Arduino class library for communicating with Modbus devices over USB/RS232/485 (via RTU protocol). More...

#include <ModbusRtu.h>

Public Member Functions
void	begin ()

void	begin (long u32speed)
	Initialize class object.

void	begin (long u32speed, uint8_t u8config)
	Initialize class object.

void	begin (SoftwareSerial *sPort, long u32speed)
	Initialize class object.

void	clearError ()

void	end ()
	finish any communication and release serial communication port

uint16_t	getErrCnt ()
	error counter

uint8_t	getID ()
	get slave ID between 1 and 247

uint16_t	getInCnt ()
	number of incoming messages

uint8_t	getLastError ()
	get last error message

uint16_t	getOutCnt ()
	number of outcoming messages

uint8_t	getState ()

uint16_t	getTimeOut ()
	get communication watch-dog timer value

boolean	getTimeOutState ()
	get communication watch-dog timer state

bool	isLocked ()

	Modbus ()
	Default Constructor for Master through Serial.

	Modbus (uint8_t u8id)

	Modbus (uint8_t u8id, uint8_t u8serno)

	Modbus (uint8_t u8id, uint8_t u8serno, uint8_t u8txenpin)

int8_t	poll ()
	cyclic poll for master

int8_t	poll (uint16_t *regs, uint8_t u8size)
	cyclic poll for slave

int8_t	query (modbus_t telegram)
	only for master

void	setID (uint8_t u8id)
	write new ID for the slave

void	setTimeOut (uint16_t u16timeout)
	write communication watch-dog timer

Public Attributes
bool	debugSend

uint8_t	rxBuffer [MAX_BUFFER]

uint8_t	rxSize

Private Member Functions
void	buildException (uint8_t u8exception)
	This method builds an exception message.

uint16_t	calcCRC (uint8_t u8length)
	This method calculates CRC.

void	get_FC1 ()

void	get_FC3 ()

int8_t	getRxBuffer ()
	This method moves Serial buffer data to the Modbus au8Buffer.

void	init (uint8_t u8id)

void	init (uint8_t u8id, uint8_t u8serno, uint8_t u8txenpin)

int8_t	process_FC1 (uint16_t *regs, uint8_t u8size)
	This method processes functions 1 & 2 This method reads a bit array and transfers it to the master.

int8_t	process_FC15 (uint16_t *regs, uint8_t u8size)
	This method processes function 15 This method writes a bit array assigned by the master.

int8_t	process_FC16 (uint16_t *regs, uint8_t u8size)
	This method processes function 16 This method writes a word array assigned by the master.

int8_t	process_FC3 (uint16_t *regs, uint8_t u8size)
	This method processes functions 3 & 4 This method reads a word array and transfers it to the master.

int8_t	process_FC5 (uint16_t *regs, uint8_t u8size)
	This method processes function 5 This method writes a value assigned by the master to a single bit.

int8_t	process_FC6 (uint16_t *regs, uint8_t u8size)
	This method processes function 6 This method writes a value assigned by the master to a single word.

void	sendTxBuffer ()
	This method transmits au8Buffer to Serial line. Only if u8txenpin != 0, there is a flow handling in order to keep the RS485 transceiver in output state as long as the message is being sent. This is done with UCSRxA register. The CRC is appended to the buffer before starting to send it.

uint8_t	validateAnswer ()
	This method validates master incoming messages.

uint8_t	validateRequest ()
	This method validates slave incoming messages.

Private Attributes
uint16_t *	au16regs

uint8_t	au8Buffer [MAX_BUFFER]

modbus_t *	currentQuery

HardwareSerial *	port
	Pointer to Serial class object.

SoftwareSerial *	softPort
	Pointer to SoftwareSerial class object.

uint16_t	u16errCnt

uint16_t	u16InCnt

uint16_t	u16OutCnt

uint16_t	u16timeOut

uint32_t	u32time

uint32_t	u32timeOut

uint8_t	u8BufferSize

uint8_t	u8id
	0=master, 1..247=slave number

uint8_t	u8lastError

uint8_t	u8lastRec

uint8_t	u8regsize

uint8_t	u8serno
	serial port: 0-Serial, 1..3-Serial1..Serial3; 4: use software serial

uint8_t	u8state

uint8_t	u8txenpin
	flow control pin: 0=USB or RS-232 mode, >0=RS-485 mode

Detailed Description

Arduino class library for communicating with Modbus devices over USB/RS232/485 (via RTU protocol).

Definition at line 152 of file ModbusRtu.h.

Constructor & Destructor Documentation

◆ Modbus() [1/3]

Modbus::Modbus	(	uint8_t	u8id,
		uint8_t	u8serno )

Definition at line 245 of file ModbusRtu.h.

{
    init(u8id, u8serno, 0);
}

◆ Modbus() [2/3]

Modbus::Modbus	(	uint8_t	u8id,
		uint8_t	u8serno,
		uint8_t	u8txenpin )

Definition at line 263 of file ModbusRtu.h.

{
    init(u8id, u8serno, u8txenpin);
}

◆ Modbus() [3/3]

Modbus::Modbus ( uint8_t u8id )

Definition at line 282 of file ModbusRtu.h.

{
    init(u8id);
}

Member Function Documentation

◆ begin()

void Modbus::begin ( )

Definition at line 450 of file ModbusRtu.h.

