Python3 双向串行通信:读入数据 [英] Python3 Two-Way Serial Communication: Reading In Data
问题描述
我正在尝试通过 Python3 建立双向通信.有一个激光测距仪插入我的一个 USB 端口,我想向它发送/接收命令.我有一张可以发送的命令以及它们会返回什么,所以这部分已经存在了.
I am trying to establish a two-way communication via Python3. There is a laser range finder plugged into one of my USB ports and I'd like to send/receive commands to that. I have a sheet of commands which can be sent and what they would return, so this part is already there.
我需要的是一种实时进行的便捷方式.到目前为止,我有以下代码:
What I need is a convenient way to do it in real-time. So far I have the following code:
import serial, time
SERIALPORT = "/dev/ttyUSB0"
BAUDRATE = 115200
ser = serial.Serial(SERIALPORT, BAUDRATE)
ser.bytesize = serial.EIGHTBITS #number of bits per bytes
ser.parity = serial.PARITY_NONE #set parity check: no parity
ser.stopbits = serial.STOPBITS_ONE #number of stop bits
ser.timeout = None #block read
ser.xonxoff = False #disable software flow control
ser.rtscts = False #disable hardware (RTS/CTS) flow control
ser.dsrdtr = False #disable hardware (DSR/DTR) flow control
ser.writeTimeout = 0 #timeout for write
print ("Starting Up Serial Monitor")
try:
ser.open()
except Exception as e:
print ("Exception: Opening serial port: " + str(e))
if ser.isOpen():
try:
ser.flushInput()
ser.flushOutput()
ser.write("1\r\n".encode('ascii'))
print("write data: 1")
time.sleep(0.5)
numberOfLine = 0
while True:
response = ser.readline().decode('ascii')
print("read data: " + response)
numberOfLine = numberOfLine + 1
if (numberOfLine >= 5):
break
ser.close()
except Exception as e:
print ("Error communicating...: " + str(e))
else:
print ("Cannot open serial port.")
所以在上面的代码中,我发送了1",它应该触发激光探测器的getDistance()"函数并返回以毫米为单位的距离.我在 Putty 上试过这个,它可以工作,返回最多 4 位数字的距离.但是,当我启动上面的 Python 脚本时,我的输出只有以下内容:
So in the above code I am sending "1" which should trigger "getDistance()" function of the laser finder and return the distance in mm. I tried this on Putty and it works, returns distances up to 4 digits. However, when I launch the above Python script, my output is only the following:
Starting Up Serial Monitor
Exception: Opening serial port: Port is already open.
write data: 1
read data:
它永远存在.没有读取数据或任何内容.
and it goes forever. There is no read data or whatsoever.
我哪里弄错了?
推荐答案
显然更简单的代码版本解决了这个问题.
Apparently much more simpler version of the code solved the issue.
import serial
import time
ser = serial.Serial('/dev/ttyUSB0', 115200, timeout = 1) # ttyACM1 for Arduino board
readOut = 0 #chars waiting from laser range finder
print ("Starting up")
connected = False
commandToSend = 1 # get the distance in mm
while True:
print ("Writing: ", commandToSend)
ser.write(str(commandToSend).encode())
time.sleep(1)
while True:
try:
print ("Attempt to Read")
readOut = ser.readline().decode('ascii')
time.sleep(1)
print ("Reading: ", readOut)
break
except:
pass
print ("Restart")
ser.flush() #flush the buffer
根据需要输出:
Writing: 1
Attempt to Read
Reading: 20
Restart
Writing: 1
Attempt to Read
Reading: 22
Restart
Writing: 1
Attempt to Read
Reading: 24
Restart
Writing: 1
Attempt to Read
Reading: 22
Restart
Writing: 1
Attempt to Read
Reading: 26
Restart
Writing: 1
Attempt to Read
Reading: 35
Restart
Writing: 1
Attempt to Read
Reading: 36
这篇关于Python3 双向串行通信:读入数据的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!