This class provides a Modbus client. More...

#include <Modbus.h>

Classes
struct	DeviceInfo

struct	ModbusInfo

Public Member Functions
	Modbus (BaseLib::SharedObjects *baseLib, ModbusInfo &serverInfo)

virtual	~Modbus ()
	Destructor. More...

void	setSlaveId (uint8_t value)
	Sets the slave ID. More...

void	setDebug (bool value)
	Enables or disables debug mode (disabled by default). More...

void	connect ()
	Opens the connection to the Modbus server. More...

void	disconnect ()
	Closes the connection to the Modbus server. More...

bool	isConnected ()
	Checks if the socket is connected. More...

void	readCoils (uint16_t startingAddress, std::vector< uint8_t > &buffer, uint16_t coilCount)
	Executes modbus function 01 (0x01) "Read Coils". More...

void	readDiscreteInputs (uint16_t startingAddress, std::vector< uint8_t > &buffer, uint16_t inputCount)
	Executes modbus function 02 (0x02) "Read Discrete Inputs". More...

void	readHoldingRegisters (uint16_t startingAddress, std::vector< uint16_t > &buffer, uint16_t registerCount)
	Executes modbus function 03 (0x03) "Read Holding Registers". More...

void	readInputRegisters (uint16_t startingAddress, std::vector< uint16_t > &buffer, uint16_t registerCount)
	Executes modbus function 04 (0x04) "Read Input Registers". More...

void	writeSingleCoil (uint16_t address, bool value)
	Executes modbus function 05 (0x05) "Write Single Coil". More...

void	writeSingleRegister (uint16_t address, uint16_t value)
	Executes modbus function 06 (0x06) "Write Single Register". More...

void	writeMultipleCoils (uint16_t startAddress, const std::vector< uint8_t > &values, uint16_t coilCount)
	Executes modbus function 15 (0x0F) "Write Multiple Coils". More...

void	writeMultipleRegisters (uint16_t startAddress, const std::vector< uint16_t > &values, uint16_t registerCount)
	Executes modbus function 16 (0x10) "Write Multiple Registers". More...

void	readWriteMultipleRegisters (uint16_t readStartAddress, std::vector< uint16_t > &readBuffer, uint16_t readRegisterCount, uint16_t writeStartAddress, const std::vector< uint16_t > &writeValues, uint16_t writeRegisterCount)
	Executes modbus function 23 (0x17) "Read/Write Multiple Registers". More...

DeviceInfo	readDeviceIdentification ()
	Reads all device identification and returns it as a DeviceInfo struct. More...

Detailed Description

This class provides a Modbus client.

The class is thread safe.

Modbus Client Example Code

Save the example below in main.cpp and compile with:

g++ -o main -std=c++11 main.cpp -lhomegear-base -lgcrypt -lgnutls

Start with:

./main

Example code:

// This program connects to a Modbus server, sets a register to "0xFFFF" and 2 seconds later to "0x0000".
#include <homegear-base/BaseLib.h>

std::shared_ptr<BaseLib::SharedObjects> _bl;

int main()
{
    _bl.reset(new BaseLib::SharedObjects(false));

    BaseLib::Modbus::ModbusInfo modbusInfo;
    modbusInfo.hostname = "192.168.0.206"; //Replace with the IP address or hostname of your Modbus server.

    BaseLib::Modbus modbus(_bl.get(), modbusInfo);

    try
    {
        modbus.connect();
        modbus.writeSingleRegister(0x2001, 0xFFFF); //Replace with a working register address and value
        std::this_thread::sleep_for(std::chrono::milliseconds(2000));
        modbus.writeSingleRegister(0x2001, 0x0000);  //Replace with a working register address and value
        modbus.disconnect();
    }
    catch(BaseLib::ModbusException& ex)
    {
        std::cerr << "Code: " << (int32_t)ex.getCode()
                  << ", response packet: " << BaseLib::HelperFunctions::getHexString(ex.getPacket())
                  << ", message: " << ex.what() << std::endl;
    }
    catch(BaseLib::Exception& ex)
    {
        std::cerr << ex.what() << std::endl;
    }
}

Constructor & Destructor Documentation

§ Modbus()

BaseLib::Modbus::Modbus	(	BaseLib::SharedObjects *	baseLib,
		Modbus::ModbusInfo &	serverInfo
	)

§ ~Modbus()

BaseLib::Modbus::~Modbus ( )

virtual

Destructor.

Member Function Documentation

§ connect()

void BaseLib::Modbus::connect ( )

Opens the connection to the Modbus server.

Exceptions

SocketOperationException When the connection cannot be established.

§ disconnect()

void BaseLib::Modbus::disconnect ( )

Closes the connection to the Modbus server.

§ isConnected()

bool BaseLib::Modbus::isConnected ( )

inline

Checks if the socket is connected.

Returns: Returns true when the socket is connected and false otherwise.

§ readCoils()

void BaseLib::Modbus::readCoils	(	uint16_t	startingAddress,
		std::vector< uint8_t > &	buffer,
		uint16_t	coilCount
	)

Executes modbus function 01 (0x01) "Read Coils".

Parameters

	startingAddress	Valid values range from 0x0000 to 0xFFFF.
[out]	buffer	The buffer to fill. Make sure the size is at least number of coils bits.
	coilCount	The number of coils to read (from 1 to 2000 [= 0x7D0]).

Returns: Returns the coil states as a byte array. The least significant bit is to the left (in contrast to the Modbus packet). So the bits and bytes can be read from left to right.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ readDeviceIdentification()

Modbus::DeviceInfo BaseLib::Modbus::readDeviceIdentification ( )

Reads all device identification and returns it as a DeviceInfo struct.

Returns: A DeviceInfo struct containing all identification objects (basic, regular and extended).

