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#include <modbus.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>


int main(void)
{
    modbus_t *ctx=NULL;     // context
    int addr=0;             // address
    int rc=0;               // received
    int nb = 3;             // the number of bit

    uint16_t *tab_rq_registers=NULL;
    uint16_t *tab_rp_registers=NULL;

    /* RTU */
    ctx = modbus_new_rtu("/dev/ttySAC3",9600,'N',8,1);
    modbus_set_debug(ctx, TRUE);
    modbus_set_slave(ctx, 0x01);  // 设置从机地址

    // connect
    if (-1 == modbus_connect(ctx))
    {
        fprintf(stderr, "Conncetion failed: %s\n", modbus_strerror(errno));
        modbus_free(ctx);
        return -1;
    }

    // 读取数据
    uint16_t tab_reg[2];  // 存放要读的数据
    int regs=modbus_read_registers(ctx,0,2,tab_reg);

    /* Close the connection */
    modbus_close(ctx);
    modbus_free(ctx);

    return 0;
}

/*
 * The client of modbus tcp.
 * test 2 register
 *
 * 2017-10-26
 */

#include <modbus.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>


int main(void)
{
    modbus_t *ctx=NULL;     // context
    int addr=0;             // address
    int rc=0;               // received
    int nb = 3;             // the number of bit

    uint16_t *tab_rq_registers=NULL;
    uint16_t *tab_rp_registers=NULL;

    /* TCP */
    ctx = modbus_new_tcp("192.168.2.29", 1502);
    modbus_set_debug(ctx, TRUE);
    // connect
    if (-1 == modbus_connect(ctx))
    {
        fprintf(stderr, "Conncetion failed: %s\n", modbus_strerror(errno));
        modbus_free(ctx);
        return -1;
    }

    /* Allocate and initialize the memory spaces. */
    tab_rq_registers = (uint16_t *) malloc(nb * sizeof(uint16_t));
    memset(tab_rq_registers, 0, nb * sizeof(uint16_t));
    tab_rp_registers = (uint16_t *) malloc(nb * sizeof(uint16_t));
    memset(tab_rp_registers, 0, nb * sizeof(uint16_t));


    // write
    tab_rq_registers[0] = 25;
    tab_rq_registers[1] = 2;
    tab_rq_registers[2] = 88;


    rc = modbus_write_registers(ctx, addr, nb, tab_rq_registers);
    if (rc != nb)
    {
        printf("ERROR modbus_write_bits single (%d)\n", rc);
        printf("address = %d\n", addr);
    }

    // read
    rc = modbus_read_registers(ctx, addr, nb, tab_rp_registers);
    if (rc != nb)
    {
        printf("ERROR modbus_read_bits single (%d)\n", rc);
        printf("address = %d\n", addr);
    }
    for (int i = 0; i < nb; ++i)
    {
        printf("%d%c", tab_rp_registers[i], (i==nb-1)?'\n':' ');
    }   
        
    free(tab_rq_registers);
    free(tab_rp_registers);
    /* Close the connection */
    modbus_close(ctx);
    modbus_free(ctx);
    
    return 0;
}