libmodbus/modbus/modbus.h

/* 
   Copyright (C) 2001-2008 Stéphane Raimbault <stephane.raimbault@gmail.com>
  
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
  
   This library 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
   Lesser General Public License for more details.
  
   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the
   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.
*/

#ifndef _MODBUS_H_
#define _MODBUS_H_

#include <termios.h>
#include <arpa/inet.h>

#define MODBUS_TCP_DEFAULT_PORT 502

#define HEADER_LENGTH_RTU         0
#define PRESET_QUERY_SIZE_RTU     6
#define PRESET_RESPONSE_SIZE_RTU  2

#define HEADER_LENGTH_TCP         6
#define PRESET_QUERY_SIZE_TCP    12
#define PRESET_RESPONSE_SIZE_TCP  8

#define CHECKSUM_SIZE_RTU      2
#define CHECKSUM_SIZE_TCP      0        

/* 8 + HEADER_LENGTH_TCP */
#define MIN_QUERY_SIZE        14

/* MIN_RESPONSE_LENGTH + MAX(MAX*) */
#define MAX_PACKET_SIZE      261

#define MAX_READ_STATUS      800
#define MAX_READ_HOLD_REGS   100
#define MAX_READ_INPUT_REGS  100
#define MAX_WRITE_COILS      800
#define MAX_WRITE_REGS       100

#define REPORT_SLAVE_ID_SIZE 75

/* Time out between trames in microsecond */
#define TIME_OUT_BEGIN_OF_TRAME 500000
#define TIME_OUT_END_OF_TRAME   500000

#ifndef FALSE
#define FALSE 0
#endif

#ifndef TRUE
#define TRUE 1
#endif

#ifndef OFF
#define OFF 0
#endif

#ifndef ON
#define ON 1
#endif

/* Function codes */
#define FC_READ_COIL_STATUS          0x01  /* discretes inputs */
#define FC_READ_INPUT_STATUS         0x02  /* discretes outputs */
#define FC_READ_HOLDING_REGISTERS    0x03  
#define FC_READ_INPUT_REGISTERS      0x04
#define FC_FORCE_SINGLE_COIL         0x05
#define FC_PRESET_SINGLE_REGISTER    0x06
#define FC_READ_EXCEPTION_STATUS     0x07
#define FC_FORCE_MULTIPLE_COILS      0x0F
#define FC_PRESET_MULTIPLE_REGISTERS 0x10
#define FC_REPORT_SLAVE_ID           0x11

/* Protocol exceptions */
#define ILLEGAL_FUNCTION        -0x01
#define ILLEGAL_DATA_ADDRESS    -0x02
#define ILLEGAL_DATA_VALUE      -0x03
#define SLAVE_DEVICE_FAILURE    -0x04
#define SERVER_FAILURE          -0x04
#define ACKNOWLEDGE             -0x05
#define SLAVE_DEVICE_BUSY       -0x06
#define SERVER_BUSY             -0x06
#define NEGATIVE_ACKNOWLEDGE    -0x07
#define MEMORY_PARITY_ERROR     -0x08
#define GATEWAY_PROBLEM_PATH    -0x0A
#define GATEWAY_PROBLEM_TARGET  -0x0B

/* Local */
#define COMM_TIME_OUT           -0x0C
#define PORT_SOCKET_FAILURE     -0x0D
#define SELECT_FAILURE          -0x0E
#define TOO_MANY_DATAS          -0x0F
#define INVALID_CRC             -0x10
#define INVALID_EXCEPTION_CODE  -0x11

/* Internal using */
#define MSG_SIZE_UNDEFINED -1

typedef enum { RTU, TCP } type_com_t;
typedef enum { RECONNECT_ON_ERROR, NOP_ON_ERROR } error_handling_t;

/* This structure is byte-aligned */
typedef struct {
        /* Communication : RTU or TCP */
        type_com_t type_com;

        /* Device: "/dev/ttyS0", "/dev/ttyUSB0" or "/dev/tty.USA19*"
           on Mac OS X for KeySpan USB<->Serial adapters this string
           had to be made bigger on OS X as the directory+file name
           was bigger than 19 bytes. Making it 67 bytes for now, but
           OS X does support 256 byte file names. May become a problem
           in the future. */
#ifdef __APPLE_CC__
        char device[67];
#else
        char device[19];
#endif

