diff --git a/components/sensors/smtp2/smtp2.cpp b/components/sensors/smtp2/smtp2.cpp
index e78b00e..4b6533d 100644
--- a/components/sensors/smtp2/smtp2.cpp
+++ b/components/sensors/smtp2/smtp2.cpp
@@ -9,7 +9,7 @@
 using namespace iflytop;
 #define TAG "SMTP2"
 
-#define OVERTIME 20
+#define OVERTIME 30
 #define DUMP_HEX 1
 
 /**
@@ -158,7 +158,7 @@ int32_t SMTP2::readparaint(int32_t paramidx, int32_t& val) {
   size_t rxlen = 0;
   int    ret   = sendcmd(fmt("/1?%d\r", paramidx), m_rxbuf, sizeof(m_rxbuf), rxlen);
   if (ret != 0) {
-    return -1;
+    return ret;
   }
   iflytop::err::error_t ecode = read_ack_error_code(m_rxbuf, rxlen);
   if (ecode != err::ksucc) {
@@ -228,18 +228,19 @@ char* SMTP2::fmt(const char* fmt, ...) {
 int32_t SMTP2::getState(bool& isbusy, err::error_t& error) {
   size_t rxlen = 0;
   sprintf(txbuf, "/1Q\r");
-  int ret = sendcmd(txbuf, strlen(txbuf), m_rxbuf, sizeof(m_rxbuf), rxlen);
+  int ret = sendcmd(txbuf, m_rxbuf, sizeof(m_rxbuf), rxlen);
   if (ret != 0) {
-    return -1;
+    return ret;
   }
   uint8_t errorcode = (uint8_t)m_rxbuf[2];
-  if (errorcode > '`') {
+  if (errorcode >= '`') {
     isbusy    = false;
     errorcode = errorcode - '`';
-  } else if (errorcode > '@') {
+  } else if (errorcode >= '@') {
     isbusy    = true;
     errorcode = errorcode - '@';
   }
+  error = (err::error_t)errorcode;
   return 0;
 }
 
@@ -278,9 +279,9 @@ iflytop::err::error_t SMTP2::read_ack_error_code(char* rxbuf, size_t rxlen) {
     return err::kdevice_is_offline;
   }
   uint8_t errorcode = (uint8_t)rxbuf[2];
-  if (errorcode > '`') {
+  if (errorcode >= '`') {
     errorcode = errorcode - '`';
-  } else if (errorcode > '@') {
+  } else if (errorcode >= '@') {
     errorcode = errorcode - '@';
   }
   return (err::error_t)errorcode;
@@ -309,13 +310,14 @@ int32_t SMTP2::read_ack_int_val(char* rxbuf, size_t rxlen) {
 
 int32_t SMTP2::doaction(char* cmd) {
   //
-  size_t rxlen   = 0;
-  size_t txlen   = strlen(cmd);
-  cmd[txlen]     = '\r';
-  cmd[txlen + 1] = 0;
-  int ret        = sendcmd(cmd, txlen + 1, m_rxbuf, sizeof(m_rxbuf), rxlen);
+  size_t rxlen = 0;
+  size_t txlen = strlen(cmd);
+  // cmd[txlen]     = '\r';
+  cmd[txlen] = 0;
+  // cmd[txlen + 1] = 0;
+  int ret = sendcmd(cmd, m_rxbuf, sizeof(m_rxbuf), rxlen);
   if (ret != 0) {
-    return -1;
+    return ret;
   }
 
   uint8_t state = (uint8_t)m_rxbuf[2];
@@ -330,30 +332,51 @@ int32_t SMTP2::doaction(char* cmd) {
   }
   return state + err::kSMTP2_NoError;
 }
-int32_t SMTP2::sendcmd(const char* cmd, char* rxbuf, size_t rxbuflen, size_t& rxlen) { return sendcmd(cmd, strlen(cmd), rxbuf, rxbuflen, rxlen); }
-int32_t SMTP2::sendcmd(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen) {
+
+int32_t SMTP2::sendcmd(const char* cmd, char* rxbuf, size_t rxbuflen, size_t& rxlen) {
+  int32_t ecode = 0;
+  for (size_t i = 0; i < 5; i++) {
+    ecode = _sendcmd(cmd, rxbuf, rxbuflen, rxlen);
+    if (ecode == 0) {
+      break;
+    }
+    ZLOGI(TAG, "re send cmd %d", i);
+  }
+  return ecode;
+}
+
+int32_t SMTP2::_sendcmd(const char* cmd, char* rxbuf, size_t rxbuflen, size_t& rxlen) { return _sendcmd(cmd, strlen(cmd), rxbuf, rxbuflen, rxlen); }
+int32_t SMTP2::_sendcmd(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen) {
   if (!m_uart) return -1;
 
