size:14.0pt">4mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">供电时，目标仪表在电流模式下显示</span></span><span lang="EN-US" style="font-size:14.0pt">4.000mA;</span><span style="font-size:14.0pt"><span style="font-family:宋体">作品电路板整体压降</span></span><span lang="EN-US" style="font-size:14.0pt">2.513V</span><span style="font-size:14.0pt"><span style="font-family:宋体">；通过手机</span></span><span lang="EN-US" style="font-size:14.0pt">APP</span><span style="font-size:14.0pt"><span style="font-family:宋体">向作品电路上的</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">发送改动量程或者单位设置命令，目标仪表（当前自身电压降</span></span><span lang="EN-US" style="font-size:14.0pt">1V</span><span style="font-size:14.0pt"><span style="font-family:宋体">多点）就会被蓝牙遥控改变设置状态，比如切换不同量程或不同被测物理量单位显示等。</span></span></span></span></p>
<p> </p>
<p style="text-align:justify"><strong><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">二、系统框图</span></span></span></span></strong></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">项目总体应用情况示意图：</span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">在实际的工业现场应用中，各种各样的</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">两线制传感器变送器把被测物理量归一化转变成</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">电流，再通过采样电阻把对应的电压信号送进工控机或者</span></span><span lang="EN-US" style="font-size:14.0pt">PLC</span><span style="font-size:14.0pt"><span style="font-family:宋体">等进行后续控制处理；为了便于人机交互，市场上出现了大量能够实时现场显示被测环路电流或者电流所对应物理量值的数显仪表</span></span><span style="font-size:14.0pt"><span style="font-family:宋体">－</span></span><span style="font-size:14.0pt"><span style="font-family:宋体">－</span></span><span style="font-size:14.0pt"><span style="font-family:宋体">也就是本项目要改造的目标仪表：</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">两线制无源数显表，这类仪表多数可以通过本身自带的按键操作进行一些设置改动，我要改造的这台仪表则是需要与电脑连接后通过专用的</span></span><span lang="EN-US" style="font-size:14.0pt">PC</span><span style="font-size:14.0pt"><span style="font-family:宋体">机软件进行改动设置操作才行，借助本次</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">应用大赛活动，我想把它改造成具有可以通过手机蓝牙</span></span><span lang="EN-US" style="font-size:14.0pt">APP</span><span style="font-size:14.0pt"><span style="font-family:宋体">进行现场在线改动设置的功能。</span></span></span></span></p>
<p style="text-align:justify"> </p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">目标描述起来简单明了，实现起来也还需要先对整体方案进行评估论证才能确保达成目标，目前来说我遇到的所有蓝牙模块中这个</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">是封装体积最小的（</span></span><span lang="EN-US" style="font-size:14.0pt">SIP51</span><span style="font-size:14.0pt"><span style="font-family:宋体">封装小到</span></span><span lang="EN-US" style="font-size:14.0pt">8*6</span><span style="font-size:14.0pt"><span style="font-family:宋体">毫米），工作电压竟然低到</span></span><span lang="EN-US" style="font-size:14.0pt">1.1V,</span><span style="font-size:14.0pt"><span style="font-family:宋体">规格书载</span></span><span lang="EN-US" style="font-size:14.0pt">3V</span><span style="font-size:14.0pt"><span style="font-family:宋体">时</span></span><span lang="EN-US" style="font-size:14.0pt">RX</span><span style="font-size:14.0pt"><span style="font-family:宋体">峰值电流</span></span><span lang="EN-US" style="font-size:14.0pt">3</span><span style="font-size:14.0pt"><span style="font-family:宋体">毫安，针对本项目应用无疑是业界不二人选。按最直白的电路设计思维就是把</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">电路接到原仪表电路上，蓝牙发过命令来直接转成</span></span><span lang="EN-US" style="font-size:14.0pt">IO</span><span style="font-size:14.0pt"><span style="font-family:宋体">口线去控制原仪表的编程口进行设置就行了，如下图方案一所示：</span></span></span></span></p>
