MbusAsciiSlaveProtocol Class Reference
[Serial Protocols]

Inheritance diagram for MbusAsciiSlaveProtocol:

Collaboration diagram for MbusAsciiSlaveProtocol:

Detailed Description

Modbus ASCII Slave Protocol class.

This class realises the Modbus ASCII slave protocol. It provides functions to start-up and to execute the server engine which includes opening and closing of the serial port. Upon receipt of a valid master query the server engine calls Data Provider methods to exchange data with the user application. For a more detailed description which Modbus data and control functions have been implemented in the server engine see section Server Functions common to all Protocol Flavours.

It is possible to instantiate multiple instances for establishing multiple connections on different serial ports (They should be executed in separate threads).

Version:: 1.0

See also:: Server Functions common to all Protocol Flavours, MbusSlaveServer

Serial Server Management Functions

virtual int startupServer (const char *const portName, long baudRate, int dataBits, int stopBits, int parity)

Puts the Modbus server into operation.

int startupServer (const char *const portName, long baudRate)

Puts the Modbus RTU server into operation and opens the associated serial port with default port parameters.

virtual int startupServer (int slaveAddr, const char *const portName, long baudRate, int dataBits, int stopBits, int parity)

Puts the Modbus server into operation using a single slave address and data table.

int startupServer (int slaveAddr, const char *const portName, long baudRate)

Puts the Modbus RTU server into operation and opens the associated serial port with default port parameters.

void shutdownServer ()

Shuts down the Modbus server.

int isStarted ()

Returns if server has been started up.

virtual int enableRs485Mode (int rtsDelay)

Enables RS485 mode.

Server Management Functions

int addDataTable (int slaveAddr, MbusDataTableInterface *dataTablePtr)

Associates a protocol object with a Data Provider and a slave address.

Protocol Configuration

long setTimeout (long timeOut)

Configures master transmit time-out supervision.

long getTimeout ()

Returns the master time-out supervision value.

Transmission Statistic Functions

unsigned long getTotalCounter ()

Returns how often a message transfer has been executed.

void resetTotalCounter ()

Resets total message transfer counter.

unsigned long getSuccessCounter ()

Returns how often a message transfer was successful.

void resetSuccessCounter ()

Resets successful message transfer counter.

Utility Functions

static char * getPackageVersion ()

Returns the package version number.

Public Types

enum { SER_DATABITS_7 = SerialPort::SER_DATABITS_7, SER_DATABITS_8 = SerialPort::SER_DATABITS_8 }

enum { SER_STOPBITS_1 = SerialPort::SER_STOPBITS_1, SER_STOPBITS_2 = SerialPort::SER_STOPBITS_2 }

enum { SER_PARITY_NONE = SerialPort::SER_PARITY_NONE, SER_PARITY_EVEN = SerialPort::SER_PARITY_EVEN, SER_PARITY_ODD = SerialPort::SER_PARITY_ODD }

Public Member Functions

MbusAsciiSlaveProtocol ()

Constructs a MbusAsciiSlaveProtocol object.

MbusAsciiSlaveProtocol (MbusDataTableInterface *dataTablePtr)

Constructs a MbusAsciiSlaveProtocol object and associates it with a Data Provider.

int serverLoop ()

Modbus ASCII slave server loop.

Protected Types

enum { SER_RS232, SER_RS485 }

Member Enumeration Documentation

anonymous enum [inherited]

Enumeration values:

SER_DATABITS_7 7 data bits

SER_DATABITS_8 8 data bits

anonymous enum [inherited]

Enumeration values:

SER_STOPBITS_1 1 stop bit

SER_STOPBITS_2 2 stop bits

anonymous enum [inherited]

Enumeration values:

SER_PARITY_NONE No parity.

SER_PARITY_EVEN Even parity.

SER_PARITY_ODD Odd parity.

anonymous enum [protected, inherited]

Enumeration values:

SER_RS232 RS232 mode w/o RTS/CTS handshake.

SER_RS485 RS485 mode: RTS enables/disables transmitter.

Constructor & Destructor Documentation

MbusAsciiSlaveProtocol ( )

Constructs a MbusAsciiSlaveProtocol object.
The association with a Data Provider is done after construction using the addDataTable method.

Parameters:

dataTablePtr Modbus data table pointer. Must point to a Data Provider object derived from the MbusDataTableInterface class. The Data Provider is the interface between your application data and the Modbus network.

MbusAsciiSlaveProtocol ( MbusDataTableInterface * dataTablePtr )

Constructs a MbusAsciiSlaveProtocol object and associates it with a Data Provider.
Function is kept for compatibility with previous API versions, do not use for new implementations.

Parameters:

dataTablePtr Modbus data table pointer. Must point to a Data Provider object derived from the MbusDataTableInterface class. The Data Provider is the interface between your application data and the Modbus network.

Deprecated:
This function is deprecated. The preferred way of assigning a dataTable is using the default constructor and configuring data table and slave address using addDataTable method.

Member Function Documentation

int serverLoop ( ) [virtual]

Modbus ASCII slave server loop.
This server loop must be called continuously. It must not be blocked. The server has to be started before calling the serverLoop() method.

Returns:
FTALK_SUCCESS on success or error code. See Protocol Errors and Exceptions for a list of error codes.

