modbus_tcp_master.h File Reference

Modbus/TCP master function definitions. More...

#include <stdbool.h>
#include <stdint.h>
#include <modbus_core/modbus.h>
#include <modbus_core/modbus_exceptions.h>
#include <modbus_core/modbus_types.h>
#include <modbus_core/modbus_rtos.h>
#include <modbus_tcp/modbus_tcp.h>

Data Structures
struct	mb_tcp_master_ch_t
	Structure representing a Modbus/TCP master channel. More...

Macros
#define	MB_TRANS_EVENT_COMPLETED   0
	Modbus/TCP transaction successfully completed event.
#define	MB_TRANS_EVENT_TIMEOUT   1
	Modbus/TCP transaction timeout event.

Typedefs
typedef void(*	transaction_callback) (uint16_t trans_id, int event)
	Transaction callback.

Functions
mb_tcp_master_ch_t *	mb_tcp_master_open (const ip_addr_t *slave_addr, uint16_t slave_port, uint8_t trans_count, transaction_callback trans_callback)
	Opens a master channel.
int	mb_tcp_master_connect (mb_tcp_master_ch_t *ch, uint32_t timeout)
	Opens the connection to the slave.
int	mb_tcp_master_disconnect (mb_tcp_master_ch_t *ch, uint32_t timeout)
	Closes the connection to the slave.
int	mb_tcp_master_close (mb_tcp_master_ch_t *ch)
	Closes a Modbus/TCP master channel.
int	mb_tcp_master_loop (mb_tcp_master_ch_t *ch)
	Processes pending transactions.
int	mb_tcp_rd_coils (mb_tcp_master_ch_t *ch, uint8_t *buf, uint8_t unit_id, uint16_t addr, uint16_t qty, uint16_t timeout)
	Makes a read coils request on the provided channel.
int	mb_tcp_rd_discrete_inputs (mb_tcp_master_ch_t *ch, uint8_t *buf, uint8_t unit_id, uint16_t addr, uint16_t qty, uint16_t timeout)
	Makes a read discrete inputs request on the provided channel.
int	mb_tcp_rd_holding_regs (mb_tcp_master_ch_t *ch, uint16_t *buf, uint8_t unit_id, uint16_t addr, uint16_t qty, uint16_t timeout)
	Makes a read holding registers request on the provided channel.
int	mb_tcp_rd_input_regs (mb_tcp_master_ch_t *ch, uint16_t *buf, uint8_t unit_id, uint16_t addr, uint16_t qty, uint16_t timeout)
	Makes a read input registers request on the provided channel.
int	mb_tcp_wr_single_coil (mb_tcp_master_ch_t *ch, bool value, uint8_t unit_id, uint16_t addr, uint16_t timeout)
	Makes a write single coil request on the provided channel.
int	mb_tcp_wr_single_reg (mb_tcp_master_ch_t *ch, uint16_t value, uint8_t unit_id, uint16_t addr, uint16_t timeout)
	Makes a write single register request on the provided channel.
int	mb_tcp_wr_coils (mb_tcp_master_ch_t *ch, uint8_t *values, uint8_t unit_id, uint16_t addr, uint16_t qty, uint16_t timeout)
	Makes a write multiple coils request on the provided channel.
int	mb_tcp_wr_regs (mb_tcp_master_ch_t *ch, uint16_t *values, uint8_t unit_id, uint16_t addr, uint16_t qty, uint16_t timeout)
	Makes a write multiple coils request on the provided channel.

Detailed Description

Modbus/TCP master function definitions.

Author

Tecnologix, 2021

Typedef Documentation

transaction_callback

typedef void(* transaction_callback) (uint16_t trans_id, int event)

Transaction callback.

Parameters

trans_id	transaction id.
event	transaction event. It can be MB_TRANS_EVENT_COMPLETED or MB_TRANS_EVENT_TIMEOUT.

Function Documentation

mb_tcp_master_close()

int mb_tcp_master_close

(

mb_tcp_master_ch_t *

ch

)

Closes a Modbus/TCP master channel.

The connection must be closed before calling this function.

Parameters

ch	opened master channel to be closed.

Returns

0 if the channel was successfully closed, a negative number otherwise.

mb_tcp_master_connect()

int mb_tcp_master_connect	(	mb_tcp_master_ch_t *	ch,
		uint32_t	timeout )

Opens the connection to the slave.

Parameters

ch	opened master channel.
timeout	timeout for the connection to be established.

