读/写数据返回null-无法执行任何操作-节点串行端口 [英] Read/Write data returns null - Unable to perform any operations - node serialport

问题描述

我第一次使用Serialport，并尝试使用以下方法与作为高度调节台控制器的UART设备建立读写连接.该应用程序是使用电子的桌面应用程序.

I am working with serialport for the first time and trying to establish a read and write connection with an UART device which is a controller of a height adjustment desk by using the below method. The application is a desktop application using electron.

const SerialPort = require('serialport')
const Readline = require('@serialport/parser-readline')
const parser = new Readline()


const port = new SerialPort("COM4",  { 
                baudRate: 9600
 })

这是我使用的代码，port.read()始终返回空值.

This is the code I have used and port.read() always returns null value.

对于写操作，我使用了如下代码:

For the write operation I have used the code like below:

var buf = new Buffer([ 0XF1, 0XF1, 0X01, 0X00, 0X01, 0X7E]);
    port.write(buf, function(err,n) {
    if (err) {
    return console.log('Error on write: ', err.message)
    }
    console.log(n)
    console.log('message written')
})

缓冲区值是用于向上移动办公桌的缓冲区值，但是没有任何操作发生，并且它不返回错误或在回调中返回未定义的值.

The buffer values are the ones for moving the desk up but no operation takes place and it returns no error or returns undefined value in callback.

有关设备和设置的更多详细信息: 使用RJ45转USB连接器连接到桌子的控制盒.

More details on the device and setup: Using an RJ45 to USB connector to connect with the control box of the table.

The definition of the SCI is as below:
（Baud Rate）：9600
（Data Mode）：8
（Stop Bit）：1
（Parity Type）：None
Path: COM3

手机是指我的系统.

基本写操作缓冲区值:

上移= 0XF1 0XF1 0X01 0X00 0X01 0X7E

Move Up=0XF1 0XF1 0X01 0X00 0X01 0X7E

下移= 0XF1 0XF1 0X02 0X00 0X02 0X7E

Move Down=0XF1 0XF1 0X02 0X00 0X02 0X7E

停止动作= 0XF1 0XF1 0X0c 0X00 0X0c 0X7E

Stop Action=0XF1 0XF1 0X0c 0X00 0X0c 0X7E

阅读功能示例:

当前高度(1000mm-0x03E8) 0XF2 0XF2 0X01 0X02 0X03 0XE8 0XEE 0X7E

Current height(1000mm-0x03E8) 0XF2 0XF2 0X01 0X02 0X03 0XE8 0XEE 0X7E

(数据"中有两个字节，因此数据长度"为0x02；校验和" = 0x01 + 0x02 + 0x03 + 0xE8 = 0xEE)

(there is two bytes in ‘Data’,so ‘Data Length’ is 0x02;‘Checksum’= 0x01 + 0x02 +0x03 +0xE8 = 0xEE)

期望读取功能可以提供当前的高度信息，而写入功能则可以控制设备.

Expecting the read functionality to give the current height info and write functionality to be able to control the device.

版本，操作系统和硬件:

SerialPort @ ^ 8.0.7

SerialPort@ ^8.0.7

Node.js v10.16.0

Node.js v10.16.0

Windows

硬件和芯片组? COM4

Hardware and chipset? COM4

FTDIBUS \ VID_0403 + PID_6001 + AB0JIYQTA \ 0000

FTDIBUS\VID_0403+PID_6001+AB0JIYQTA\0000

FTDI

推荐答案

创建读取行解析器表明消息以\ n终止，但是您的写操作不包含消息，因此可以解释为什么命令无法到达设备.

Creating a read-line parser suggests that messages are terminated by \n, but your write does not include one, so that could explain why commands are not getting to the device.

对于读取，如果要使用读取行解析器，则需要将serialPort传递给它，然后侦听解析器中的数据，例如:

For the reads, if you want to use the read-line parser, you need to pipe the serialPort to it, then listen for data from the parser, e.g.:

serialPort.pipe(parser);

parser.on('data', (data) => {
  console.log(data)
})

注意:数据将是缓冲区

您可以跳过解析器并直接调用read.我想你尝试过了.医生说:

You could skip the parser and call read directly. I assume you tried that. Docs say:

如果没有数据可读取，则返回null.

If no data is available to be read, null is returned.

https://serialport.io/docs/api-stream#serialport-read

因此，可能是办公桌仅在收到消息后才输出数据.

So, it could be that the desk only outputs data after a message is received.

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