<p style="text-align:justify"> </p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">在收到开发板熟悉一阵后做了</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">蓝牙在线侦听待机的耗电电流实验：上电没连接</span></span><span lang="EN-US" style="font-size:14.0pt">APP</span><span style="font-size:14.0pt"><span style="font-family:宋体">时待机耗电约</span></span><span lang="EN-US" style="font-size:14.0pt">1.1mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">左右，实测过目标仪表最低工作驱动电流</span></span><span lang="EN-US" style="font-size:14.0pt">2.8</span><span style="font-size:14.0pt"><span style="font-family:宋体">毫安（还能有显示），理论上好像搭个边儿，可是实际接到一起合成一体后，直接给上</span></span><span lang="EN-US" style="font-size:14.0pt">4</span><span style="font-size:14.0pt"><span style="font-family:宋体">毫安，仪表怎么也亮不起来了，判断单片机在启动一刻的瞬时电流都会远超常态值的特性，这种有俩单片机加一起三个核（</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">含双核）的电路能在</span></span><span lang="EN-US" style="font-size:14.0pt">4</span><span style="font-size:14.0pt"><span style="font-family:宋体">毫安下起得来估计也算怪事了。此路不通。接下来的思路是模仿目标仪表对环路总线取电升压构成自身电路电源（相对于目标仪表，改造电路后置），或者生成负压电源（相对于目标仪表，改造电路前置），目的就是要把两套电路电源轨“扯平”以满足可通讯需求，方案图如下：</span></span></span></span></p>
<p style="text-align:justify"> </p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">细想起来却有个隐藏的风险：靠被测电流取电工作的特点决定了随着电流变动其取电输出压降也是波动的，实测目标仪表在低工作电流时本身压降</span></span><span lang="EN-US" style="font-size:14.0pt">1V</span><span style="font-size:14.0pt"><span style="font-family:宋体">左右（其内部电路升高成了</span></span><span lang="EN-US" style="font-size:14.0pt">2.8V+</span><span style="font-size:14.0pt"><span style="font-family:宋体">），自制一套电源系统的话，无论在原仪表前置电路降压，或是后置电路升压都无法实现两个独立电源总是做到统一参考电平点，会导致通信双方</span></span><span lang="EN-US" style="font-size:14.0pt">IO</span><span style="font-size:14.0pt"><span style="font-family:宋体">口线电平参考不对齐，造成陡增电流风险，此路也不通。问题的关键点在于两套电路必须要通信，通信口线两端电平参考不能保持稳定，就只能寻找不需要依靠参考电平统一的通信方式，于是想到方案三，如图：</span></span></span></span></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">这也是本项目的最终选择方案，可以看出改造电路无论前置还是后置，都不用担心与目标仪表间波动的地压差了，这就是选出靠光耦来通信的办法以规避电流短路的过程；热衷于秉承“如无必要，勿增实体”的简单有效原则，决定采用光耦通信后，加改部分电路电源就既不用升压，也不用降压，只用简单的硅二极管串联产生的正向压降做工作电源，连</span></span><span lang="EN-US" style="font-size:14.0pt">LDO</span><span style="font-size:14.0pt"><span style="font-family:宋体">都省掉，只要能实现让</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">在有限电流下能驱动光耦就行，这样的方案定出来简直显得简单到像没经过什么设计一样，“低陋”的外围也能实现“高上”的电路功能，显然是依靠凭借了</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">集成的优异性能。硬件实现示意框图：</span></span></span></span></p>
<p></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">软件分两部分：手机端和</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">端。</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">的程序直接采用官方例程中的</span></span><span lang="EN-US" style="font-size:14.0pt">peripheral_server_uart</span><span style="font-size:14.0pt"><span style="font-family:宋体">，只是把蓝牙名称改成了</span></span></span></span></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">“</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10_Jul05_7905</span><span style="font-size:14.0pt"><span style="font-family:宋体">”，串口波特率改成</span></span><span lang="EN-US" style="font-size:14.0pt">2400</span><span style="font-size:14.0pt"><span style="font-family:宋体">，其它不变，所以也不用画框图了；手机端软件采用面向对象编程的中文</span></span><span lang="EN-US" style="font-size:14.0pt">E4A</span><span style="font-size:14.0pt"><span style="font-family:宋体">编制，框图如下：</span></span></span></span></p>
