modbus_rtu.h

linux下的modbus协议,很好用,欢迎大家下载,在国外网站上获得的

/* 		modbus_rtu.h

   By P.Costigan email: [e-mail] http://pcscada.com.au
 
   These library of functions are designed to enable a program send and
   receive data from a device that communicates using the Modbus protocol.
 
   Copyright (C) 2000 Philip Costigan  P.C. SCADA LINK PTY. LTD.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                    




   The functions included here have been derived from the
   Modicon Modbus Protocol Reference Guide
   which can be obtained from Schneider at www.schneiderautomation.com.
 
   This code has its origins with
   [e-mail] (http://www.pmcrae.freeserve.co.uk)
   who wrote a small program to read 100 registers from a modbus slave.
 
   I have used his code as a catalist to produce this more functional set
   of functions. Thanks paul.


 */


#ifndef MODBUS_RTU_H
#define MODBUS_RTU_H

#define MAX_DATA_LENGTH 246
#define MAX_QUERY_LENGTH 255
#define MAX_RESPONSE_LENGTH 1024

#define FALSE 0 
#define TRUE 1



/***********************************************************************

	 Note: All functions used for sending or receiving data via
	       modbus return these return values.


	Returns:	string_length if OK
			0 if failed
			Less than 0 for exception errors

***********************************************************************/

#define COMMS_FAILURE 0
#define ILLEGAL_FUNCTION -1
#define ILLEGAL_DATA_ADDRESS -2
#define ILLEGAL_DATA_VALUE -3
#define SLAVE_DEVICE_FAILURE -4
#define ACKNOWLEDGE -5
#define SLAVE_DEVICE_BUSY -6
#define NEGATIVE_ACKNOWLEDGE -7
#define MEMORY_PARITY_ERROR -8

#define PORT_FAILURE -11



/************************************************************************

	read_coil_status()

	reads the boolean status of coils and sets the array elements
	in the destination to TRUE or FALSE.

*************************************************************************/

int read_coil_status( int slave, int start_addr, int count,
			  int *dest, int dest_size, int fd );





/************************************************************************

	read_input_status()

	same as read_coil_status but reads the slaves input table.

************************************************************************/

int read_input_status( int slave, int start_addr, int count,
			   int *dest, int dest_size, int fd );





/***********************************************************************

	read_holding_registers()

	Read the holding registers in a slave and put the data into
	an array.

************************************************************************/

#define MAX_READ_REGS 100

int read_holding_registers( int slave, int start_addr, int count, 
			  	int *dest, int dest_size, int fd );




/***********************************************************************

	read_input_registers()

	Read the inputg registers in a slave and put the data into
	an array.

***********************************************************************/

#define MAX_INPUT_REGS 100

int read_input_registers( int slave, int start_addr, int count,
				int *dest, int dest_size, int fd );







/************************************************************************

	force_single_coil()

	turn on or off a single coil on the slave device.

************************************************************************/

int force_single_coil( int slave, int addr, int state, int fd );







/*************************************************************************

	preset_single_register()

	sets a value in one holding register in the slave device.

*************************************************************************/

int preset_single_register( int slave, int reg_addr, int value, int fd );






/*************************************************************************

	set_multiple_coils()

	Takes an array of ints and sets or resets the coils on a slave
	appropriatly.

**************************************************************************/

#define MAX_WRITE_COILS 800

int set_multiple_coils( int slave, int start_addr, 
			    int coil_count, int *data, int fd );






/*************************************************************************

	preset_multiple_registers()

	copy the values in an array to an array on the slave.

*************************************************************************/

#define MAX_WRITE_REGS 100

int preset_multiple_registers( int slave, int start_addr,
				   int reg_count, int *data, int fd );








/***************************************************************************

	set_up_comms

	This function sets up a serial port for RTU communications to
	modbus.


***************************************************************************/

int set_up_comms( char *device, int baud, char *parity );
/* baud should be the plain baud rate, eg 2400; zero for the default 9600.
 * If an unsupported baud rate is specified, prints a message to stderr and
 * uses 9600. */


#define TO_B110	3200000	/* These values are the timeout delays */
#define TO_B300 1600000	/* at the end of packets of data.      */
#define TO_B600  800000 /* At this stage a true calculation    */
#define TO_B1200 400000	/* has not been worked out. So these   */
#define TO_B2400 200000	/* values are just a guess.            */
#define TO_B4800 100000	/*                                     */
#define TO_B9600  50000	/* The spec says that a message frame  */
#define TO_B19200 25000	/* starts after a silent interval of   */
#define TO_B38400 12500 /* at least 3.5 character times.       */
#define TO_B57600  8333 /* These are uS times.                */
#define TO_B115200 4167 




#endif  /* MODBUS_RTU_H */