General Modbus master functions. More...
Go to the source code of this file.
Data Structures | |
| struct | modbusMasterUserFunction |
| Associates user-defined response parser function with the function ID. More... | |
| struct | modbusMaster |
| Represents Modbus master device's status and configuration. More... | |
Typedefs | |
| typedef struct modbusMasterUserFunction | ModbusMasterUserFunction |
| Associates user-defined response parser function with the function ID. More... | |
| typedef struct modbusMaster | ModbusMaster |
| Represents Modbus master device's status and configuration. More... | |
Functions | |
| ModbusError | modbusParseResponse (ModbusMaster *status) |
| Interprets the incoming response frame located in the master structure. More... | |
| ModbusError | modbusMasterInit (ModbusMaster *status) |
| Performs initialization of the ModbusMaster structure. More... | |
| ModbusError | modbusMasterEnd (ModbusMaster *status) |
| Frees memory used by the ModbusMaster structure, previously initialized with modbusMasterInit. More... | |
Detailed Description
General Modbus master functions.
- Note
- This header file is suitable for C++
Typedef Documentation
◆ ModbusMaster
| typedef struct modbusMaster ModbusMaster |
Represents Modbus master device's status and configuration.
◆ ModbusMasterUserFunction
| typedef struct modbusMasterUserFunction ModbusMasterUserFunction |
Associates user-defined response parser function with the function ID.
Function Documentation
◆ modbusMasterEnd()
| ModbusError modbusMasterEnd | ( | ModbusMaster * | status | ) |
Frees memory used by the ModbusMaster structure, previously initialized with modbusMasterInit.
- Parameters
-
status The master structure to be freed
- Returns
- A ModbusError error code
◆ modbusMasterInit()
| ModbusError modbusMasterInit | ( | ModbusMaster * | status | ) |
Performs initialization of the ModbusMaster structure.
- Parameters
-
status The master structure to be initialized
- Returns
- A ModbusError error code
◆ modbusParseResponse()
| ModbusError modbusParseResponse | ( | ModbusMaster * | status | ) |
Interprets the incoming response frame located in the master structure.
Calling this function results in processing the frame located in ModbusMaster::response. The received data will be located in ModbusMaster::data or ModbusMaster::exception if slave has responded with an exception frame.
Firstly, this function resets and freed data previously stored in ModbusMaster::exception and ModbusMaster::data.
Afterwards, the frame is validated using modbusCRC() function. If it's not consistent, it's discarded at this point and MODBUS_ERROR_PARSE is returned.
Then, array of user-defined functions is searched. It is important to mention that, user functions override built-in functions. That means, one can disable specific function by simply inserting NULL pointer into the array,
If matching function is found among user-defined or built-in functions, the modbusParseResponse() returns the exact error code the parsing function had returned. Otherwise, MODBUS_ERROR_PARSE is returned.
- Parameters
-
status The master structure to work on
- Returns
- A ModbusError error code
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