modbus tcp fix uid settings

Kconfig

@@ -16,7 +16,7 @@ menu "Modbus configuration"
 
     config FMB_TCP_PORT_MAX_CONN
         int "Maximum allowed connections for TCP stack"
-        range 1 6
+        range 1 8
         default 5
         depends on FMB_COMM_MODE_TCP_EN
         help
@@ -34,6 +34,14 @@ menu "Modbus configuration"
                 Modbus TCP connection timeout in seconds.
                 Once expired the current connection with the client will be closed
                 and Modbus slave will be waiting for new connection to accept.
+    
+    config FMB_TCP_UID_ENABLED
+        bool "Modbus TCP enable UID (Unit Identifier) support"
+        default n
+        depends on FMB_COMM_MODE_TCP_EN
+        help
+                If this option is set the Modbus stack uses UID (Unit Identifier) field in MBAP frame.
+                Else the UID is ignored by master and slave.
 
     config FMB_COMM_MODE_RTU_EN
         bool "Enable Modbus stack support for RTU mode"

freemodbus/common/include/esp_modbus_common.h

@@ -143,6 +143,7 @@ typedef union {
     // TCP/UDP communication structure
     struct {
         mb_mode_type_t ip_mode;                /*!< Modbus communication mode */
+        uint8_t slave_uid;                     /*!< Modbus slave address field for UID */
         uint16_t ip_port;                      /*!< Modbus port */
         mb_tcp_addr_type_t ip_addr_type;       /*!< Modbus address type */
         void* ip_addr;                         /*!< Modbus address table for connection */

freemodbus/modbus/include/mb.h

@@ -165,6 +165,7 @@ eMBErrorCode    eMBInit( eMBMode eMode, UCHAR ucSlaveAddress,
  * frame processing is still disabled until eMBEnable( ) is called.
  *
  * \param usTCPPort The TCP port to listen on.
+ * \param ucSlaveUid The UID field for slave to listen on.
  * \return If the protocol stack has been initialized correctly the function
  *   returns eMBErrorCode::MB_ENOERR. Otherwise one of the following error
  *   codes is returned:
@@ -172,7 +173,7 @@ eMBErrorCode    eMBInit( eMBMode eMode, UCHAR ucSlaveAddress,
  *        slave addresses are in the range 1 - 247.
  *    - eMBErrorCode::MB_EPORTERR IF the porting layer returned an error.
  */
-eMBErrorCode    eMBTCPInit( USHORT usTCPPort );
+eMBErrorCode    eMBTCPInit( UCHAR ucSlaveUid, USHORT usTCPPort );
 
 /*! \ingroup modbus
  * \brief Release resources used by the protocol stack.

freemodbus/modbus/include/mbconfig.h

@@ -86,6 +86,10 @@ PR_BEGIN_EXTERN_C
 
 #endif
 
+/*! \brief The option is required for support of RTU over TCP.
+ */
+#define MB_TCP_UID_ENABLED                      (  CONFIG_FMB_TCP_UID_ENABLED )
+
 /*! \brief This option defines the number of data bits per ASCII character.
  *
  * A parity bit is added before the stop bit which keeps the actual byte size at 10 bits.

freemodbus/modbus/mb.c

@@ -202,11 +202,16 @@ eMBInit( eMBMode eMode, UCHAR ucSlaveAddress, UCHAR ucPort, ULONG ulBaudRate, eM
 
 #if MB_TCP_ENABLED > 0
 eMBErrorCode
-eMBTCPInit( USHORT ucTCPPort )
+eMBTCPInit( UCHAR ucSlaveUid, USHORT ucTCPPort )
 {
     eMBErrorCode    eStatus = MB_ENOERR;
 
-    if( ( eStatus = eMBTCPDoInit( ucTCPPort ) ) != MB_ENOERR )
+    /* Check preconditions */
+    if( ucSlaveUid > MB_ADDRESS_MAX )
+    {
+        eStatus = MB_EINVAL;
+    }
+    else if( ( eStatus = eMBTCPDoInit( ucTCPPort ) ) != MB_ENOERR )
     {
         eMBState = STATE_DISABLED;
     }
@@ -222,7 +227,7 @@ eMBTCPInit( USHORT ucTCPPort )
         peMBFrameReceiveCur = eMBTCPReceive;
         peMBFrameSendCur = eMBTCPSend;
         pvMBFrameCloseCur = MB_PORT_HAS_CLOSE ? vMBTCPPortClose : NULL;
-        ucMBAddress = MB_TCP_PSEUDO_ADDRESS;
+        ucMBAddress = ucSlaveUid;
         eMBCurrentMode = MB_TCP;
         eMBState = STATE_DISABLED;
     }
@@ -371,7 +376,8 @@ eMBPoll( void )
             if( eStatus == MB_ENOERR )
             {
                 /* Check if the frame is for us. If not ignore the frame. */
-                if( ( ucRcvAddress == ucMBAddress ) || ( ucRcvAddress == MB_ADDRESS_BROADCAST ) )
+                if( ( ucRcvAddress == ucMBAddress ) || ( ucRcvAddress == MB_ADDRESS_BROADCAST ) 
+                                            || ( ucRcvAddress == MB_TCP_PSEUDO_ADDRESS ) )
                 {
                     ( void )xMBPortEventPost( EV_EXECUTE );
                     ESP_LOG_BUFFER_HEX_LEVEL(MB_PORT_TAG, &ucMBFrame[MB_PDU_FUNC_OFF], usLength, ESP_LOG_DEBUG);
@@ -401,8 +407,8 @@ eMBPoll( void )
             }
 
