diff --git a/app/include/better_log.h b/app/include/better_log.h
index 98b30e8..13e7311 100755
--- a/app/include/better_log.h
+++ b/app/include/better_log.h
@@ -91,6 +91,7 @@ typedef enum
     LOG_STORAGE,
     LOG_DEBUG,
     LOG_UPGRADE,
+    LOG_MODBUS,
     LOG_MAX
 } LOG_MODULE_E;
 
diff --git a/app/include/dbg.h b/app/include/dbg.h
index af39bfc..efad35c 100755
--- a/app/include/dbg.h
+++ b/app/include/dbg.h
@@ -68,6 +68,9 @@ typedef enum
     DBG_M_PD_UPGRADE,
     DBG_M_PD_HF,
     DBG_M_PD_HF_ERR,
+    DBG_M_SERIAL,
+    DBG_M_PD_MODBUS,
+    DBG_M_PD_MODBUS_ERR,
     DBG_M_COUNT
 } DBG_MODULE_E;
 
diff --git a/app/include/hwgpio.h b/app/include/hwgpio.h
old mode 100644
new mode 100755
index 9847498..7d9dc19
--- a/app/include/hwgpio.h
+++ b/app/include/hwgpio.h
@@ -44,6 +44,7 @@
 #define GPIO_DIR_OUT 2
 
 #define GPIO_WATCHDONG 915
+#define GPIO_485_BUS    154 // GPIO4_D2 (4*32+3*8+2)
 
 /* Exported types ------------------------------------------------------------*/
 /* 记录每个打开的gpio信息 */
@@ -57,8 +58,10 @@ typedef struct
 } gpio_node_t;
 
 /* Exported macro ------------------------------------------------------------*/
+#define GPIO_485BUS(_v_) gpio_val_set(gpio_485bus_idx, _v_)
 
 /* Extern global variables ---------------------------------------------------*/
+extern int32_t gpio_485bus_idx;
 
 /* Extern functions ----------------------------------------------------------*/
 extern int32_t gpio_val_set(uint16_t gpio, uint8_t value);
diff --git a/app/include/pd_modbus.h b/app/include/pd_modbus.h
new file mode 100755
index 0000000..832c3ca
--- /dev/null
+++ b/app/include/pd_modbus.h
@@ -0,0 +1,49 @@
+#ifndef __PD_MODBUS_H__
+#define __PD_MODBUS_H__
+
+#ifdef CFG_DEV_TYPE_LAND_PD
+
+#define WRITE       1
+#define READ        0
+
+#define MODBUS_IR_CURRENT_ADDR      0x0     // 铁芯
+#define MODBUS_IR_CURRENT_LEN       2
+#define MODBUS_DC_CURRENT_ADDR      0x34    // 直流偏磁
+#define MODBUS_DC_CURRENT_LEN       2
+
+#define MODBUS_UNIT_IR 0x01
+
+#define MODBUS_CURRENT_LEN  4
+#define MODBUS_ADDR_ALARM   0x32
+#define MODBUS_ALARM_LEN    2
+
+
+// 定义Modbus TCP MBAP头
+//#pragma pack(push, 1)
+typedef struct 
+{
+    uint16_t transaction_id;    // 事务处理标识
+    uint16_t protocol_id;       // 协议标识
+    uint16_t length;            // 数据长度
+    uint8_t unit_id;            // 设备地址
+    uint8_t function_code;      // 功能码
+} modbus_tcp_t;
+//#pragma pack(pop)
+
+typedef struct
+{
+    uint8_t function;
+    uint16_t address;
+    uint16_t length;
+} pdu_t;
+
+typedef struct
+{
+    int fd;
+    uint8_t txbuf[512];
+    uint8_t rxbuf[512];
+}modbus_t;
+
+extern int32_t modbus_handle_init_after(void);
+#endif
+#endif
diff --git a/app/include/serial.h b/app/include/serial.h
new file mode 100755
index 0000000..4b3bbe5
--- /dev/null
+++ b/app/include/serial.h
@@ -0,0 +1,33 @@
+#ifndef __SERIAL_H__
+#define __SERIAL_H__
+
+/* Includes ------------------------------------------------------------------*/
+
+/* Define --------------------------------------------------------------------*/
+
+/* Exported types ------------------------------------------------------------*/
+
+typedef struct 
+{
+    char    tty[20];                //tty: 0, 1, 2, 3, 4, 5, 6, 7
+    unsigned int   baudrate;        //baudrate
+    unsigned char  prompt;          //prompt after reciving data
+    unsigned char  databit;         //data bits, 5, 6, 7, 8
+    unsigned char  debug;           //debug mode, 0: none, 1: debug
+    unsigned char  echo;            //echo mode, 0: none, 1: echo
+    unsigned char  fctl;            //flow control, 0: none, 1: hardware, 2: software
+    unsigned char  parity;          //parity 0: none, 1: odd, 2: even
+    unsigned char  stopbit;         //stop bits, 1, 2
+    unsigned char  reserved;
+} serial_attr_t;
+
+/* Exported macro ------------------------------------------------------------*/
+
+/* Extern global variables ---------------------------------------------------*/
+
+/* Extern functions ----------------------------------------------------------*/
+extern int serial_open(const char * devname, int baudrate);
+extern int serial_read(int fd, unsigned char * data, int len);
+extern int serial_write(int fd, unsigned char * data, int len);
+extern void serial_close(int fd);
+#endif
diff --git a/app/lib/a_process/pd_main.c b/app/lib/a_process/pd_main.c
index 6877c90..fe35d8b 100755
--- a/app/lib/a_process/pd_main.c
+++ b/app/lib/a_process/pd_main.c
@@ -53,6 +53,7 @@
 #include "pd_main.h"
 #include "pd_dau.h"
 #include "pd_dbg.h"
+#include "pd_modbus.h"
 