<p style="text-align:justify"> </p>
<p style="margin-left:8px; text-align:justify"><strong><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">三、各部分功能说明</span></span></span></span></strong></p>
<p style="margin-left:28px; text-indent:15.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">仪表配套上位机配置软件界面如下：</span></span></span></span></p>
<p style="margin-left:28px; text-indent:15.0pt; text-align:justify"></p>
<p><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">从界面直观可见软件首先具有设置量程大小和物理单位的功能区，其它串口设置和仪表校准、复位等之类就先不管了（工厂出厂前标定或校准仪表用的），本项目只求做到通过蓝牙遥控可以改动仪表的量程大小以及物理单位设置就达到目的了。软件左上功能区下拉列表点开后显示如下：</span></span></span></span></p>
<p style="margin-left:28px; text-indent:15.0pt; text-align:justify"> <span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">默认是显示电流的，所以起、止值也就自动填的</span></span><span lang="EN-US" style="font-size:14.0pt">4</span><span style="font-size:14.0pt"><span style="font-family:宋体">和</span></span><span lang="EN-US" style="font-size:14.0pt">20</span><span style="font-size:14.0pt"><span style="font-family:宋体">，这种状态仪表就是个</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">的电流表；如果选择了其它单位，比如</span></span><span lang="EN-US" style="font-size:14.0pt">KPa</span><span style="font-size:14.0pt"><span style="font-family:宋体">等，仪表的零点和满度值就可以自行设置了，填写好后点击下方的“下载设置”按钮，新的状态就写进并保存在仪表了，比如</span></span><span lang="EN-US" style="font-size:14.0pt">0-100KPa</span><span style="font-size:14.0pt"><span style="font-family:宋体">等等。</span></span></span></span></p>
<p style="margin-left:28px; text-indent:15.0pt; text-align:justify"> </p>
<p style="margin-left:28px; text-indent:15.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">对于原配套</span></span><span lang="EN-US" style="font-size:14.0pt">PC</span><span style="font-size:14.0pt"><span style="font-family:宋体">机设置软件下发数据中具体数组元素与量程值或单位等的对应关系，通过以下制表观察办法获得：</span></span></span></span></p>
<p style="margin-left:28px; text-align:justify"></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">可见对应代表单位的数组元素是第四字节；第七、八字节为量程，第七字节是高八位。数据获取就是开两个串口软件，一个是原配置软件发数据，另一个软件接收，这样可以把任何关心的信息通过发数软件的不同“特殊点”配置结果通过“下载设置”发送并“截获”出来。光耦隔离传输两种电源下高低电平信号是通过如下所示原理图实现的：</span></span></span></span></p>
<p style="text-align:justify"> </p>
<p style="margin-left:28px; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">图中“</span></span><span lang="EN-US" style="font-size:14.0pt">2V-IO-2</span><span style="font-size:14.0pt"><span style="font-family:宋体">”代表</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">的发送端口，“</span></span><span lang="EN-US" style="font-size:14.0pt">3.3V-IO-2</span><span style="font-size:14.0pt"><span style="font-family:宋体">”代表目标仪表端单片机接收端口。</span></span></span></span></p>
<p style="margin-left:28px; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">手机</span></span><span lang="EN-US" style="font-size:14.0pt">APP</span><span style="font-size:14.0pt"><span style="font-family:宋体">界面比较简单，望文知义型的，不必多说，界面如下：</span></span></span></span></p>
<p style="margin-left:28px; text-align:justify"></p>
<p style="margin-left:8px; text-align:justify"><strong><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">四、作品源码</span></span></span></span></strong></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">因为</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">代码直接采用官方例程，只做了两处相关名称和波特率改动，就不列出源码了，手机端</span></span><span lang="EN-US" style="font-size:14.0pt">E4A</span><span style="font-size:14.0pt"><span style="font-family:宋体">程序源码按提交建议上传指定地址总是处于“暂未审核”状态，所以打算先随本提交贴单独上传文档吧，请见附件。</span></span></span></span></p>
