factory
— Request/Response Decoders¶
API Documentation¶
Modbus Request/Response Decoder Factories¶
The following factories make it easy to decode request/response messages. To add a new request/response pair to be decodeable by the library, simply add them to the respective function lookup table (order doesn’t matter, but it does help keep things organized).
Regardless of how many functions are added to the lookup, O(1) behavior is kept as a result of a pre-computed lookup dictionary.
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class
pymodbus.factory.
ServerDecoder
¶ Request Message Factory (Server)
To add more implemented functions, simply add them to the list
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__init__
()¶ Initializes the client lookup tables
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_helper
(data)¶ This factory is used to generate the correct request object from a valid request packet. This decodes from a list of the currently implemented request types.
Parameters: data – The request packet to decode Returns: The decoded request or illegal function request object
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decode
(message)¶ Wrapper to decode a request packet
Parameters: message – The raw modbus request packet Returns: The decoded modbus message or None if error
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lookupPduClass
(function_code)¶ Use function_code to determine the class of the PDU.
Parameters: function_code – The function code specified in a frame. Returns: The class of the PDU that has a matching function_code.
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class
pymodbus.factory.
ClientDecoder
¶ Response Message Factory (Client)
To add more implemented functions, simply add them to the list
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__init__
()¶ Initializes the client lookup tables
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_helper
(data)¶ This factory is used to generate the correct response object from a valid response packet. This decodes from a list of the currently implemented request types.
Parameters: data – The response packet to decode Returns: The decoded request or an exception response object
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decode
(message)¶ Wrapper to decode a response packet
Parameters: message – The raw packet to decode Returns: The decoded modbus message or None if error
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lookupPduClass
(function_code)¶ Use function_code to determine the class of the PDU.
Parameters: function_code – The function code specified in a frame. Returns: The class of the PDU that has a matching function_code.
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