 /* Private typedef -----------------------------------------------------------*/
 
@@ -636,6 +637,7 @@ int32_t pd_main_after(void)
     rv |= dau_handle_init_after();
     rv |= csg_handle_init_after();
     rv |= debug_handle_init_after();
+    rv |= modbus_handle_init_after();
     rv |= _pd_broadcast_init();
     
     return rv;
diff --git a/app/lib/a_process/pd_modbus.c b/app/lib/a_process/pd_modbus.c
new file mode 100755
index 0000000..bccf3a1
--- /dev/null
+++ b/app/lib/a_process/pd_modbus.c
@@ -0,0 +1,163 @@
+/* Includes ------------------------------------------------------------------*/
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef CFG_DEV_TYPE_LAND_PD
+/* 标准C库头文件. */
+#include <arpa/inet.h>
+
+/* 用户代码头文件. */
+#include "hwgpio.h"
+#include "serial.h"
+#include "pd_modbus.h"
+
+/* Private variables ---------------------------------------------------------*/
+modbus_t modbus;
+
+int32_t _modbus_tcp_transaction(uint16_t transaction_id, uint8_t unit_id, 
+    uint16_t start_addr, uint16_t data_num) 
+{
+    int txlen = 0;
+    int rxlen = 0;
+    modbus_tcp_t *frame = (modbus_tcp_t *)modbus.txbuf;
+    uint8_t *pdata = NULL;
+    uint8_t datalen = 0;
+    frame->transaction_id = htons(transaction_id);
+    frame->protocol_id = htons(0); // Modbus
+    // 长度：unit_id（1字节） + 后续PDU（5字节：功能码1 + 起始地址2 + 数量2）
+    frame->length = htons(6);
+    frame->unit_id = unit_id;
+    // PDU
+    frame->function_code = 0x03; 
+    pdata = modbus.txbuf + sizeof(modbus_tcp_t);
+    pdata[datalen++] = (start_addr >> 8) & 0xFF;  // 起始地址高字节
+    pdata[datalen++] = start_addr & 0xFF;         // 起始地址低字节
+    pdata[datalen++] = (data_num >> 8) & 0xFF;    // 数据数量高字节
+    pdata[datalen++] = data_num & 0xFF;           // 数据数量低字节
+
+    txlen = datalen + sizeof(modbus_tcp_t);
+    
+    // 发送请求帧
+    GPIO_485BUS(WRITE);
+    if (serial_write(modbus.fd, modbus.txbuf, txlen) < 0)
+    {
+        DBG(DBG_M_PD_MODBUS_ERR, "Modbus write error\r\n");
+        return E_ERROR;
+    }
+    DBG(DBG_M_PD_MODBUS_ERR, "Modbus write len = %d\r\n", txlen);
+    buf_print((char *)modbus.txbuf, txlen);
+    
+    // 等待传输完成
+    usleep(13000);  // 13000
+
+    GPIO_485BUS(READ);
+    rxlen = serial_read(modbus.fd, modbus.rxbuf, sizeof(modbus.rxbuf));
+    if (rxlen > 0)
+    {
+        DBG(DBG_M_PD_MODBUS_ERR, "Modbus read len = %d\r\n", rxlen);
+        buf_print((char *)modbus.rxbuf, rxlen);
+    }
+        
+    return E_NONE;
+}
+
+int32_t _modbus_rtu_transaction(void) 
+{
+    int sndlen = 0;
+    int rcvlen = 0;
+    uint8_t *ptxbuf = modbus.txbuf;