<p> </p>
<p style="margin-left: 8px; text-align: justify;"><strong><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">五、作品功能演示视频</span></span></span></span></strong></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">最终功能演示视频地址：</span></span></span></span></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span lang="EN-US" style="font-size:14.0pt">1</span><span style="font-size:14.0pt"><span style="font-family:宋体">、</span></span><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://training.eeworld.com.cn/course/6054/learn?preview=1#lesson/30540" style="color:blue; text-decoration:underline">2021<span lang="EN-US" style="font-family:宋体">安森美</span>RSL10<span lang="EN-US" style="font-family:宋体">应用赛</span>-<span lang="EN-US" style="font-family:宋体">数显表改造项目结项视频</span> - RSL10<span lang="EN-US" style="font-family:宋体">蓝牙模块耗电测试</span> - EEWORLD<span lang="EN-US" style="font-family:宋体">大学堂</span></a></span></span></span></span></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span lang="EN-US" style="font-size:14.0pt">2</span><span style="font-size:14.0pt"><span style="font-family:宋体">、</span></span><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://www.bilibili.com/video/BV18B4y1T7Tt/" style="color:blue; text-decoration:underline">2021<span lang="EN-US" style="font-family:宋体">安森美</span>RSL10<span lang="EN-US" style="font-family:宋体">应用赛</span>-<span lang="EN-US" style="font-family:宋体">数显表改造项目结项演示视频</span>_<span lang="EN-US" style="font-family:宋体">哔哩哔哩</span>_bilibili</a></span></span></span></span></p>
<p style="text-align:justify"><iframe allowfullscreen="true" frameborder="0" height="450" src="//player.bilibili.com/player.html?bvid=18B4y1T7Tt&page=1" style="background:#eee;margin-bottom:10px;" width="750"></iframe></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">视频简介：视频里我用了三块辅助仪表，一台键控恒流输出电流源表，一台电流表，一台电压表。电流源表的正极输出先经过串接电流表（用于观察总电路电流），再接到本项目自制的光耦隔离板</span></span><span lang="EN-US" style="font-size:14.0pt">+RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">组合电路，再串接过目标仪表后回到电流源表负极；电压表跨接在自制电路的一进一出电源两端，用于观察实际电路在不同回路电流下工作压降值。目标仪表一般初始都设置成电流测量模式，所以一上电就显示回路电流值，改变电流源输出值，先经过测量中点，即</span></span><span lang="EN-US" style="font-size:14.0pt">12mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">，看一下目标仪表示值，再升到满度值</span></span><span lang="EN-US" style="font-size:14.0pt">20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">，看示值是否准确，之后回到中点，再回到零点</span></span><span lang="EN-US" style="font-size:14.0pt">4mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">；第二轮演示是通过手机</span></span><span lang="EN-US" style="font-size:14.0pt">APP</span><span style="font-size:14.0pt"><span style="font-family:宋体">改动设置目标仪表成</span></span><span lang="EN-US" style="font-size:14.0pt">500KPa</span><span style="font-size:14.0pt"><span style="font-family:宋体">压力测量状态，改设完成看到零点值显示由</span></span><span lang="EN-US" style="font-size:14.0pt">4</span><span style="font-size:14.0pt"><span style="font-family:宋体">（</span></span><span lang="EN-US" style="font-size:14.0pt">mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">）变成</span></span><span lang="EN-US" style="font-size:14.0pt">0</span><span style="font-size:14.0pt"><span