使用freemodbus无法读取寄存器数据

发布于 2020-06-24 17:30:34 浏览：1971 订阅该版

4 个回答

whj467467222 认证专家 2020-06-24

开源，分享，交流，共同进步

shouzhou 2020-06-25

这家伙很懒，什么也没写！

shouzhou 2020-06-26

这家伙很懒，什么也没写！

今天测试了一下，还是不行，后来我把别的进程都关闭了，似乎也不对，肯定那里有问题，把读写放到单独的一个进程里面的代码在下面：
static void send_thread_entry(void *parameter)
{
    eMBMasterReqErrCode error_code = MB_MRE_NO_ERR;
    rt_uint16_t error_count = 0;
    USHORT data[10] = {0};
    rt_uint8_t  i =0;
    USHORT test = 0x0000;
    while (1)
    {
        
        error_code =  eMBMasterReqReadHoldingRegister( 
                                             SLAVE_ADDR,
                                             MB_READ_REG_START, 
                                             MB_READ_REG_NUM, 
                                             RT_WAITING_FOREVER);

/* Record the number of errors */
        if (error_code != MB_MRE_NO_ERR)
        {
            error_count++;
            rt_kprintf("READ fail= %d\r\n",error_code);
        }
        else
        {
            rt_kprintf("READ ok\r\n");
        }
        
        data[0] = usMRegHoldBuf[0][0];
        data[1] = usMRegHoldBuf[0][1];
        data[2] = usMRegHoldBuf[0][2];
        data[3] = usMRegHoldBuf[0][3];
        data[4] = usMRegHoldBuf[0][4];
        data[5] = usMRegHoldBuf[0][5];
        data[6] = usMRegHoldBuf[0][6];
        data[7] = usMRegHoldBuf[0][7];
        data[8] = usMRegHoldBuf[0][8];
        data[9] = usMRegHoldBuf[0][9];

error_code = eMBMasterReqWriteMultipleHoldingRegister(SLAVE_ADDR,          /* salve address */
                                                              MB_SEND_REG_START,   /* register start address */
                                                              MB_SEND_REG_NUM,     /* register total number */
                                                              data,                /* data to be written */
                                                              RT_WAITING_FOREVER); /* timeout */
        if (error_code != MB_MRE_NO_ERR)
        {
            error_count++;
             rt_kprintf("WRITE fail= %d\r\n",error_code);
        }
        else
        {
            rt_kprintf("WRITE ok\r\n");
        }

test = test +0x0100;
        rt_thread_mdelay(1000);
    }
}
用list_thread 的进程显示如下：
list_thread
thread           pri  status      sp     stack size max used left tick  error
---------------- ---  ------- ---------- ----------  ------  ---------- ---
md_m_send         20  suspend 0x000000e4 0x00000200    44%   0x00000013 000
master_trans      10  suspend 0x000000a4 0x00000200    32%   0x00000002 000
md_m_poll          9  suspend 0x0000007c 0x00000200    59%   0x00000032 000
tshell            20  running 0x00000080 0x00001000    12%   0x00000003 000
tidle0            31  ready   0x00000050 0x00000100    34%   0x00000001 000

测试后读写的成功率如下，读2个寄存器  写 10个寄存器：
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE ok
READ ok
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE ok
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE ok
READ fail= 3
WRITE ok
READ fail= 3
WRITE ok
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ ok
WRITE ok
READ ok
WRITE ok
READ ok
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ fail= 3
WRITE fail= 3
READ ok

这个ok 是正确的 3 是MB_MRE_REV_DATA 这个错误