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusServerBusyException	Thrown when the server is currently busy.

§ readDiscreteInputs()

void BaseLib::Modbus::readDiscreteInputs	(	uint16_t	startingAddress,
		std::vector< uint8_t > &	buffer,
		uint16_t	inputCount
	)

Executes modbus function 02 (0x02) "Read Discrete Inputs".

Parameters

	startingAddress	Valid values range from 0x0000 to 0xFFFF.
[out]	buffer	The buffer to fill. Make sure the size is at least number of inputs bits.
	inputCount	The number of inputs to read (from 1 to 2000 [= 0x7D0]).

Returns: Returns the input states as a byte array. The least significant bit is to the left (in contrast to the Modbus packet). So the bits and bytes can be read from left to right.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ readHoldingRegisters()

void BaseLib::Modbus::readHoldingRegisters	(	uint16_t	startingAddress,
		std::vector< uint16_t > &	buffer,
		uint16_t	registerCount
	)

Executes modbus function 03 (0x03) "Read Holding Registers".

Parameters

	startingAddress	Valid values range from 0x0000 to 0xFFFF.
[out]	buffer	The buffer to fill. Make sure the size is at least number of number of registers.
	registerCount	The number of registers to read (from 1 to 125 [= 0x7D]).

Returns: Returns the register values.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ readInputRegisters()

void BaseLib::Modbus::readInputRegisters	(	uint16_t	startingAddress,
		std::vector< uint16_t > &	buffer,
		uint16_t	registerCount
	)

Executes modbus function 04 (0x04) "Read Input Registers".

Parameters

	startingAddress	Valid values range from 0x0000 to 0xFFFF.
[out]	buffer	The buffer to fill. Make sure the size is at least number of number of registers.
	registerCount	The number of registers to read (from 1 to 125 [= 0x7D]).

Returns: Returns the register values.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ readWriteMultipleRegisters()

void BaseLib::Modbus::readWriteMultipleRegisters	(	uint16_t	readStartAddress,
		std::vector< uint16_t > &	readBuffer,
		uint16_t	readRegisterCount,
		uint16_t	writeStartAddress,
		const std::vector< uint16_t > &	writeValues,
		uint16_t	writeRegisterCount
	)

Executes modbus function 23 (0x17) "Read/Write Multiple Registers".

Parameters

	readStartAddress	Valid values range from 0x0000 to 0xFFFF.
[out]	readBuffer	The buffer to read values to.
	readRegisterCount	The number of registers to read from 0x0001 to 0x007D.
	writeStartAddress	Valid values range from 0x0000 to 0xFFFF.
	writeValues	The values to write.
	writeRegisterCount	The number of registers to write from 0x0001 to 0x0079.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ setDebug()

void BaseLib::Modbus::setDebug ( bool value )

inline

Enables or disables debug mode (disabled by default).

In debug mode all packets are written to the standard output.

§ setSlaveId()

void BaseLib::Modbus::setSlaveId ( uint8_t value )

inline

Sets the slave ID.

For Modbus over TCP this is normally unnecessary. It is needed to reach devices on a serial network or for devices with broken firmware. The default value is "0xFF". Disconnecting doesn't change the ID. It can be set before "connect()" is executed.

§ writeMultipleCoils()

void BaseLib::Modbus::writeMultipleCoils	(	uint16_t	startAddress,
		const std::vector< uint8_t > &	values,
		uint16_t	coilCount
	)

Executes modbus function 15 (0x0F) "Write Multiple Coils".

Parameters

startAddress	Valid values range from 0x0000 to 0xFFFF.
values	The values to write. The least significant bit is to the left (in contrast to the Modbus packet). So the bits and bytes can be read from left to right.
coilCount	The number of coils to write from 0x0001 to 0x07B0.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ writeMultipleRegisters()

void BaseLib::Modbus::writeMultipleRegisters	(	uint16_t	startAddress,
		const std::vector< uint16_t > &	values,
		uint16_t	registerCount
	)

Executes modbus function 16 (0x10) "Write Multiple Registers".

Parameters

startAddress	Valid values range from 0x0000 to 0xFFFF.
values	The values to write.
registerCount	The number of registers to write from 0x0001 to 0x007B.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ writeSingleCoil()

void BaseLib::Modbus::writeSingleCoil	(	uint16_t	address,
		bool	value
	)

Executes modbus function 05 (0x05) "Write Single Coil".

Parameters

address	Valid values range from 0x0000 to 0xFFFF.
value	The value to set the coil to.

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

§ writeSingleRegister()

void BaseLib::Modbus::writeSingleRegister	(	uint16_t	address,
		uint16_t	value
	)

Executes modbus function 06 (0x06) "Write Single Register".

Parameters

address	Valid values range from 0x0000 to 0xFFFF.
value	The value to set the register to (between 0x0000 and 0xFFFF).

Exceptions

SocketOperationException	On socket errors.
SocketTimeOutException	On socket timeout.
SocketClosedException	When the socket is closed during the request.
ModbusException	Thrown on all Modbus errors.
ModbusServerBusyException	Thrown when the server is currently busy.

The documentation for this class was generated from the following files:

Sockets/Modbus.h
Sockets/Modbus.cpp

Classes

Public Member Functions

Detailed Description

Modbus Client Example Code

Constructor & Destructor Documentation

§ Modbus()

§ ~Modbus()

Member Function Documentation

§ connect()

§ disconnect()

§ isConnected()

§ readCoils()

§ readDeviceIdentification()

§ readDiscreteInputs()

§ readHoldingRegisters()

§ readInputRegisters()

§ readWriteMultipleRegisters()

§ setDebug()

§ setSlaveId()

§ writeMultipleCoils()

§ writeMultipleRegisters()

§ writeSingleCoil()

§ writeSingleRegister()