   int ret = 0;
   // size_t rxlen = 0;
 
 #ifdef DUMP_HEX
-  ZLOGI_NOT_END_LINE(TAG, "tx:%s", cmd);
+  if (strcmp("/1Q\r", cmd) != 0) {
+    ZLOGI_NOT_END_LINE(TAG, "tx:%s", cmd);
+  }
 #endif
 
   if (m_hdma_rx)
-    ret = sendcmd_dma(cmd, txlen, (char*)m_rxbuf, sizeof(m_rxbuf), rxlen);
+    ret = _sendcmd_dma(cmd, txlen, (char*)m_rxbuf, sizeof(m_rxbuf), rxlen);
   else
-    ret = sendcmd_block(cmd, txlen, (char*)m_rxbuf, sizeof(m_rxbuf), rxlen);
+    ret = _sendcmd_block(cmd, txlen, (char*)m_rxbuf, sizeof(m_rxbuf), rxlen);
 
 #ifdef DUMP_HEX
-  ZLOGI_NOT_END_LINE(TAG, "rx:%s", m_rxbuf);
+  if (strcmp("/1Q\r", cmd) != 0) {
+    ZLOGI_NOT_END_LINE(TAG, "rx:%s", m_rxbuf);
+  }
 #endif
   return ret;
 }
 
-int32_t SMTP2::sendcmd_dma(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen) {
+int32_t SMTP2::_sendcmd_dma(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen) {
   memset(rxbuf, 0, rxbuflen);
+  uint8_t rxdata;
+  // clear rx buf
+  while (HAL_UART_Receive(m_uart, &rxdata, 1, 1) == HAL_OK) {
+  }
   HAL_UART_Transmit(m_uart, (uint8_t*)cmd, txlen, 1000);
 
   uint32_t enter_ticket = HAL_GetTick();
@@ -363,19 +386,19 @@ int32_t SMTP2::sendcmd_dma(const char* cmd, size_t txlen, char* rxbuf, size_t rx
          HAL_UART_GetState(m_uart) == HAL_UART_STATE_BUSY_TX_RX) {
     osDelay(1);
     if (zos_haspassedms(enter_ticket) > OVERTIME) {
-      ZLOGW(TAG, "sendcmd_dma overtime");
+      // ZLOGW(TAG, "sendcmd_dma overtime");
       overtime_flag = true;
       break;
     }
   }
   HAL_UART_DMAStop(m_uart);
   if (overtime_flag) {
-    return -1;
+    return err::kovertime;
   }
   rxlen = rxbuflen - __HAL_DMA_GET_COUNTER(m_hdma_rx);
   return 0;
 }
-int32_t SMTP2::sendcmd_block(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen) {
+int32_t SMTP2::_sendcmd_block(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen) {
   // m_huart->tx(cmd);
   memset(rxbuf, 0, rxbuflen);
   //   printf("tx:%s\n", cmd);
@@ -385,7 +408,7 @@ int32_t SMTP2::sendcmd_block(const char* cmd, size_t txlen, char* rxbuf, size_t
   HAL_StatusTypeDef rxstatus = HAL_UART_Receive(m_uart, (uint8_t*)&rxbuf[0], 1, OVERTIME);
   if (rxstatus != HAL_OK) {
     rxlen = 0;
-    return -1;
+    return err::kovertime;
   }
   rxnum++;
   for (;; rxnum++) {
@@ -407,21 +430,37 @@ int32_t SMTP2::doaction_block(function<int32_t()> action) {
     return ret;
   }
   // 等待移液枪复位完成
+  int32_t ecodetimes = 0;
   while (true) {
-    int32_t state = getState();
-    if (state != err::kdevice_is_busy) {
-      if (state == 0) {
-        stop();
-        return 0;
-      } else {
-        stop();
-        return ret;
+    // int32_t state = getState();
+    osDelay(100);
+
+    bool         isbusy;
+    err::error_t error;
+
+    int32_t ecode = getState(isbusy, error);
+    if (ecode != 0) {
+      ecodetimes++;
+      if (ecodetimes > 3) {
+        return err::kovertime;
       }
+      continue;
+    }
+
+    if (error != 0) {
+      ZLOGI(TAG, "error:%d", error);
+      stop();
+      return error;
     }
+
+    // 动作执行完成
+    if (!isbusy) {
+      return 0;
+    }
+
     if (thisThread.getExitFlag()) {
       stop();
       return err::kmodule_opeation_break_by_user;
     }
-    thisThread.sleep(1000);
   }
 }
diff --git a/components/sensors/smtp2/smtp2.hpp b/components/sensors/smtp2/smtp2.hpp
index e455928..a0cb70b 100644
--- a/components/sensors/smtp2/smtp2.hpp
+++ b/components/sensors/smtp2/smtp2.hpp
@@ -4,39 +4,17 @@
 namespace iflytop {
 using namespace std;
 