style="font-family:宋体">，中点值显示接近</span></span><span lang="EN-US" style="font-size:14.0pt">250</span><span style="font-size:14.0pt"><span style="font-family:宋体">，满度值接近</span></span><span lang="EN-US" style="font-size:14.0pt">500</span><span style="font-size:14.0pt"><span style="font-family:宋体">，回到中点、回到零点后，第三轮演示把量程改成</span></span><span lang="EN-US" style="font-size:14.0pt">100</span><span style="font-size:14.0pt"><span style="font-family:宋体">，单位改成摄氏度，写入仪表后再验证零、中、满度电流下显示的</span></span><span lang="EN-US" style="font-size:14.0pt">0</span><span style="font-size:14.0pt"><span style="font-family:宋体">、</span></span><span lang="EN-US" style="font-size:14.0pt">50</span><span style="font-size:14.0pt"><span style="font-family:宋体">、</span></span><span lang="EN-US" style="font-size:14.0pt">100</span><span style="font-size:14.0pt"><span style="font-family:宋体">（误差</span></span><span lang="EN-US" style="font-size:14.0pt">0.3</span><span style="font-size:14.0pt"><span style="font-family:宋体">％以内</span></span><span style="font-size:14.0pt"><span style="font-family:宋体">）摄氏度；最后一轮演示是直接点选</span></span><span lang="EN-US" style="font-size:14.0pt">APP</span><span style="font-size:14.0pt"><span style="font-family:宋体">下拉列表里的</span></span><span lang="EN-US" style="font-size:14.0pt">mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">选项，可见量程值自动回填成</span></span><span lang="EN-US" style="font-size:14.0pt">20</span><span style="font-size:14.0pt"><span style="font-family:宋体">，写入仪表成功后，仪表就又恢复到测量显示电流表状态。</span></span></span></span></p>
<p> </p>
<p style="margin-left:8px; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">六、项目总结</span></span></b></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"> </p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">从项目之初直到进行到前大半段的时间里，我都一直以为项目的重点在加改电路的电源处理和通信方式的选择上，这两条验证通过了项目就相当于完成了。前提必要条件都具备：原配电脑上位机设置软件有；目标仪表正常可用；</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">模块硬件现成的，例程现成的，开发工具齐备；</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">本身功耗大前提也满足：“</span></span><span lang="EN-US" style="font-size:14.0pt">Supply Voltage Range: 1.1 − 3.3 V</span><span style="font-size:14.0pt"><span style="font-family:宋体">；</span></span><span lang="EN-US" style="font-size:14.0pt">Peak Rx Current = 3.0 mA (3 V VBAT)</span><span style="font-size:14.0pt"><span style="font-family:宋体">”，总体预测应该可以实现目标。其实在</span></span><span lang="EN-US" style="font-size:14.0pt">PCB</span><span style="font-size:14.0pt"><span style="font-family:宋体">投板之前我已经用相关元件搭棚焊做过一次模拟电路测试：就是用</span></span><span lang="EN-US" style="font-size:14.0pt">5</span><span style="font-size:14.0pt"><span style="font-family:宋体">只硅二极管串联做压降取电给</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">模块供电，用光耦做隔离往电脑发数据，没有问题。板子做回迫不及待地按照从仪表原配</span></span><span lang="EN-US" style="font-size:14.0pt">PC</span><span style="font-size:14.0pt"><span style="font-family:宋体">端软件串口截获的数据让</span></span><span lang="EN-US" style="font-size:14.0pt">RSL10</span><span style="font-size:14.0pt"><span style="font-family:宋体">通过自制光耦隔离板往仪表发数据就怎么也没有反应，项目进程被一步步打回原形：怀疑过光耦问题、怀疑过总线取电供电不稳问题、怀疑过隔离后数据波形有畸变等等都通过想各种办法一一应对，总是不行，想起华罗庚说过的一句话，“善于退，足够的退，退到最原始而又不失去重要性的地方”</span></span><span lang="EN-US" style="font-size:14.0pt">——</span><span style="font-size:14.0pt"><span style="font-family:宋体">重新步步为营做实验吧，于是有了后来的做基础实验的发帖，隔离传数据电平的，隔离传数据字节的，甚至做让模拟用的</span></span><span lang="EN-US" style="font-size:14.0pt">MEGA88</span><span style="font-size:14.0pt"><span style="font-family:宋体">单片机收隔离发来的“原装”截获数据判断是否有误，都没问题！