{
    begin(19200);
}

◆ clearError()

void Modbus::clearError ( )

Definition at line 550 of file ModbusRtu.h.

{
    u16errCnt = 0;
}

◆ end()

void Modbus::end ( )

finish any communication and release serial communication port

◆ getTimeOut()

uint16_t Modbus::getTimeOut ( )

get communication watch-dog timer value

◆ init() [1/2]

void Modbus::init ( uint8_t u8id )

private

Definition at line 890 of file ModbusRtu.h.

{
    this->u8id = u8id;
    this->u8serno = 4;
    this->u8txenpin = 0;
    this->u16timeOut = 1000;
}

◆ init() [2/2]

void Modbus::init	(	uint8_t	u8id,
		uint8_t	u8serno,
		uint8_t	u8txenpin )

private

Definition at line 879 of file ModbusRtu.h.

{
    this->u8id = u8id;
    this->u8serno = (u8serno > 3) ? 0 : u8serno;
 
    // this->u8txenpin = u8txenpin;
    this->u8txenpin = 2; // Ignore input parameter u8txenpin and hardcode 2 for compatibility
 
    this->u16timeOut = 1000;
}

◆ isLocked()

bool Modbus::isLocked ( )

Definition at line 344 of file ModbusRtu.h.

{
    return currentQuery && (currentQuery->flags == QUERY_STATE::QUEUED || currentQuery->flags == QUERY_STATE::SENT);
}

Member Data Documentation

◆ au16regs

uint16_t* Modbus::au16regs

private

Definition at line 165 of file ModbusRtu.h.

◆ au8Buffer

uint8_t Modbus::au8Buffer[MAX_BUFFER]

private

Definition at line 162 of file ModbusRtu.h.

◆ currentQuery

modbus_t* Modbus::currentQuery

private

Definition at line 178 of file ModbusRtu.h.

◆ debugSend

bool Modbus::debugSend

Definition at line 214 of file ModbusRtu.h.

◆ port

HardwareSerial* Modbus::port

private

Pointer to Serial class object.

Definition at line 155 of file ModbusRtu.h.

◆ rxBuffer

uint8_t Modbus::rxBuffer[MAX_BUFFER]

Definition at line 217 of file ModbusRtu.h.

◆ rxSize

uint8_t Modbus::rxSize

Definition at line 216 of file ModbusRtu.h.

◆ softPort

SoftwareSerial* Modbus::softPort

private

Pointer to SoftwareSerial class object.

Definition at line 156 of file ModbusRtu.h.

◆ u16errCnt

uint16_t Modbus::u16errCnt

private

Definition at line 166 of file ModbusRtu.h.

◆ u16InCnt

uint16_t Modbus::u16InCnt

private

Definition at line 166 of file ModbusRtu.h.

◆ u16OutCnt

uint16_t Modbus::u16OutCnt

private

Definition at line 166 of file ModbusRtu.h.

◆ u16timeOut

uint16_t Modbus::u16timeOut

private

Definition at line 167 of file ModbusRtu.h.

◆ u32time

uint32_t Modbus::u32time

private

Definition at line 168 of file ModbusRtu.h.

◆ u32timeOut

uint32_t Modbus::u32timeOut

private

Definition at line 168 of file ModbusRtu.h.

◆ u8BufferSize

uint8_t Modbus::u8BufferSize

private

Definition at line 163 of file ModbusRtu.h.

◆ u8id

uint8_t Modbus::u8id

private

0=master, 1..247=slave number

Definition at line 157 of file ModbusRtu.h.

◆ u8lastError

uint8_t Modbus::u8lastError

private

Definition at line 161 of file ModbusRtu.h.

◆ u8lastRec

uint8_t Modbus::u8lastRec

private

Definition at line 164 of file ModbusRtu.h.

◆ u8regsize

uint8_t Modbus::u8regsize

private

Definition at line 169 of file ModbusRtu.h.

◆ u8serno

uint8_t Modbus::u8serno

private

serial port: 0-Serial, 1..3-Serial1..Serial3; 4: use software serial

Definition at line 158 of file ModbusRtu.h.

◆ u8state

uint8_t Modbus::u8state

private

Definition at line 160 of file ModbusRtu.h.

◆ u8txenpin

uint8_t Modbus::u8txenpin

private

flow control pin: 0=USB or RS-232 mode, >0=RS-485 mode

Definition at line 159 of file ModbusRtu.h.

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

ModbusRtu.h

Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Modbus() [1/3]

◆ Modbus() [2/3]

◆ Modbus() [3/3]

Member Function Documentation

◆ begin()

◆ clearError()

◆ end()

◆ getTimeOut()

◆ init() [1/2]

◆ init() [2/2]

◆ isLocked()

Member Data Documentation

◆ au16regs

◆ au8Buffer

◆ currentQuery

◆ debugSend

◆ port

◆ rxBuffer

◆ rxSize

◆ softPort

◆ u16errCnt

◆ u16InCnt

◆ u16OutCnt

◆ u16timeOut

◆ u32time

◆ u32timeOut

◆ u8BufferSize

◆ u8id

◆ u8lastError

◆ u8lastRec

◆ u8regsize

◆ u8serno

◆ u8state

◆ u8txenpin