Returns

0 if the connection was successfully opened, a negative number otherwise.

mb_tcp_master_disconnect()

int mb_tcp_master_disconnect	(	mb_tcp_master_ch_t *	ch,
		uint32_t	timeout )

Closes the connection to the slave.

Parameters

ch	opened master channel.
timeout	timeout for the connection to be closed.

Returns

0 if the connection was successfully closed, a negative number otherwise.

mb_tcp_master_loop()

int mb_tcp_master_loop

(

mb_tcp_master_ch_t *

ch

)

Processes pending transactions.

This function is supposed to be called in a loop and processes responses and timeouts calling the callback function provided when the master channel was opened.

Parameters

ch	opened master channel.

Returns

number of transactions that were processed (completed or timed out).

mb_tcp_master_open()

mb_tcp_master_ch_t * mb_tcp_master_open	(	const ip_addr_t *	slave_addr,
		uint16_t	slave_port,
		uint8_t	trans_count,
		transaction_callback	trans_callback )

Opens a master channel.

Parameters

slave_addr	IP address of the slave.
slave_port	slave TCP port to connect to.
trans_count	maximum number of concurrent transactions.
trans_callback	function to be invoked when a transaction ends or its timeout expires.

Returns

the opened channel or NULL if something went wrong.

mb_tcp_rd_coils()

int mb_tcp_rd_coils	(	mb_tcp_master_ch_t *	ch,
		uint8_t *	buf,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	qty,
		uint16_t	timeout )

Makes a read coils request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
buf	buffer to store the data read. It must be large enough to store the response.
unit_id	unit id of the slave.
addr	coils starting address.
qty	number of coils to be read.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.

mb_tcp_rd_discrete_inputs()

int mb_tcp_rd_discrete_inputs	(	mb_tcp_master_ch_t *	ch,
		uint8_t *	buf,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	qty,
		uint16_t	timeout )

Makes a read discrete inputs request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
buf	buffer to store the data read. It must be large enough to store the response.
unit_id	unit id of the slave.
addr	discrete inputs starting address.
qty	number of discrete inputs to be read.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.

mb_tcp_rd_holding_regs()

int mb_tcp_rd_holding_regs	(	mb_tcp_master_ch_t *	ch,
		uint16_t *	buf,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	qty,
		uint16_t	timeout )

Makes a read holding registers request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
buf	buffer to store the data read. It must be large enough to store the response.
unit_id	unit id of the slave.
addr	holding regiters starting address.
qty	number of holding registers to be read.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.

mb_tcp_rd_input_regs()

int mb_tcp_rd_input_regs	(	mb_tcp_master_ch_t *	ch,
		uint16_t *	buf,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	qty,
		uint16_t	timeout )

Makes a read input registers request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
buf	buffer to store the data read. It must be large enough to store the response.
unit_id	unit id of the slave.
addr	input registers starting address.
qty	number of input registers to be read.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.

mb_tcp_wr_coils()

int mb_tcp_wr_coils	(	mb_tcp_master_ch_t *	ch,
		uint8_t *	values,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	qty,
		uint16_t	timeout )

Makes a write multiple coils request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
values	value to be written.
unit_id	unit id of the slave.
addr	starting address of the coils to be written.
qty	number of coils to be written.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.

mb_tcp_wr_regs()

int mb_tcp_wr_regs	(	mb_tcp_master_ch_t *	ch,
		uint16_t *	values,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	qty,
		uint16_t	timeout )

Makes a write multiple coils request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
values	value to be written.
unit_id	unit id of the slave.
addr	starting address of the registers to be written.
qty	number of registers to be written.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.

mb_tcp_wr_single_coil()

int mb_tcp_wr_single_coil	(	mb_tcp_master_ch_t *	ch,
		bool	value,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	timeout )

Makes a write single coil request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
value	value to be written.
unit_id	unit id of the slave.
addr	address of the coil to be written.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.

mb_tcp_wr_single_reg()

int mb_tcp_wr_single_reg	(	mb_tcp_master_ch_t *	ch,
		uint16_t	value,
		uint8_t	unit_id,
		uint16_t	addr,
		uint16_t	timeout )

Makes a write single register request on the provided channel.

The transaction response is processed by the mb_tcp_master_loop function.

Parameters

ch	opened master channel.
value	value to be written.
unit_id	unit id of the slave.
addr	address of the register to be written.
timeout	transaction timeout.

Returns

the 16-bit transaction id or a negative number if an error occurs.