First Steps /help

[brandonfwl]

I tried to run:

//
from pymodbus.client.sync import ModbusTcpClient

client = ModbusTcpClient('myStaticIP, port=myPort')
client.connect()
rr = client.connect()
print rr
client.write_coil(1, True)
result = client.read_coils(1,1)
print result.bits[0]
client.close()
//

Output is as follows:
//
True
Traceback (most recent call last):
File "./test.py", line 11, in
print result.bits[0]
AttributeError: 'NoneType' object has no attribute 'bits'
//

Tried on Ubuntu 12.10, Linux Mint 15 and BeagleBone (Black). All different boxes, with good ping responses from Modbus client. Modbus client is an IDEC FC5A-D12 running as Modbus TCP Slave.

Any help would be great!

[bashwork]

So it appears that you are not getting anything back from the device. Could you enable logging and post that here so I can see what is going on?

[brandonfwl]

DEBUG:pymodbus.transaction:Running transaction 1
DEBUG:pymodbus.transaction:Transaction failed. (timed out)
DEBUG:pymodbus.transaction:
DEBUG:pymodbus.transaction:getting transaction 1
Traceback (most recent call last):
File "./test.py", line 11, in
print result.bits[0]
AttributeError: 'NoneType' object has no attribute 'bits'

[bashwork]

So your device is not responding. Is there anyway that you can test a basic read with the following tool and see if you can get a successful coil read over TCP:

http://www.modbusdriver.com/modpoll.html

[brandonfwl]

I was able to get a successful coil read with the modpoll tool using the default command listed:

'modpoll -c 5 -r 100 -p 50002 -m tcp xxx.xx.x.xx'

I manually set the port to 50002 as the default 502 is trouble with my linux box.

[bashwork]

Great so your device is fine, the following test should pass as long as you
have permission to write to the device::

https://gist.github.com/bashwork/f6c1c67375b9fd88de22

On Tue, Jul 9, 2013 at 3:16 PM, brandonfwl [email protected] wrote:

I was able to get a successful coil read with the modpoll tool using the
default command listed:

'modpoll -c 5 -r 100 -p 50002 -m tcp xxx.xx.x.xx'

I manually set the port to 50002 as the default 502 is trouble with my
linux box.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/25#issuecomment-20681197
.

[brandonfwl]

client connected: True
DEBUG:pymodbus.transaction:Running transaction 1
DEBUG:pymodbus.transaction:Transaction failed. (timed out)
DEBUG:pymodbus.transaction:
DEBUG:pymodbus.transaction:getting transaction 1
Traceback (most recent call last):
File "./pytest.py", line 15, in
assert(rq != None)
AssertionError

[brandonfwl]

I did have a question about this line : 'assert(rq.function_code < 0x80)'

What does the 0x80 function code do? As I understand the function code to 'write single register' is 0x05. Is the 0x80 an offset for something? Please excuse my lack of knowledge on this, I'm still learning.

[bashwork]

Any function code that is greater than 0x80 is an error response, so hopefully all returned messages have a function code below 0x80. What I am wondering is if your device is just slow to response and thus timing out. Can you attempt to copy the advice from this issue: #21

[brandonfwl]

would that be in 'transaction.py' in pymodules?

would you use

import time

time.sleep()?

what's a good starting value?

[brandonfwl]

Tried a few different timing schema to delay between send() & recv(1024). Same result as before. Edke indicates that he modified the function but doesn't indicate in what way.

[mesias]

I've modified and printed the result of recv(1024) when i got trouble. Any
data are received ?

On Tue, Jul 9, 2013 at 8:05 PM, brandonfwl [email protected] wrote:

Tried a few different timing schema to delay between send() & recv(1024).
Same result as before. Edke indicates that he modified the function but
doesn't indicate in what way.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/25#issuecomment-20711758
.

Alejandro Mesias André Nebra Perez
Java/Python/Js/Something else Developer
Twitter: @meszias
Linux User #442506

Campinas - SP - Brasil - South America

[brandonfwl]

No data received. Same result as before.

[brandonfwl]

Think I've got somewhere with this. Here is the current DEBUG output:

client connected: True
DEBUG:pymodbus.transaction:Running transaction 1
DEBUG:pymodbus.transaction:����
DEBUG:pymodbus.transaction:0x0 0x1 0x0 0x0 0x0 0x6 0x1 0x5 0x0 0x5 0xff 0x0
DEBUG:pymodbus.factory:Factory Response[5]
DEBUG:pymodbus.transaction:adding transaction 1
DEBUG:pymodbus.transaction:getting transaction 1
DEBUG:pymodbus.transaction:Running transaction 2
DEBUG:pymodbus.transaction:������
DEBUG:pymodbus.transaction:0x0 0x2 0x0 0x0 0x0 0x4 0x1 0x1 0x1 0x1
DEBUG:pymodbus.factory:Factory Response[1]
DEBUG:pymodbus.transaction:adding transaction 2
DEBUG:pymodbus.transaction:getting transaction 2

For some reason the PLC I'm using does require the UnitID to specified. In 'constants' the default is 0, while my test device ID is slave 1. Changed the 0 to a 1 and this is what I have. I ended up removing the time delay between send() and recv in TransactionManager (connection does not appear to be slow from the device). I'm hoping this is a good response.

[brandonfwl]

Oh, I did want to reference the device that I'm using. Here is the manual for the FC5A Micro Smart Pentra Basic and Advanced http://us.idec.com/Common/Download.aspx?d=30 and the Modbus TCP point of interest is on page 33-9, where it does list that Unit ID is required.

[bashwork]

Awesome, I'm glad you got things working. I was going to suggest the slave
id be changed, but I had read (apparently the wrong) application note that
said it didn't matter. Anyways, you can specify the unit as a request
parameter::

client.read_coils(0x01, count=2, unit=1)

I will make sure to better illuminate these options in the examples; here
is the relevant documentation if you are interested:

https://pymodbus.readthedocs.org/en/latest/library/client-common.html

On Wed, Jul 10, 2013 at 3:10 PM, brandonfwl [email protected]:

Oh, I did want to reference the device that I'm using. Here is the manual
for the FC5A Micro Smart Pentra Basic and Advanced
http://us.idec.com/Common/Download.aspx?d=30 and the Modbus TCP point of
interest is on page 33-9, where it does list that Unit ID is required.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/25#issuecomment-20748886
.

[brandonfwl]

So, am I correct in assuming that the response output was a good one?

[brandonfwl]

Another question. If, in my case the Unit ID is required and I have more that one slave; is there a way to address the unit ID when the object is created rather than changing the 'constants'?

[brandonfwl]

Sorry, didn't see that you already answered the above question with the client.read example.

[bashwork]

So are you good to go brandon or do I need to keep this issue open?

[brandonfwl]

Think I'm good to go for the time being. Thanks for the awesome work!