python串行设备通信问题名称“ s”未定义

问题描述

我有一个可以与之通信的串行设备。我决定将代码放入类模块并进行构建。我遇到了有关串行端口的问题。...

错误：

从雷达进口RD

m = RD（'S06'）

m.KLD2Setup（）

回溯（最近通话最近一次）：

文件“”，第
行第1行
KLD2Setup中的文件“ /home/pi/my_Python/Radar/radar.py”，第23行
s.write(self.cmd.encode())
NameError：名称“ s”未定义

如果我调用python在没有类的文件中创建串行端口等，则此代码块有效

#! /usr/bin/python
 
class RD():
    '''RFB K-LD2 module'''      
    def __init__(self,command):
        '''initialize'''
        self.cmd = command
        from serial import Serial
        s = Serial('/dev/ttyS0',38400)
 
    def KLD2Setup(self):
        '''use this method for sending commands and receiving data'''
        self.cmd = '$' + self.cmd + '\r'
        if (self.cmd[1] in {"S","D","R","W","T"}):
            k = 8
        elif (self.cmd[1] in {"F","A"}):
            k = 10
        elif (self.cmd[1] == "C"):  
            k = input ("Enter the number of bytes? ")   
        else: 
            k = 0
        if (k):
            s.write(self.cmd.encode())
            print((s.read(int(k)).rstrip()).lstrip(b'@'))

解决方法

这是一个范围问题，

更改：

第9行：self.s = Serial('/dev/ttyS0',38400) 第23行：self.s.write(self.cmd.encode())

在 init 中创建一个local，然后尝试在方法KLD2Setup中使用local。当您正在使用一个类时，您需要使用self.s

#! /usr/bin/python
from serial import Serial
 
class RD():
    '''RFB K-LD2 module'''      
    def __init__(self,command):
        '''initialize'''
        self.cmd = command
        self.s = Serial('/dev/ttyS0',38400)
  
    def KLD2Setup(self):
        '''use this method for sending commands and receiving data'''
        self.cmd = '$' + self.cmd + '\r'
        if (self.cmd[1] in {"S","D","R","W","T"}):
            k = 8
        elif (self.cmd[1] in {"F","A"}):
            k = 10
        elif (self.cmd[1] == "C"):  
            k = input ("Enter the number of bytes? ")   
        else: 
            k = 0
        if (k):
            self.s.write(self.cmd.encode())
            print((self.s.read(int(k)).rstrip()).lstrip(b'@'))

python serial-port