通过串行端口从Velleman k8090读取和写入数据，不使用Python 3

各位,

我有一个Velleman k8090中继板，我试图从中读取和写入一些数据（我在下面的链接中找到了代码源：）。 我可以用python-2.x做得很好，但是当我切换到python-3.x时，它在linux（ubuntu）和windows（10）上都不再工作了。 它没有显示一些错误或类似的内容，但继电器没有切换。我认为它并没有执行（读或写）正确的假设。Python3在读/写过程中出现了一些错误，我不明白。请帮忙！ 下面是我的python代码和终端输出

代码

#!/usr/bin/python3

import serial
import time

# Source: https://stackoverflow.com/questions/17862862/python-read-data-via-serial-port-from-velleman-k8090
# https://iot4beginners.com/how-to-read-and-write-from-serial-port-using-raspberry-pi/

COM_PORT = 'COM4'
class Velleman8090:
    def __init__(self, port=COM_PORT):
        self.port = port
        self.baud_rate = 19200
        self.data_bits = serial.EIGHTBITS
        self.parity = serial.PARITY_NONE
        self.stop_bits = serial.STOPBITS_ONE
        self.flow_control = False
    def open_device(self):
        self.talk = serial.Serial(self.port, self.baud_rate, self.data_bits, self.parity, self.stop_bits, timeout=0.5, write_timeout=2)
        print("open")
    def firmware_version(self):
        cmd = 0x11
        mask = 0xff
        param1 = 0x00
        param2 = 0x00
        #data = b'\x04P\x11\xff\x00\xa8\x0f'
        #data = bytearray(b'\\x04\\x11\\xff\\x00\\x00\\xec\\x0f')
        data = packet(cmd, mask, param1, param2)
        print(data)
        self.talk.flush()
        self.talk.write(data.encode())
        
        print("correct")
        
        output = self.talk.read(7)
        print (output)
        output = output.encode('hex')  #converts the strange characters to hex
        output = output.hex() # Python 3
        print (output)
        
    def close_device(self):
        self.talk.close()
        print("close")
def chksum(cmd,msk,p1,p2):
    checksum = (((~(0x04 + cmd + msk + p1 + p2)) + 0x01) & 0xff)
    print("checksum %s" % (hex(checksum)))
    return checksum

def packet(cmd,msk,p1,p2):
    print("packet")
    return str(bytearray([0x04, cmd, msk, p1, p2, chksum(cmd, msk, p1, p2), 0x0f]))

def main():
    vm8090 = Velleman8090()
    vm8090.open_device()
    vm8090.firmware_version()
    vm8090.close_device()
if __name__ == "__main__":
    main() 

终端输出（窗口外壳）

PS C:\Users\atc\Desktop> python .\testVellman.py
open
packet
checksum 0xec
bytearray(b'\x04\x11\xff\x00\x00\xec\x0f')
correct
b''
close
PS C:\Users\atc\Desktop>