+    ptxbuf[sndlen++] = 0x05;
+    ptxbuf[sndlen++] = 0x03;
+    ptxbuf[sndlen++] = 0x00;
+    ptxbuf[sndlen++] = 0x34;
+    ptxbuf[sndlen++] = 0x00;
+    ptxbuf[sndlen++] = 0x02;
+    ptxbuf[sndlen++] = 0x84;
+    ptxbuf[sndlen++] = 0x41;
+
+    // 发送请求帧
+    GPIO_485BUS(WRITE);
+    if (serial_write(modbus.fd, ptxbuf, sndlen) < 0)
+    {
+        DBG(DBG_M_PD_MODBUS_ERR, "Modbus write error\r\n");
+        return E_ERROR;
+    }
+    
+    usleep(10000);
+
+    GPIO_485BUS(READ);
+    rcvlen = serial_read(modbus.fd, modbus.rxbuf, sizeof(modbus.rxbuf));
+    if (rcvlen > 0)
+    {
+        DBG(DBG_M_PD_MODBUS_ERR, "Modbus read len = %d\r\n", rcvlen);
+        buf_print((char *)modbus.rxbuf, rcvlen);
+    }
+   
+    return E_NONE;
+}
+
+void *_modbus_send_handle()
+{
+    while (1)
+    {
+#if 0
+        for (int unit = 1; unit <= 6; unit++)
+        {
+            if (_modbus_tcp_transaction(0, unit, MODBUS_ADDR_CURRENT, MODBUS_CURRENT_LEN) > 0)
+            {
+
+            }
+
+            if (_modbus_tcp_transaction(0, unit, MODBUS_ADDR_CURRENT, MODBUS_CURRENT_LEN) > 0)
+            {
+
+            }
+         }
+#else
+        //_modbus_rtu_transaction();
+
+        _modbus_tcp_transaction(5, MODBUS_UNIT_IR, MODBUS_IR_CURRENT_ADDR, MODBUS_IR_CURRENT_LEN);
+#endif
+        sleep(2);
+    }
+
+    if (modbus.fd > 0)
+    {
+        close(modbus.fd);
+        modbus.fd = -1;
+    }
+}
+
+int32_t modbus_handle_init(void)
+{
+    memset(&modbus, 0, sizeof(modbus));
+    modbus.fd = -1;
+    return E_NONE;
+}
+
+int32_t modbus_handle_init_after(void)
+{
+    int baud_rate = 9600;
+    thread_param_t param = {0};
+
+    // 初始化串口
+    int fd = serial_open("/dev/ttyS0", baud_rate);
+    if (fd < 0) 
+    {
+        DBG(DBG_M_PD_MODBUS_ERR, "Failed to initialize serial port\n");
+        return E_ERROR;
+    }
+    modbus.fd = fd;
+    DBG(DBG_M_PD_MODBUS, "fd=%d\n", modbus.fd);
+
+    param.arg = NULL;
+    param.priority = 80;
+    param.log_module = LOG_MODBUS;
+    snprintf(param.thread_name, THREAD_NAME_LEN, "MODBUS_SEND");
+    create_thread(_modbus_send_handle, &param);
+    return E_NONE;
+}
+
+#endif
+
diff --git a/app/lib/m_management/better_log.c b/app/lib/m_management/better_log.c
index 6285173..0490895 100755
--- a/app/lib/m_management/better_log.c
+++ b/app/lib/m_management/better_log.c
@@ -88,6 +88,7 @@ static const log_module_t log_module_names[] =
     {LOG_STORAGE, "STORAGE"},
     {LOG_DEBUG, "DEBUG"},
     {LOG_UPGRADE, "UPGRADE"},
+    {LOG_MODBUS, "MODBUS"},
     {-1, NULL}
 };
 