陷入了对传输协议的不知是软件还是硬件问题的困惑，过程中还伴随一些从来没遇见的“诡异”现象：电脑模拟串口还失灵了，有时候不收数，有时候明明设置波特率却不起作用，设置成任何接收波特率后发来的数都能一样正确接收显示，至今都没搞明白哪出了问题；后来干脆换一台电脑做实验才避开这个大坑！换电脑后串口“可信”了，又做了这样一个实验：让电脑用原配上位机软件发数据改动仪表设置，正常，改用其它串口软件发送相同截获的数据竟然不行，没反应！波特率一样啊，同时开两个串口上位机软件，一个接收数据，另一个交换测试由原配上位机和另外软件发相同数据，结果看到接收到的数据的确是一样一样的！不用自制电路，从电脑用别的软件发合法数据都不行，陷入僵局。苦闷中甚至生起对原仪表设计者反盗版技术运用效果的敬意！这样具体又不像问题的问题真实存在。日思夜想不得其解。“无魔不成道”，呆呆无意识的让电脑发数、接数，看屏幕上欻欻更新的一帧帧数据，也不知哪一次受了灵光的点拨：发现从原配软件发数时接收过来的数据帧好像有些微的不一样</span></span><span lang="EN-US" style="font-size:14.0pt">——</span><span style="font-size:14.0pt"><span style="font-family:宋体">似乎有慢那么一丢丢，用示波器查看，还真是：原配软件发的数据字节和字节间有一点点延时！真相大白！真是得来全不费功夫！突破性的要点就是：让手机</span></span><span lang="EN-US" style="font-size:14.0pt">APP</span><span style="font-size:14.0pt"><span style="font-family:宋体">发数时每个字节间都加上</span></span><span lang="EN-US" style="font-size:14.0pt">100</span><span style="font-size:14.0pt"><span style="font-family:宋体">毫秒延时。</span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"> </p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">两线制无源数显表，所以叫“无源”，是指其工作在测量状态时不需要外接电源供电，仅仅依靠被测量电路回路的</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">信号的电能就能维持自身电路的正常工作；所以叫“两线制”，是指作为一种测量仪表，其对外接口只有两根引出线，工作时仅凭这两根引线串联接入被测回路就可以测量、显示所串接入的电路里流经电流的大小；</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">是到目前为止业界还在广泛采用的工业现场（也包括民用）应用总线的信号规范</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="font-family:"微软雅黑",sans-serif"><span style="color:#343434">——</span></span></span><span style="font-size:14.0pt"><span style="font-family:宋体">即以直流</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">大小范围的电流代表被测量的各种物理量的大小，比如压力、温度、液位、流量、物位距离等等，打个比方要监测</span></span><span lang="EN-US" style="font-size:14.0pt">0-100</span><span style="font-size:14.0pt"><span style="font-family:宋体">℃的温度变化，我们就可以以4毫安代表对应低点（零点）的0℃，以20毫安代表对应高点（满量程）的100℃，这样电流值与温度值就建立起一一对应的比例关系了，我们就能根据电信号</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="font-family:"微软雅黑",sans-serif"><span style="color:#343434">——</span></span></span><span style="font-size:14.0pt"><span style="font-family:宋体">电流值的大小求得对应温度值的大小，其它物理量如压力、物位、流量、液位等等也同理，因为这种</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">电流环总线方式应用广泛，所以市场上就应运而生了一种专门测量并显示这种电流环信号的仪表，因为是数字化的电子仪表，所以除了可以直接测量显示电流大小外，还能通过改变设置实现附带量程转换、单位转换或者量程百分比显示的功能，比如原来要测量显示</span></span><span lang="EN-US" style="font-size:14.0pt">0</span><span style="font-size:14.0pt"><span style="font-family:宋体">到</span></span><span lang="EN-US" style="font-size:14.0pt">100KPa</span><span style="font-size:14.0pt"><span style="font-family:宋体">量程的压力，想改成要测量显示</span></span><span lang="EN-US" style="font-size:14.0pt">0</span><span style="font-size:14.0pt"><span style="font-family:宋体">到</span></span><span lang="EN-US" style="font-size:14.0pt">1000KPa</span><span style="font-size:14.0pt"><span style="font-family:宋体">量程的压力范围，由原理可知其对应的被测信号没变，还是</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">电流大小，只不过每单位电流对应的物理量值更改了而已，仪表内部根据设置自动进行计算、转换就能实现直接显示被测物理量大小的目的了，推广一下，还用同一台仪表去改测</span></span><span lang="EN-US" style="font-size:14.0pt">0</span><span style="font-size:14.0pt"><span style="font-family:宋体">到</span></span><span lang="EN-US" style="font-size:14.0pt">5</span><span style="font-size:14.0pt"><span style="font-family:宋体">米深的水位高低，同理也是直接可以替换的，唯一要改动的就是对仪表内先置的量程大小或物理单位做一下改动设置而已，由此可见这种仪表的适用性较广，另外不需要额外电源供电也是优势特色。