             /* If the request was not sent to the broadcast address we
-             * return a reply. */
+             * return a reply. In case of TCP the slave answers to broadcast address. */
-            if( ucRcvAddress != MB_ADDRESS_BROADCAST )
+            if( ( ucRcvAddress != MB_ADDRESS_BROADCAST ) || ( eMBCurrentMode == MB_TCP ) )
             {
                 if( eException != MB_EX_NONE )
                 {

freemodbus/modbus/tcp/mbtcp.c

@@ -124,10 +124,14 @@ eMBTCPReceive( UCHAR * pucRcvAddress, UCHAR ** ppucFrame, USHORT * pusLength )
             *pusLength = usLength - MB_TCP_FUNC;
             eStatus = MB_ENOERR;
 
-            /* Modbus TCP does not use any addresses. Fake the source address such
+            /* The regular Modbus TCP does not use any addresses. Fake the MBAP UID in this case.
-             * that the processing part deals with this frame.
+             * The MBAP UID field support is used for RTU over TCP option if enabled.
              */
+#if MB_TCP_UID_ENABLED
+            *pucRcvAddress = pucMBTCPFrame[MB_TCP_UID];
+#else
             *pucRcvAddress = MB_TCP_PSEUDO_ADDRESS;
+#endif
         }
     }
     else
@@ -152,6 +156,7 @@ eMBTCPSend( UCHAR _unused, const UCHAR * pucFrame, USHORT usLength )
      */
     pucMBTCPFrame[MB_TCP_LEN] = ( usLength + 1 ) >> 8U;
     pucMBTCPFrame[MB_TCP_LEN + 1] = ( usLength + 1 ) & 0xFF;
+
     if( xMBTCPPortSendResponse( pucMBTCPFrame, usTCPLength ) == FALSE )
     {
         eStatus = MB_EIO;

freemodbus/modbus/tcp/mbtcp_m.c

@@ -123,10 +123,14 @@ eMBMasterTCPReceive( UCHAR * pucRcvAddress, UCHAR ** ppucFrame, USHORT * pusLeng
             *pusLength = usLength - MB_TCP_FUNC;
             eStatus = MB_ENOERR;
 
-            /* Modbus TCP does not use any addresses. Fake the source address such
+            /* Get MBAP UID field if its support is enabled.
-             * that the processing part deals with this frame.
+             * Otherwise just ignore this field.
              */
+#if MB_TCP_UID_ENABLED
+            *pucRcvAddress = pucMBTCPFrame[MB_TCP_UID];
+#else
             *pucRcvAddress = MB_TCP_PSEUDO_ADDRESS;
+#endif
         }
     }
     else
@@ -137,20 +141,27 @@ eMBMasterTCPReceive( UCHAR * pucRcvAddress, UCHAR ** ppucFrame, USHORT * pusLeng
 }
 
 eMBErrorCode
-eMBMasterTCPSend( UCHAR _unused, const UCHAR * pucFrame, USHORT usLength )
+eMBMasterTCPSend( UCHAR ucAddress, const UCHAR * pucFrame, USHORT usLength )
 {
     eMBErrorCode    eStatus = MB_ENOERR;
     UCHAR          *pucMBTCPFrame = ( UCHAR * ) pucFrame - MB_TCP_FUNC;
     USHORT          usTCPLength = usLength + MB_TCP_FUNC;
 
-    /* The MBAP header is already initialized because the caller calls this
+    /* Note that the length in the MBAP header includes the size of the Modbus PDU 
-     * function with the buffer returned by the previous call. Therefore we
+     * and the UID Byte. Therefore the length is usLength plus one.
-     * only have to update the length in the header. Note that the length
-     * header includes the size of the Modbus PDU and the UID Byte. Therefore
-     * the length is usLength plus one.
      */
     pucMBTCPFrame[MB_TCP_LEN] = ( usLength + 1 ) >> 8U;
     pucMBTCPFrame[MB_TCP_LEN + 1] = ( usLength + 1 ) & 0xFF;
+    
+    /* Set UID field in the MBAP if it is supported.
+     * If the RTU over TCP is not supported, the UID = 0 or 0xFF.
+     */
+#if MB_TCP_UID_ENABLED
+    pucMBTCPFrame[MB_TCP_UID] = ucAddress;
+#else
+    pucMBTCPFrame[MB_TCP_UID] = 0x00;
+#endif
+
     if( xMBMasterTCPPortSendResponse( pucMBTCPFrame, usTCPLength ) == FALSE )
     {
         eStatus = MB_EIO;