diff --git a/app/lib/m_management/dbg.c b/app/lib/m_management/dbg.c
index 0dc83bf..e477dc3 100755
--- a/app/lib/m_management/dbg.c
+++ b/app/lib/m_management/dbg.c
@@ -72,6 +72,9 @@ dbg_module_t _dbg_module[DBG_M_COUNT] =
     {DBG_M_PD_UPGRADE, FALSE, "upgrade"},
     {DBG_M_PD_HF, FALSE, "pd_hf"},
     {DBG_M_PD_HF_ERR, TRUE, "pd_hf_err"},
+    {DBG_M_SERIAL, TRUE, "serial"},
+    {DBG_M_PD_MODBUS, TRUE, "pd_modbus"},
+    {DBG_M_PD_MODBUS_ERR, TRUE, "pd_modbus_err"},
 };
 
 /* Private function prototypes -----------------------------------------------*/
diff --git a/app/lib/z_hardware/hwgpio.c b/app/lib/z_hardware/hwgpio.c
old mode 100644
new mode 100755
index 2a3906e..c0a3f9b
--- a/app/lib/z_hardware/hwgpio.c
+++ b/app/lib/z_hardware/hwgpio.c
@@ -55,6 +55,8 @@
 /* Private variables ---------------------------------------------------------*/
 static array_t *gpios = NULL;
 
+int32_t gpio_485bus_idx;
+
 /* Private function prototypes -----------------------------------------------*/
 
 /* Internal functions --------------------------------------------------------*/
@@ -327,6 +329,13 @@ int32_t gpio_export(uint16_t gpio)
 int32_t gpio_init(void)
 {
     gpios = array_init(ARRAY_MIN_SIZE, MTYPE_GPIO);
+    gpio_485bus_idx = gpio_export(GPIO_485_BUS);
+    if (gpio_485bus_idx < 0)
+    {
+        DBG(DBG_M_GPIO, "ERROR return %d!\r\n", gpio_485bus_idx);
+        return E_BAD_PARAM;
+    }
+    LD_E_RETURN(DBG_M_GPIO, gpio_dir_set(gpio_485bus_idx, GPIO_DIR_OUT));
 
