serrrggggeee-Arbyte-Quint-B-M4D3A-H61 serrrggggeee # echo b'Q1\r' > /dev/ttyS0
serrrggggeee-Arbyte-Quint-B-M4D3A-H61 serrrggggeee # cat < /dev/ttyS0
^C

ser = serial.Serial("/dev/ttyS0", baudrate=2400)
ser.open()
ser.write(b"Q1\r")
print(ser.readline(eol=serial.CR))

#! /usr/bin/env python
# coding: utf-8
 
import serial
ser = serial.Serial("/dev/ttyS0", baudrate=2400)
ser.open()
ser.write(b"Q1\r")
print(ser.readline(eol=serial.CR))

serial.serialutil.SerialException: Port is already open

ser = serial.Serial("/dev/ttyS0", baudrate=2400)
#ser.open()
ser.write(b"Q1\r")
print(ser.readline(eol=serial.CR))

serrrggggeee-Arbyte-Quint-B-M4D3A-H61 serrrggggeee # python port_n.py
Traceback (most recent call last):
  File "port_n.py", line 8, in <module>
    print(ser.readline(eol=serial.CR))
TypeError: readline() takes no keyword arguments

ser.write(b"Q1\r")
print(ser.readline())

serrrggggeee-Arbyte-Quint-B-M4D3A-H61 serrrggggeee # python port_n.py
^CTraceback (most recent call last):
  File "port_n.py", line 8, in <module>
    print(ser.readline())
  File "/usr/lib/python2.7/dist-packages/serial/serialposix.py", line 446, in read
    ready,_,_ = select.select([self.fd],[],[], self._timeout)
KeyboardInterrupt
serrrggggeee-Arbyte-Quint-B-M4D3A-H61 serrrggggeee # 

ser.read(1)

ser = serial.Serial("/dev/ttyS0", baudrate=2400)
    #ser.open()
    ser.write(b"F\r")
    ups= ser.read(10)
    ser.write(b"Q1\r")
    ups1= ser.read(47)
    ser.write(b"D\r")
    ups2= ser.read(14)

 float(ups1[1:6])