Urgent:Serial Port Read/Write
Hi all,I'm new to python and facing issue using serial in python.I'm facing the
below error
ser.write(port,command)NameError: global name 'ser' is not defined
Please find the attached script and let me know whats wrong in my script and
also how can i read data from serial port for the same script.
Best Regards,Chandan.
import time
import os
import serial
import glob
ER_Address = [[0x0A,0x01,0x08,0x99,0xBB,0xBB,0xBB,0xBB,0xBB,0xBB,0xBB]]
Function Name: RunSequence
Function Description:
-
A RunSequence function has Multiple calls to the RunSuite function, each call
is a single testcase consisting of all the parameters
required by the RunTesSuite.
-
def WriteSerialData(command):
ser.write(port,command)
def SendPacket(Packet):
str = chr(len(Packet)) + Packet #Concatenation of Packet with the
PacketLength
print str
WriteSerialData(str)
def CreateFrame(Edata):
evt = chr(0x12)
evt = evt + chr(Edata[0])
for i in range (1, len(Edata)):
evt = evt + chr(Edata[i])
return evt
def SetRequest(data):
print data
new = []
new = sum(data, [])
Addr = CreateFrame(new)
SendPacket(Addr)
print SendPacket Done
ReadPacket()
def OpenPort(COMPort,BAUDRATE):
This function reads the serial port and writes it.
comport=COMPort
BaudRate=BAUDRATE
try:
ser = serial.Serial(
port=comport,
baudrate=BaudRate,
bytesize=serial.EIGHTBITS,
parity=serial.PARITY_NONE,
stopbits=serial.STOPBITS_ONE,
timeout=10,
xonxoff=0,
rtscts=0,
dsrdtr=0
)
if ser.isOpen():
print Port Opened
ser.write(Chandan)
string1 = ser.read(8)
print string1
return ser
else:
print Port CLosed
ser.close()
return 3
except serial.serialutil.SerialException:
print Exception
ser.close()
if __name__ == __main__:
CurrDir=os.getcwd()
files = glob.glob('./*pyc')
for f in files:
os.remove(f)
OpenPort(26,9600)
SetRequest(ER_Address)
#SysAPI.SetRequest('ER',ER_Address)
print Test Scripts Execution complete
--
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Re: Urgent:Serial Port Read/Write
On Fri, May 10, 2013 at 1:35 AM, chandan kumar chandan_...@yahoo.co.in wrote: Hi all, I'm new to python and facing issue using serial in python.I'm facing the below error ser.write(port,command) NameError: global name 'ser' is not defined Please find the attached script and let me know whats wrong in my script and also how can i read data from serial port for the same script. You're assigning to 'ser' inside OpenPort(), but then trying to use it in WriteSerialData(). You'll need to declare 'global ser' in OpenPort to make this work. Alternatively, you may want to cut down on the number of functions you have, since they're called in only one place anyway and have to share state. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Urgent:Serial Port Read/Write
On Thu, 09 May 2013 23:35:53 +0800, chandan kumar wrote:
Hi all,I'm new to python and facing issue using serial in python.I'm
facing the below error
ser.write(port,command)NameError: global name 'ser' is not defined
Please find the attached script and let me know whats wrong in my script
and also how can i read data from serial port for the same script.
[snip]
if __name__ == __main__:
CurrDir=os.getcwd()
files = glob.glob('./*pyc')
for f in files:
os.remove(f)
OpenPort(26,9600)
SetRequest(ER_Address)
#SysAPI.SetRequest('ER',ER_Address)
print Test Scripts Execution complete
What kind of 'port' is 26? Is that valid on your machine? My guess is
that ser is NULL (because the open is failing, likely due to the port
selection), leading to your subsequent problems.
HTH..
--
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Re: Urgent:Serial Port Read/Write
On 09/05/2013 16:35, chandan kumar wrote:
Hi all,
I'm new to python and facing issue using serial in python.I'm facing the
below error
*ser.write(port,command)*
*NameError: global name 'ser' is not defined*
*
*
Please find the attached script and let me know whats wrong in my script
and also how can i read data from serial port for the same script.
Best Regards,
Chandan.
RunScripts.py
import time
import os
import serial
import glob
ER_Address = [[0x0A,0x01,0x08,0x99,0xBB,0xBB,0xBB,0xBB,0xBB,0xBB,0xBB]]
Function Name: RunSequence
Function Description:
-
A RunSequence function has Multiple calls to the RunSuite function, each call
is a single testcase consisting of all the parameters
required by the RunTesSuite.
-
def WriteSerialData(command):
'ser' isn't a local variable (local to this function, that is), nor is
it a global variable (global in this file).
ser.write(port,command)
def SendPacket(Packet):
str = chr(len(Packet)) + Packet #Concatenation of Packet with the
PacketLength
print str
WriteSerialData(str)
def CreateFrame(Edata):
It's more efficient to build a list of the characters and then join
them together into a string in one step than to build the string one
character at a time.
Also, indexing into the list is considered 'unPythonic'; it's much
simpler to do it this way:
return chr(0x12) + .join(chr(d) for d in Edata)
evt = chr(0x12)
evt = evt + chr(Edata[0])
for i in range (1, len(Edata)):
evt = evt + chr(Edata[i])
return evt
def SetRequest(data):
print data
new = []
new = sum(data, [])
Addr = CreateFrame(new)
SendPacket(Addr)
print SendPacket Done
ReadPacket()
def OpenPort(COMPort,BAUDRATE):
This function reads the serial port and writes it.
comport=COMPort
BaudRate=BAUDRATE
try:
ser = serial.Serial(
port=comport,
baudrate=BaudRate,
bytesize=serial.EIGHTBITS,
parity=serial.PARITY_NONE,
stopbits=serial.STOPBITS_ONE,
timeout=10,
xonxoff=0,
rtscts=0,
dsrdtr=0
)
if ser.isOpen():
print Port Opened
ser.write(Chandan)
string1 = ser.read(8)
print string1
This function returns either ser ...
return ser
else:
print Port CLosed
ser.close()
... or 3 ...
return 3
except serial.serialutil.SerialException:
print Exception
ser.close()
... or None!
if __name__ == __main__:
CurrDir=os.getcwd()
files = glob.glob('./*pyc')
for f in files:
os.remove(f)
OpenPort returns either ser or 3 or None, but the result is just
discarded.
OpenPort(26,9600)
SetRequest(ER_Address)
#SysAPI.SetRequest('ER',ER_Address)
print Test Scripts Execution complete
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Re: Urgent:Serial Port Read/Write
On Fri, May 10, 2013 at 1:35 AM, chandan kumar chandan_...@yahoo.co.in wrote: Please find the attached script and let me know whats wrong in my script and also how can i read data from serial port for the same script. Don't do this: except serial.serialutil.SerialException: print Exception ser.close() Just let it propagate up and show you a traceback. There is absolutely no value in suppressing an exception only to print an unhelpful message. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