     return E_NONE;
 }
diff --git a/app/lib/z_hardware/serial.c b/app/lib/z_hardware/serial.c
new file mode 100755
index 0000000..99853e6
--- /dev/null
+++ b/app/lib/z_hardware/serial.c
@@ -0,0 +1,288 @@
+/* Includes ------------------------------------------------------------------*/
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+/* 标准C库头文件. */
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <termios.h>
+
+/* 用户代码头文件. */
+#include "serial.h"
+
+int serial_band_convert(unsigned int baudrate)
+{
+    switch (baudrate)
+    {
+    case 2400:
+        return B2400;
+
+    case 4800:
+        return B4800;
+
+    case 9600:
+        return B9600;
+
+    case 19200:
+        return B19200;
+
+    case 38400:
+        return B38400;
+
+    case 57600:
+        return B57600;
+
+    case 115200:
+        return B115200;
+        
+    case 921600:
+        return B921600;
+
+    case 1152000:
+        return B1152000;
+
+    default:
+        return B115200;
+    }
+}
+
+int serial_attr_set(int fd, serial_attr_t * attr)
+{
+    unsigned char  databit  = 0;
+    unsigned char  stopbit  = 0;
+    unsigned char  parity   = 0;
+    unsigned char  fctl     = 0;
+    int  ret = -1;
+    unsigned int baudrate = 0;
+
+    struct termios termios_old;
+    struct termios termios_new;
+
+    memset(&termios_old, 0, sizeof(termios_old));
+    memset(&termios_new, 0, sizeof(termios_new));
+
+    cfmakeraw(&termios_new);
+
+    if (tcgetattr(fd, &termios_old) != 0)
+    {
+        DBG(DBG_M_SERIAL, "Setup Serial!\r\n");
+        return ret;
+    }
+
+    //baudrates
+    baudrate = serial_band_convert(attr->baudrate);
+    cfsetispeed(&termios_new, baudrate);
+    cfsetospeed(&termios_new, baudrate);
+    termios_new.c_cflag |= CLOCAL;
+    termios_new.c_cflag |= CREAD;
+
+    //flow control
+    fctl = attr-> fctl;
+    switch (fctl)
+    {
+    case 0:
+        termios_new.c_cflag &= ~CRTSCTS;        //no flow control
+        break;
+    case 1:
+        termios_new.c_cflag |= CRTSCTS;         //hardware flow control
+        break;
+
+    case 2:
+        termios_new.c_iflag |= IXON | IXOFF | IXANY; //software flow control
+        break;
+    }
+
+    //data bits
+    termios_new.c_cflag &= ~CSIZE;      //控制模式，屏蔽字符大小位
+    databit = attr->databit;
+    switch (databit)
+    {
+    case 5:
+        termios_new.c_cflag |= CS5;
+        break;
+
+    case 6:
+        termios_new.c_cflag |= CS6;
+        break;
+
+    case 7:
+        termios_new.c_cflag |= CS7;
+        break;
+
+    case 8:
+        termios_new.c_cflag |= CS8;
+        break;
+
+    default:
+        termios_new.c_cflag |= CS8;
+        break;
+    }
+
+    //parity check
+    parity = attr->parity;
+    switch (parity)
+    {
+    case 0:             //no parity check
+        termios_new.c_cflag &= ~PARENB;
+        break;
+
+    case 1:             //odd check
+        termios_new.c_cflag |= PARENB;
+        termios_new.c_cflag &= ~PARODD;
+        break;
+
+    case 2:             //even check
+        termios_new.c_cflag |= PARENB;
+        termios_new.c_cflag |= PARODD;
+        break;
+    }
+
+    //stop bits
+    stopbit = attr->stopbit;