+
+/**
+ * @brief 
+ * 
+ *  ref:https://iflytop1.feishu.cn/wiki/VNNRwUJCtiuRDHkD1uScGIA1nMf
+ *  WARNING:
+ *      1,发送消息有一定概率失败，目前没有找到原因，暂时通过重发解决，一般重发一次，即可发送成功。
+ */
 class SMTP2 {
  public:
-#if 0
-  typedef enum {
-    kNoError             = 0,   // 无错误
-    kInitFail            = 1,   // 初始化失败
-    kInvalidCmd          = 2,   // 无效命令
-    kInvalidArg          = 3,   // 无效参数
-    kPressureSensorError = 4,   // 压力传感器故障
-    kOverPressure        = 5,   // 超过压力
-    kLLDError            = 6,   // LLD 错误
-    kDeviceNotInit       = 7,   // 设备未初始化
-    kTipPopError         = 8,   // Tip 弹出错误
-    kPumpOverload        = 9,   // 泵过载
-    kTipDrop             = 10,  // Tip 脱落
-    kCanBusError         = 11,  // CAN 总线故障
-    kInvalidChecksum     = 12,  // 无效校验和
-    kEEPROMError         = 13,  // EEPROM 故障
-    kCmdBufferEmpty      = 14,  // 命令缓冲区为空
-    kCmdBufferOverflow   = 15,  // 命令溢出
-    kTipBlock            = 16,  // Tip 堵塞
-    kAirSuction          = 17,  // 吸入空气
-    kBubble              = 18,  // 液体中有气泡/泡沫
-    kVolumeError         = 19,  // 吸取/分配量不准确
-  } error_t;
-#endif
-
-#if 0
-  typedef enum {
-    kIdle = 0,
-    kBusy = 1,
-  } state_t;
-#endif
+
 
  private:
   UART_HandleTypeDef* m_uart = nullptr;
@@ -149,9 +127,11 @@ class SMTP2 {
   int32_t doaction(char* cmd);
 
   int32_t sendcmd(const char* cmd, char* rxbuf, size_t rxbuflen, size_t& rxlen);
-  int32_t sendcmd(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen);
-  int32_t sendcmd_dma(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen);
-  int32_t sendcmd_block(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen);
+
+  int32_t _sendcmd(const char* cmd, char* rxbuf, size_t rxbuflen, size_t& rxlen);
+  int32_t _sendcmd(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen);
+  int32_t _sendcmd_dma(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen);
+  int32_t _sendcmd_block(const char* cmd, size_t txlen, char* rxbuf, size_t rxbuflen, size_t& rxlen);
 
   iflytop::err::error_t read_ack_error_code(char* rxbuf, size_t rxlen);
   int32_t               read_ack_int_val(char* rxbuf, size_t rxlen);