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ljean / modbus-tk

Create Modbus app easily with Python
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Modbus RTU slave implementation #87

Open zoliknemet opened 7 years ago

zoliknemet commented 7 years ago

I am trying to implement Modbus RTU slave and I have a problem with connecting client to that server. I did as in an example (rtuslave_example.py), but the client is always returning Timeout Error.

I am using this client: http://www.modbustools.com/modbus_poll.html It is python 2.7 and TCP slave works fine (also from examples)

Do you have any suggestions on how to connect third party client to your Modbus RTU server? Also, I am using Free Vritual Serial Ports https://freevirtualserialports.com/

ljean commented 7 years ago

I think that you may have a communication error due to something wrong in the serial link : maybe a problem with the cable or the communication settings (parity, baud rate…)

I hope it helps

Le 14 août 2017 à 19:10, Zolik notifications@github.com a écrit :

I am trying to implement Modbus RTU slave and I have a problem with connecting client to that server. I did as in an example (rtuslave_example.py), but the client is always returning Timeout Error.

I am using this client: http://www.modbustools.com/modbus_poll.html http://www.modbustools.com/modbus_poll.html It is python 2.7 and TCP slave works fine (also from examples)

Do you have any suggestions on how to connect third party client to your Modbus RTU server?

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rdpoor commented 5 years ago

@zoliknemet : Take a look at #67 -- this may be the cause of your problems. The Modbus RTU master assumes that the slave device will respond within 3.5 byte periods, which is often too strict.