+    if (stopbit == 2)
+    {
+        termios_new.c_cflag |= CSTOPB;
+    }
+    else if (stopbit == 1)
+    {
+        termios_new.c_cflag &= ~CSTOPB;
+    }
+
+    //other attributions default
+    termios_new.c_oflag &= ~OPOST;
+    termios_new.c_cc[VMIN]  = 1;
+    termios_new.c_cc[VTIME] = 1;
+    tcflush(fd, TCIFLUSH);
+    ret = tcsetattr(fd, TCSANOW, &termios_new);
+
+    return ret;
+}
+
+int serial_open(const char * devname, int baudrate)
+{
+    int fd;
+    serial_attr_t attr;
+    fd = open(devname, O_RDWR | O_NOCTTY | O_NONBLOCK);
+    if (fd < 0)
+    {
+        DBG(DBG_M_SERIAL, "Open SerialPort(%s) failed[error = %d, %s]!!!!!!!\r\n",
+            devname, errno, strerror(errno));
+        return E_SYS_CALL;
+    }
+
+    strcpy(attr.tty, devname);
+    attr.baudrate = baudrate;
+
+    serial_attr_set(fd, &attr);
+
+    DBG(DBG_M_SERIAL, "Open SerialPort(%s:%d) port success!!!\r\n", devname, baudrate);
+
+    return fd;
+}
+
+int serial_read(int fd, unsigned char * data, int len)
+{
+    int ret = -1;
+    fd_set fs_read;
+    int maxfd = -1;
+
+    if (fd < 0 || data == NULL || len <= 0)
+    {
+        DBG(DBG_M_SERIAL, "Param Error, fd = %d or NULL == data or len <= 0.\r\n", fd);
+        return E_ERROR;
+    }
+    
+    FD_ZERO(&fs_read);
+    FD_SET(fd, &fs_read);
+    maxfd = fd + 1;
+    struct timeval tv;
+    tv.tv_sec = 0;
+    tv.tv_usec = 1000 * 1000;
+
+    ret = select(maxfd, &fs_read, NULL, NULL, &tv);
+    if (ret < 0)
+    {
+        DBG(DBG_M_SERIAL, "select error[%d, %s]!!!\r\n", errno, strerror(errno));
+        return E_SYS_CALL;
+    }
+
+    if (ret == 0)
+    {
+        DBG(DBG_M_SERIAL, "Timeout......\r\n");
+        return E_TIMEOUT;
+    }
+
+    ret = read(fd, data, len);
+    if (ret < 0)
+    {
+        DBG(DBG_M_SERIAL, "read error[%d, %s]\r\n", errno, strerror(errno));
+        return E_SYS_CALL;
+    }    
+
+    return ret;
+}
+
+int serial_write(int fd, unsigned char * data, int len)
+{
+    if (fd < 0 || NULL == data || len <= 0)
+    {
+        DBG(DBG_M_SERIAL, "Param Error, fd = %d or NULL == data or len = %d.\r\n", fd, len);
+        return E_BAD_PARAM;
+    }
+
+    fd_set  fs_write;
+    FD_ZERO(&fs_write);
+    FD_SET(fd, &fs_write);
+
+    int maxfd = fd + 1;
+    struct timeval tv;
+    tv.tv_sec = 0;
+    tv.tv_usec = 1000 * 1000;
+
+    int ret = select(maxfd, NULL, &fs_write, NULL, &tv);
+    if (ret < 0)
+    {
+        DBG(DBG_M_SERIAL, "select Error[errno = %d, %s]\r\n", errno, strerror(errno));
+        return E_SYS_CALL;
+    }
+    else if (ret == 0)
+    {
+        DBG(DBG_M_SERIAL, "Timeout!\r\n");
+        return E_TIMEOUT;
+    }
+
+    if (FD_ISSET(fd, &fs_write))
+    {
+        int pos = 0;
+
+        while (len > 0)
+        {
+            ret = write(fd, data + pos, len);
+            if (ret < 0)
+            {
+                DBG(DBG_M_SERIAL, "write com[fd = %d] error[errno = %d, %s]\r\n", fd, errno, strerror(errno));
+                return E_SYS_CALL;
+            }
+            len -= ret;
+            pos += ret;
+        }
+    }
+
+    return len;
+}
+
+void serial_close(int fd)
+{
+    if (fd > 0)
+    {
+        close(fd);
+    }
+}
+
+