Could not send serial communication data

Question

I have a Digi zigbee device which is configured (Python code) to send data serially through a COM port. On the other end of the serial communication there is an embedded board which receives data.

After I connect digi (sending data) to the embedded board, the digi after sending few data reboots (COM PORT closes). But the embedded board remains alive throughout the whole period.

This embedded board has a software through which I can see its logs. When I checked the logs, I received some data (three sensor values) and the digi device dies. I don't know where the problem is occuring. Is it with the digi-zigbee device which is sending data or PYTHON CODE(used in digi device) or the embedded board which is receiving the data?

Here is just a part of python source code :

open()

flushInput()

flushOutput()

while True:

    # Retrieve a sample reading from the LT
    io_sample = xbee.ddo_get_param(sensor_address, "is")  
    light = parseIS(io_sample)["AI1"]
    temp  = parseIS(io_sample)["AI2"]
    hum = parseIS(io_sample)["AI3"]
    mVanalog = (float(temp)  / 1023.0) * 1200.0
    temp_C = (mVanalog - 500.0)/ 10.0 # - 4.0
    lux = (float(light)  / 1023.0) * 1200.0
    print "hum:%f" %hum
    sync=254
    temp=round(temp_C,2)
    light=round(lux,2)
    no_temp = len(str(temp))
    no_light = len(str(light))
    total_length=no_temp+no_light+3+3
    if total_length<256:
      low_byte=total_length
      high_byte=0
    else:
      low_byte=total_length%256
      high_byte=high_byte/256
    msg_id_low=0
    msg_id_high=0
    checksum=low_byte+high_byte+msg_id_low+msg_id_high+ord('#')+ord(':')+ord(',')
    t=str(temp)
    for c in t: 
      if c == '.':
        checksum+=ord('.')  
      else:
        checksum+=ord(c)
    t=str(light)
    for c in t:
      if c == '.':
        checksum+=ord('.')  
      else:
        checksum+=ord(c)
    checksum=256-(checksum%256)
    if checksum == 256:
      checksum=0
    print "Checksum Value after applying mod operator:%d" %checksum
    packet=str(chr(254))+str(chr(low_byte))+str(chr(high_byte))+str(chr(msg_id_low))+str(chr(msg_id_high))+str('#')+str(temp)+str(':')+str(light)+str(',')+str(chr(checksum))

    print "packet:%s" %packet
    bytes_written = write(packet)
    print "bytes_written : %s value : %s" %(bytes_written,packet)
    time.sleep(5)

This Code gets the temperature and light value from sensors and converts it into a packet(sync,checksum etc) to be send to the embedded board .

How do you think anyone will know without seeing the code or the logs? — Mark Setchell, May 27 '14 at 07:05
You can run the code using python debbuger option and execute step by step to see the result. From which you can find out. I am guessing you have prompt for your device to run the python script using debugger option. Also post some logs having some meaningful messages so that we can tell you whether its python error. — , May 27 '14 at 07:10
Also You can write more messages(at every or most steps of code) to logs to see till what point the code is working fine. — , May 27 '14 at 07:20

Could not send serial communication data

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