串口屏收nodered发送的数据，求助？

Waer

taida 发表于 2023-7-31 10:59
终于搞定了，谢谢Waer和cjnt007，用Buffer 做的，先将字符转成Buffer，然后将文本（FFFFFF），也转成Buffer ...

哈哈哈 在上班 所以来迟了
其实把你上一个节点输出payload的时候格式改成文本就可以

[{"id":"bc7f85cc82713bed","type":"tab","label":"流程 2","disabled":false,"info":"","env":[]},{"id":"43b82491eb19fc5a","type":"inject","z":"bc7f85cc82713bed","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"123456","payloadType":"str","x":470,"y":360,"wires":[["5dedf802bfc1d293"]]},{"id":"8771cd2730dd7fbb","type":"debug","z":"bc7f85cc82713bed","name":"debug 5","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":840,"y":360,"wires":[]},{"id":"5dedf802bfc1d293","type":"function","z":"bc7f85cc82713bed","name":"","func":"var q = Buffer.from((msg.payload),'hex')\nvar a = Buffer.from('ffffffff', 'hex')\nvar c = Buffer.concat([q,a])\nmsg.payload = c\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":650,"y":360,"wires":[["8771cd2730dd7fbb"]]}]

复制代码

taida

再次感谢！

taida

Waer 发表于 2023-7-31 11:12
哈哈哈 在上班 所以来迟了
其实把你上一个节点输出payload的时候格式改成文本就可以

不好意思，在问一个问题，怎么将字符串相加呢？但是要得到这样的一个格式：
如：

需要的结果 b0.txt = "29.8"

msg.payload 的值是29.8，如果用var a = "b0.txt="+msg.payload，得出的结果是“bo.txt=29.8”，而不是
b0.txt = "29.8"，用String(msg.payload)也是一样的，也就是payload的值上要加“”谢谢！帮忙看看可以怎么实现

Waer

taida 发表于 2023-8-3 18:07
不好意思，在问一个问题，怎么将字符串相加呢？但是要得到这样的一个格式：
如：

你是希望

最初是msg.payload=29.8  

最后是msg.payload=b0.txt="29.8"

这样吗

Waer

taida 发表于 2023-8-3 18:07
不好意思，在问一个问题，怎么将字符串相加呢？但是要得到这样的一个格式：
如：

我还是不确定你具体的使用场景  你说的输出结果是“bo.txt=29.8”
前后的双引号应该只是代表这个内容属于字符串格式  在接收方读取就是bo.txt=29.8
所以不要太纠结这部分
至少我目前学的就到这部分


如果你是为了接收方收到的信号是bo.txt="29.8”
那你可以提前给输入的msg.payload值加上双引号

[{"id":"a56d2dc6bd46c271","type":"inject","z":"bc7f85cc82713bed","name":"已增加双引号的字符串","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"“29.8”","payloadType":"str","x":240,"y":480,"wires":[["88575553e714e43a"]]},{"id":"53be71bd312291bf","type":"debug","z":"bc7f85cc82713bed","name":"debug 8","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":720,"y":480,"wires":[]},{"id":"88575553e714e43a","type":"function","z":"bc7f85cc82713bed","name":"两段字符串拼合输出","func":"var a = "b0.txt=" + msg.payload;\nmsg.payload = a\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":480,"y":480,"wires":[["53be71bd312291bf"]]}]

复制代码

taida

我找了一张淘晶驰的显示屏，现在需要在文本框填入温度，t0是文本框名称，他要求的格式就是t0.text=“文本”，所以必须这个格式，谢谢

taida

写好了，谢谢各位