我手头这种</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">测量表就是如上所述功能的数显仪表，不过要对其改动量程或者物理单位设置的话需要把仪表拿到生产标定工位上，连接电脑通过专用软件才能改设参数，对于千差万别的各种使用工况来说，比如有的仪表是安装在工矿企业的高大管路上，有的是安装在工厂机房的窄小角落里，粉尘、油污的环境都有可能，很多是不利于工作人员近身去拆卸和安装的环境，况且拆下来拿到办公室甚至拿回生产厂家去改设参数还会造成现场电路断线停测，而实际参数改设过程却只是个简短过程，只是连上电脑写进仪表一串参数而已，分分钟搞定的事，却花费相对很多的人力和时间用在拆卸和安装过程上，实属无用功，况且某些工况还不允许断电停工以支持拆卸在线工作的仪表，为此，正好借助这次比赛提供的资源进行一次仪表改造试验，力求把无用功的拆、装仪表过程省掉，也不用现场爬高、钻低的费时费力耗人工去改设参数，只需要工作人员走到仪表附近凭借智能手机蓝牙遥控操作就完成同样任务，实现现场参数设置轻松在线改动，应用便利、前景广阔。挑战也是有的，前面提到，这种仪表是自身不带电源的，况且要想正常工作，整机工作耗电要低于</span></span><span lang="EN-US" style="font-size:14.0pt">4</span><span style="font-size:14.0pt"><span style="font-family:宋体">毫安，因为被测信号电流也就是电能来源最小要低到</span></span><span lang="EN-US" style="font-size:14.0pt">4mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">，仪表本身电路包括微处理器、变换电路、显示电路要正常工作就都需要耗电，甚至几个微安的电流都是宝贵的，原有仪表电路设计估计都已经“榨干了”</span></span><span lang="EN-US" style="font-size:14.0pt">4mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">以下的每一点富余能量，想增加无线通讯功能进去挑战不小，最终通过采用光耦隔离通信方案得以成功解决，如愿以偿的把这款无源</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">数显表改造成了具有可蓝牙遥控设置的功能。</span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><strong><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">帖子分享链接汇总：</span></span></span></span></strong></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1162942-1-1.html" style="color:blue; text-decoration:underline">2021<span lang="EN-US" style="font-family:宋体">安森美安富利</span>RSL10<span lang="EN-US" style="font-family:宋体">蓝牙</span>SoC<span lang="EN-US" style="font-family:宋体">开发设计赛第一帖</span></a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1162966-1-1.html" style="color:blue; text-decoration:underline">2021<span lang="EN-US" style="font-family:宋体">安森美安富利</span>RSL10<span lang="EN-US" style="font-family:宋体">蓝牙</span>SoC<span lang="EN-US" style="font-family:宋体">开发设计赛第二帖</span>(<span lang="EN-US" style="font-family:宋体">初改例程</span>) </a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1164010-1-1.html" style="color:blue; text-decoration:underline">2021<span lang="EN-US" style="font-family:宋体">安森美安富利</span>RSL10<span lang="EN-US" style="font-family:宋体">蓝牙</span>SoC<span lang="EN-US" style="font-family:宋体">开发设计赛第三帖</span>(<span lang="EN-US" style="font-family:宋体">再改例程</span>)--<span lang="EN-US" style="font-family:宋体">没图再发一遍试试</span> </a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1165650-1-1.html" style="color:blue; text-decoration:underline">2021<span lang="EN-US" style="font-family:宋体">安森美安富利</span>RSL10<span lang="EN-US" style="font-family:宋体">蓝牙</span>SoC<span lang="EN-US" style="font-family:宋体">开发设计赛第四帖（蓝牙电流）</span></a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1169076-1-1.html" style="color:blue; text-decoration:underline">2021<span lang="EN-US" style="font-family:宋体">安森美安富利</span>RSL10<span lang="EN-US" style="font-family:宋体">蓝牙</span>SoC<span lang="EN-US" style="font-family:宋体">开发设计赛第五帖（打样投板）</span></a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1169218-1-1.html" style="color:blue; text-decoration:underline"><span lang="EN-US" style="font-family:宋体">改造</span>4-20mA<span lang="EN-US" style="font-family:宋体">两线制无源数显表第六贴（总示意图）</span></a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1169489-1-1.html" style="color:blue; text-decoration:underline"><span lang="EN-US" style="font-family:宋体">改造</span>4-20mA<span