Implements MbusSlaveServer.

int startupServer ( const char *const portName,

long baudRate,

int dataBits,

int stopBits,

int parity

) [virtual, inherited]

Puts the Modbus server into operation.
This function opens the serial port. After the port has been opened queries from a Modbus master will be processed.

Parameters:

portName Serial port identifier (e.g. "COM1", "/dev/ser1 or /dev/ttyS0")

baudRate The port baudRate in bps (typically 1200 - 9600).

dataBits Must be SER_DATABITS_8 for RTU

stopBits SER_STOPBITS_1: 1 stop bit, SER_STOPBITS_2: 2 stop bits

parity SER_PARITY_NONE: no parity, SER_PARITY_ODD: odd parity, SER_PARITY_EVEN: even parity

Returns:
FTALK_SUCCESS on success or error code. See Protocol Errors and Exceptions for a list of error codes.

Reimplemented in MbusRtuSlaveProtocol.

int startupServer ( const char *const portName,

long baudRate

) [inherited]

Puts the Modbus RTU server into operation and opens the associated serial port with default port parameters.
This function opens the serial port with 8 databits, 1 stopbit and no parity and initialises the server engine.

Parameters:

portName Serial port identifier (e.g. "COM1", "/dev/ser1" or "/dev/ttyS0")

baudRate The port baudRate in bps (typically 1200 - 9600).

Returns:
FTALK_SUCCESS on success or error code. See Protocol Errors and Exceptions for a list of error codes.

int startupServer ( int slaveAddr,

const char *const portName,

long baudRate,

int dataBits,

int stopBits,

int parity

) [virtual, inherited]

Puts the Modbus server into operation using a single slave address and data table.
This function opens the serial port. After the port has been opened queries from a Modbus master will be processed.
Function is kept for compatibility with previous API versions, do not use for new implementations.

Parameters:

slaveAddr Modbus slave address for server to listen on (1-255)

portName Serial port identifier (e.g. "COM1", "/dev/ser1 or /dev/ttyS0")

baudRate The port baudRate in bps (typically 1200 - 9600).

dataBits Must be SER_DATABITS_8 for RTU

stopBits SER_STOPBITS_1: 1 stop bit, SER_STOPBITS_2: 2 stop bits

parity SER_PARITY_NONE: no parity, SER_PARITY_ODD: odd parity, SER_PARITY_EVEN: even parity

Returns:
FTALK_SUCCESS on success or error code. See Protocol Errors and Exceptions for a list of error codes.

Deprecated:
This function is deprecated. The preferred way of assigning a slave address is using the default constructor and configuring data table and slave address using addDataTable method.

Reimplemented in MbusRtuSlaveProtocol.

int startupServer ( int slaveAddr,

const char *const portName,

long baudRate

) [inherited]

Puts the Modbus RTU server into operation and opens the associated serial port with default port parameters.
This function opens the serial port with 8 databits, 1 stopbit and no parity and initialises the server engine.
Function is kept for compatibility with previous API versions, do not use for new implementations.

Parameters:

slaveAddr Modbus slave address for server to listen on (1-255)

portName Serial port identifier (e.g. "COM1", "/dev/ser1" or "/dev/ttyS0")

baudRate The port baudRate in bps (typically 1200 - 9600).

Returns:
FTALK_SUCCESS on success or error code. See Protocol Errors and Exceptions for a list of error codes.

Deprecated:
This function is deprecated. The preferred way of assigning a slave address is using the default constructor and configuring data table and slave address using addDataTable method.

void shutdownServer ( ) [virtual, inherited]

Shuts down the Modbus server.
This function also closes the serial port.
Reimplemented from MbusSlaveServer.

int isStarted ( ) [virtual, inherited]

Returns if server has been started up.

Return values:

true = started

false = shutdown

Implements MbusSlaveServer.

int enableRs485Mode ( int rtsDelay ) [virtual, inherited]

Enables RS485 mode.
In RS485 mode the RTS signal can be used to enable and disable the transmitter of a RS232/RS485 converter. The RTS signal is asserted before sending data. It is cleared after the transmit buffer has been emptied and in addition the specified delay time has elapsed. The delay time is necessary because even the transmit buffer is already empty, the UART's FIFO will still contain unsent characters.

Warning:
The use of RTS controlled RS232/RS485 converters should be avoided if possible. It is difficult to determine the exact time when to switch off the transmitter with non real-time operating systems like Windows and Linux. If it is switched off to early characters might still sit in the FIFO or the transmit register of the UART and these characters will be lost. Hence the slave will not recognize the message. On the other hand if it is switched off too late then the slave's message is corrupted and the master will not recognize the message.

Remarks:
The delay value is indicative only and not guaranteed to be maintained. How precise it is followed depends on the operating system used, it's scheduling priority and it's system timer resolution.

Note:
A protocol must be closed in order to configure it.

Parameters:

rtsDelay Delay time in ms (Range: 0 - 100000) which applies after the transmit buffer is empty. 0 disables this mode.

Return values:

FTALK_SUCCESS Success

FTALK_ILLEGAL_ARGUMENT_ERROR Argument out of range

FTALK_ILLEGAL_STATE_ERROR Protocol is already open

MbusAsciiSlaveProtocol Class Reference [Serial Protocols]

Detailed Description

Serial Server Management Functions

Server Management Functions

Protocol Configuration

Transmission Statistic Functions

Utility Functions

Public Types

Public Member Functions

Protected Types

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

MbusAsciiSlaveProtocol Class Reference
[Serial Protocols]