Python-无法使用串行命令

Question

Trying to send commands to the hardware: Laser on and off. But Python is failing and the hardware never getting the command.

Command list:

ss.py:

import serial
ser = serial.Serial('/dev/tty.usbserial', serial.EIGHTBITS, serial.PARITY_NONE, serial.STOPBITS_ONE)
print(ser.name)
# if i add ' then also error
ser.write(\xA0h\xC1h\x01\x00h\xSt.\xAFh)

ser.close()

On execute error occure:

  File "ss.py", line 5
    ser.write(\xA0h\xC1h\x01\x00h\xSt.\xAFh)
                                           ^
SyntaxError: unexpected character after line continuation character

or

Error:

$ python ss.py 
Traceback (most recent call last):
  File "ss.py", line 3, in <module>
    ser = serial.Serial('/dev/tty.usbserial', serial.EIGHTBITS, serial.PARITY_NONE, serial.STOPBITS_ONE)
  File "/Library/Python/2.7/site-packages/serial/serialutil.py", line 220, in __init__
    self.bytesize = bytesize
  File "/Library/Python/2.7/site-packages/serial/serialutil.py", line 306, in bytesize
    raise ValueError("Not a valid byte size: {!r}".format(bytesize))
ValueError: Not a valid byte size: 'N'

Answer 1

I suspect that you need to send the commands one at a time, rather than as a single string.

for command in [b'0xA0h', b'0xC1h', b'0x01', b'0x00h', b'0xSt', b'0xAFh']:
    ser.write(command)

Notice that I have also altered the beginning of each subcommand to indicate that it is a hex value.

========EDIT========

Looking at the command list in your question, I wonder if you have used the "Switch on" command to make sure the system is on?

I also see that it is possible to send a string to query the device. Have you tried that?