lang="EN-US" style="font-family:宋体">两线制无源数显表第七贴（软件简介）</span></a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1170341-1-1.html" style="color:blue; text-decoration:underline"><span lang="EN-US" style="font-family:宋体">改造</span>4-20mA<span lang="EN-US" style="font-family:宋体">两线制无源数显表第七贴（光耦实验）</span></a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1171172-1-1.html" style="color:blue; text-decoration:underline"><span lang="EN-US" style="font-family:宋体">改造</span>4-20mA<span lang="EN-US" style="font-family:宋体">两线制无源数显表第八贴（硬件照片）</span></a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1171474-1-1.html" style="color:blue; text-decoration:underline"><span lang="EN-US" style="font-family:宋体">改造</span>4-20mA<span lang="EN-US" style="font-family:宋体">两线制无源数显表第十贴（小功告成）</span> </a></span></span></span></span></p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span class="MsoHyperlink" style="color:blue"><span style="text-decoration:underline"><a href="https://bbs.eeworld.com.cn/thread-1171601-1-1.html" style="color:blue; text-decoration:underline"><span lang="EN-US" style="font-family:宋体">改造</span>4-20mA<span lang="EN-US" style="font-family:宋体">两线制无源数显表第十一贴（过程小结）</span></a></span></span></span></span></p>
<p>
<p style="margin-left:8px; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:16.0pt"><span style="font-family:"微软雅黑",sans-serif">七、其他</span></span></b></span></span></p>
</p>
<p style="text-indent:21.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="font-family:宋体">对于业内同行来讲，显然可见这次成功改造的延申意义，即普通常见的两线制仪表可以通过这种办法简单可靠的升级成具有蓝牙通讯功能的仪表，且被升级仪表不用做任何电路结构变更都行，当然也可按此思路重新设计靠光耦“分隔”、又一体化的新型两线制</span></span><span lang="EN-US" style="font-size:14.0pt">4-20mA</span><span style="font-size:14.0pt"><span style="font-family:宋体">蓝牙仪表，拥有可以媲美像</span></span><span lang="EN-US" style="font-size:14.0pt">HART</span><span style="font-size:14.0pt"><span style="font-family:宋体">通信类智能仪表的可双向通讯功能，却不必受限于依靠实际物理布线束缚，不必操心办理加入</span></span><span lang="EN-US" style="font-size:14.0pt">HART</span><span style="font-size:14.0pt"><span style="font-family:宋体">通信基金会会员的相关事宜，应用中不用额外再购买价格不菲的</span></span><span lang="EN-US" style="font-size:14.0pt">HART</span><span style="font-size:14.0pt"><span style="font-family:宋体">通信手操器，只需一部人手皆有、不太古董的智能手机就行了。</span></span><span lang="EN-US" style="font-size:14.0pt">2021-7-12</span></span></span></p>
<p> </p>
<p>楼主介绍方案三改造很实用，充分利用RSL10封装体积小的特点，比较适合4-20mA两线制无源数显表，通过手机蓝牙控制测量</p>
<p> </p>
<p>想法非常不错！点个赞！</p>
Jacktang 发表于 2021-7-12 11:22
楼主介绍方案三改造很实用，充分利用RSL10封装体积小的特点，比较适合4-20mA两线制无源数显表，通过手机蓝 ...
<p><img height="48" src="https://bbs.eeworld.com.cn/static/editor/plugins/hkemoji/sticker/facebook/handshake.gif" width="48" /></p>
w494143467 发表于 2021-7-12 16:45
想法非常不错！点个赞！
<p><img height="48" src="https://bbs.eeworld.com.cn/static/editor/plugins/hkemoji/sticker/facebook/handshake.gif" width="48" /></p>
<p>非常详细，非常细心，赞一个。</p>
<p>学习了</p>
<p>楼主好强，支持一下</p>
对于工作电压稳定的场合，我会用电容隔离直流，直接传输信号 soso 发表于 2021-7-13 09:07
非常详细，非常细心，赞一个。
<p><img height="48" src="https://bbs.eeworld.com.cn/static/editor/plugins/hkemoji/sticker/facebook/handshake.gif" width="48" /></p>
dql2016 发表于 2021-7-14 11:26
学习了
<p>您谦虚了，抽时间学习下您讲的微信小程序双向通信；微信+蓝牙，通讯空间一下就扩展成全球范围了</p>
柠檬酸钠 发表于 2021-7-14 11:34
楼主好强，支持一下
<p>谢谢！</p>
mcu5i51 发表于 2021-7-14 15:45
对于工作电压稳定的场合，我会用电容隔离直流，直接传输信号
<p>“电容隔离直流”看样子是成功经验；算是微分信号传递的吗？是否跨双电源？</p>
<p>太強了，很有用的知識。</p>
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