modbus.h File Reference

Modbus interface to the application. More...

#include <stdint.h>
#include <modbus_core/modbus_types.h>

Data Structures
struct	mb_pdu_t
	Represents a modbus Protocol Data Unit (PDU). More...
struct	mb_data_handlers_t
	This structure contains pointers to data handlers. More...
struct	mb_info_t
	Contains information for message processing. More...

Macros
#define	MODBUS_MAX_PDU_DATA_SIZE   (252)
	Maximum size of data field in a modbus PDU including checksum.
#define	ADR_BROADCAST   (0x00)
	Broadcast address for modbus messages.
#define	MSG_RECEIVED   (2)
	Modbus message received.
#define	MSG_TIMEOUT   (3)
	Modbus message not received within timeout.
#define	MB_JBUS   (1)
	Jbus mode.
#define	MB_MODBUS   (0)
	Modbus mode.
#define	MB_FC_READ_COILS   (0x01)
	Modbus function code for reading coils.
#define	MB_FC_READ_DISCRETE_INPUTS   (0x02)
	Modbus function code for reading discrete inputs.
#define	MB_FC_READ_HOLD_REGISTERS   (0x03)
	Modbus function code for reading holding registers.
#define	MB_FC_READ_INPUT_REGISTERS   (0x04)
	Modbus function code for reading input registers.
#define	MB_FC_WRITE_SINGLE_COIL   (0x05)
	Modbus function code for writing a single coil.
#define	MB_FC_WRITE_SINGLE_REGISTER   (0x06)
	Modbus function code for writing a single register.
#define	MB_FC_WRITE_MULTI_COILS   (0x0F)
	Modbus function code for writing multiple coils.
#define	MB_FC_WRITE_MULTI_REGISTERS   (0x10)
	Modbus function code for writing multiple registers.
#define	MB_RC_OK   (0)
	No errors.
#define	MB_RC_NO_RESPONSE   (-1)
	No response within timeout.
#define	MB_RC_ERR_BYTE_COUNT   (-2)
	No response error in response length.

Functions
uint8_t	mb_is_func_supported (uint8_t function_code)
	Checks if the function identified by the given number is supported.
uint8_t	mb_process_pdu (mb_pdu_t *req_pdu, mb_pdu_t *resp_pdu, mb_info_t *info)
	Processes a modbus PDU and creates the corresponding response if it is necessary.
void	mb_queue_byte (uint8_t val, mb_pdu_t *pdu)
	Writes a byte in the message.
void	mb_queue_word (uint16_t val, mb_pdu_t *pdu)
	Writes a word in the message.

Detailed Description

Modbus interface to the application.

Author

Tecnologix, 2014

Function Documentation

mb_is_func_supported()

uint8_t mb_is_func_supported

(

uint8_t

function_code

)

Checks if the function identified by the given number is supported.

Parameters

function_code

number corresponding to the function to test the support for.

Returns

0 if the function corresponding to the given function code is unsupported.

mb_process_pdu()

uint8_t mb_process_pdu	(	mb_pdu_t *	req_pdu,
		mb_pdu_t *	resp_pdu,
		mb_info_t *	info )

Processes a modbus PDU and creates the corresponding response if it is necessary.

Parameters

[in]	req_pdu	modbus PDU to process.
[out]	resp_pdu	response PDU. It can be a response PDU or an exception PDU.
[in]	info	informations needed to process the message.

Returns

MB_NOERROR if everything was ok, an error code otherwise.

mb_queue_byte()

void mb_queue_byte	(	uint8_t	val,
		mb_pdu_t *	pdu )

Writes a byte in the message.

Parameters

val	byte to write.
pdu	pointer to the pdu.

mb_queue_word()

void mb_queue_word	(	uint16_t	val,
		mb_pdu_t *	pdu )

Writes a word in the message.

Parameters

val	byte to write.
pdu	pointer to the pdu.