Pymodbus RTU AttributeError

[Ionut Dinu]

Hy,
     I used Pymodbus library to acquire data from a server, via RTU. i'll put on this post my pyscript code, noting that same script works perfectly a entire day, until i reboot my linux kernel.

SAMPLE PYTHON SCRIPT:
 
import pymodbus
import serial
import json
from pymodbus.pdu import ModbusRequest
from pymodbus.client.sync import ModbusSerialClient as ModbusClient #initialize a serial RTU client instance
from pymodbus.transaction import ModbusRtuFramer

client= ModbusClient(method = "rtu", port="/dev/ttyO1", baudrate = 19200, stopbits = 1, parity = 'N', bytesize= 8)
#connect to the serial modbus server
connection = client.connect()
#print connection

#starting add, num of reg to read, slave unit.
result= client.read_holding_registers(51457,1,unit= 0x05)
print(result.registers[0])

#closes the underlying socket connection
client.close()

                   My AttributeError look's like that, i dont't know how to fix it.

SMAPLE AttributeError

Traceback (most recent call last):
  File "test_rtu.py", line 27, in <module>
    print(result.registers[0])
AttributeError: 'NoneType' object has no attribute 'registers'
                       
                

[ozzyuh .]

Hi,

try and use "print(result.registers)"

--
You received this message because you are subscribed to the Google Groups "pymodbus" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pymodbus+u...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Ionut Dinu]

Hello,
   I've tried your suggestion: print(result.registers) or print result.registers, but no positive result. My error is the same. Thanks for your help!

[ozzyuh .]

Hi,

I cant figure what the error means exactly but,

Try and using regular decimal value for unit variable.

[Ionut Dinu]

Hello,
 
       Thanks, once again for your help. I resolved my error, it was a port error.

[Georgia Tech Research Institute]

Hi Ionut,

I'm getting the same error you did.  Can you tell me how you fixed the port issue?

Thanks!

[Moghul Mansoor]

Hey guys, 

I am getting the same error. Any idea about what I should do with the port?

Thanks!

[Leon Lee]

Sir, I'm also have the same problem with you , I think maybe I plug with the wrong wire or wrong place
Can you show me or teach me how you fix it~!!!!!
Please!!!!!!

[Akash Agarwal]

result is a None type object here. Check it before getting it's attribute values

--

[Leon Lee]

Hey sir, I got a same error, but how did you solved it?