        /* Parity: "even", "odd", "none" */
        char parity[5];
        /* Bauds: 19200 */
        int baud_i;
        /* Data bit */
        int data_bit;
        /* Stop bit */
        int stop_bit;
        /* Save old termios settings */
        struct termios old_tios;
        /* Descriptor (tty or socket) */
        int fd;
        /* Flag debug */
        int debug;
        /* IP address */
        char ip[16];
        /* TCP port */
        uint16_t port;
        /* Header length used for offset */
        int header_length;
        /* Checksum size RTU = 2 and TCP = 0 */
        int checksum_size;
        /* In error_treat with TCP, do a reconnect or just dump the error */
        error_handling_t error_handling;
} modbus_param_t;

typedef struct {
        int nb_coil_status;
        int nb_input_status;
        int nb_input_registers;
        int nb_holding_registers;
        unsigned char *tab_coil_status;
        unsigned char *tab_input_status;
        unsigned short *tab_input_registers;
        unsigned short *tab_holding_registers;
} modbus_mapping_t;

/* All functions used for sending or receiving data return :
   - the numbers of values (bits or word) if success (0 or more)
   - less than 0 for exceptions errors
*/

/* Reads the boolean status of coils and sets the array elements in
   the destination to TRUE or FALSE */
int read_coil_status(modbus_param_t *mb_param, int slave,
                     int start_addr, int count, int *dest);

/* Same as read_coil_status but reads the slaves input table */
int read_input_status(modbus_param_t *mb_param, int slave,
                      int start_addr, int count, int *dest);

/* Reads the holding registers in a slave and put the data into an
   array */
int read_holding_registers(modbus_param_t *mb_param, int slave,
                           int start_addr, int count, int *dest);


/* Reads the input registers in a slave and put the data into an
   array */
int read_input_registers(modbus_param_t *mb_param, int slave,
                         int start_addr, int count, int *dest);

/* Turns on or off a single coil on the slave device */
int force_single_coil(modbus_param_t *mb_param, int slave,
                      int coil_addr, int state);

/* Sets a value in one holding register in the slave device */
int preset_single_register(modbus_param_t *mb_param, int slave,
                           int reg_addr, int value);

/* Takes an array of ints and sets or resets the coils on a slave
   appropriatly */
int force_multiple_coils(modbus_param_t *mb_param, int slave,
                         int start_addr, int coil_count, int *data);

/* Copy the values in an array to an array on the slave */
int preset_multiple_registers(modbus_param_t *mb_param, int slave,
                              int start_addr, int reg_count, int *data);

/* Returns some useful information about the modbus controller */
int report_slave_id(modbus_param_t *mb_param, int slave,
                    unsigned char *dest);

/* Initialises a parameters structure
   - device : "/dev/ttyS0"
   - baud :   19200
   - parity : "even", "odd" or "none" 
   - data_bits : 5, 6, 7, 8 
   - stop_bits : 1, 2
*/
void modbus_init_rtu(modbus_param_t *mb_param, char *device,
                     int baud, char *parity, int data_bit,
                     int stop_bit);
                     
/* Initialises a parameters structure for TCP
   - ip : "192.168.0.5" 
   - port : 1099

   Set the port to MODBUS_TCP_DEFAULT_PORT to use the default one
   (502). It's convenient to use a port number greater than or equal
   to 1024 because it's not necessary to be root to use this port
   number.
*/
void modbus_init_tcp(modbus_param_t *mb_param, char *ip_address, uint16_t port);

/* By default, the error handling mode used is RECONNECT_ON_ERROR.

   With RECONNECT_ON_ERROR, the library will attempt an immediate
   reconnection which may hang for several seconds if the network to
   the remote target unit is down.

   With NOP_ON_ERROR, it is expected that the application will
   check for network error returns and deal with them as necessary.

   This function is only useful in TCP mode.
 */
void modbus_set_error_handling(modbus_param_t *mb_param, error_handling_t error_handling);

/* Sets up a serial port for RTU communications to modbus or a TCP
   connexion */
int modbus_connect(modbus_param_t *mb_param);

/* Closes the serial port and restores the previous port configuration
   or close the TCP connexion */
void modbus_close(modbus_param_t *mb_param);

/* Sets debug mode */
void modbus_set_debug(modbus_param_t *mb_param, int boolean);

/* Slave/client functions */
int modbus_mapping_new(modbus_mapping_t *mb_mapping,
                       int nb_coil_status, int nb_input_status,
                       int nb_input_registers, int nb_holding_registers);
void modbus_mapping_free(modbus_mapping_t *mb_mapping);

int modbus_init_listen_tcp(modbus_param_t *mb_param);

int modbus_listen(modbus_param_t *mb_param, unsigned char *query, int *query_size);

void manage_query(modbus_param_t *mb_param, unsigned char *query,
                  int query_size, modbus_mapping_t *mb_mapping);

/* Not implemented :
   - read_exception_status()
*/

#endif  /* _MODBUS_H_ */