freemodbus/modbus/tcp/mbtcp_m.h

@@ -50,7 +50,7 @@ void            eMBMasterTCPStart( void );
 void            eMBMasterTCPStop( void );
 eMBErrorCode    eMBMasterTCPReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame,
                                USHORT * pusLength );
-eMBErrorCode    eMBMasterTCPSend( UCHAR _unused, const UCHAR * pucFrame,
+eMBErrorCode    eMBMasterTCPSend( UCHAR ucAddress, const UCHAR * pucFrame,
                             USHORT usLength );
 BOOL            xMBMasterTCPTimerExpired(void);
 

freemodbus/tcp_master/port/port_tcp_master.c

@@ -989,6 +989,7 @@ xMBMasterTCPPortSendResponse( UCHAR * pucMBTCPFrame, USHORT usTCPLength )
             // Apply TID field to the frame before send
             pucMBTCPFrame[MB_TCP_TID] = (UCHAR)(pxInfo->usTidCnt >> 8U);
             pucMBTCPFrame[MB_TCP_TID + 1] = (UCHAR)(pxInfo->usTidCnt & 0xFF);
+
             int xRes = xMBMasterTCPPortWritePoll(pxInfo, pucMBTCPFrame, usTCPLength, MB_TCP_SEND_TIMEOUT_MS);
             if (xRes < 0) {
                 ESP_LOGE(TAG, MB_SLAVE_FMT(", send data failure, err(errno) = %d(%d)."),

freemodbus/tcp_slave/modbus_controller/mbc_tcp_slave.c

@@ -72,7 +72,7 @@ static esp_err_t mbc_tcp_slave_start(void)
     eMBErrorCode status = MB_EIO;
 
     // Initialize Modbus stack using mbcontroller parameters
-    status = eMBTCPInit((USHORT)mbs_opts->mbs_comm.ip_port);
+    status = eMBTCPInit((UCHAR)mbs_opts->mbs_comm.slave_uid, (USHORT)mbs_opts->mbs_comm.ip_port);
     MB_SLAVE_CHECK((status == MB_ENOERR), ESP_ERR_INVALID_STATE,
             "mb stack initialization failure, eMBInit() returns (0x%x).", status);
 

freemodbus/tcp_slave/port/port_tcp_slave.c

@@ -106,8 +106,9 @@ static void* vxMBTCPPortRespQueueRecv(QueueHandle_t xRespQueueHandle)
     BaseType_t xStatus = xQueueReceive(xRespQueueHandle,
                                         (void*)&pvResp,
                                         pdMS_TO_TICKS(MB_TCP_RESP_TIMEOUT_MS));
-    MB_PORT_CHECK((xStatus == pdTRUE), NULL, "Could not get respond confirmation.");
+    if (xStatus != pdTRUE) {
-    MB_PORT_CHECK((pvResp), NULL, "Incorrect response processing.");
+        ESP_LOGD(TAG, "Could not get respond confirmation.");
+    }
     return pvResp;
 }
 
@@ -599,7 +600,7 @@ static void vMBTCPPortServerTask(void *pvParameters)
                                 // Wait while response is not processed by stack by timeout
                                 UCHAR* pucSentBuffer = vxMBTCPPortRespQueueRecv(xConfig.xRespQueueHandle);
                                 if (pucSentBuffer == NULL) {
-                                    ESP_LOGE(TAG, "Response time exceeds configured %d [ms], ignore packet.",
+                                    ESP_LOGD(TAG, "Response is ignored, time exceeds configured %d [ms].",
                                                                         MB_TCP_RESP_TIMEOUT_MS);
                                 } else  {
                                     USHORT usSentTid = MB_TCP_GET_FIELD(pucSentBuffer, MB_TCP_TID);

idf_component.yml

@@ -1,4 +1,4 @@
-version: "1.0.8"
+version: "1.0.9"
 description: ESP-MODBUS is the official Modbus library for Espressif SoCs.
 url: https://github.com/espressif/esp-modbus
 dependencies:

test/tcp/mb_tcp_master/main/tcp_master.c

@@ -73,7 +73,7 @@ static const char *TAG = "MASTER_TEST";
 // Enumeration of modbus device addresses accessed by master device
 // Each address in the table is a index of TCP slave ip address in mb_communication_info_t::tcp_ip_addr table
 enum {
-    MB_DEVICE_ADDR1 = 1, // Slave address 1
+    MB_DEVICE_ADDR1 = 1, // Slave UID = 1
     MB_DEVICE_ADDR2 = 200,
     MB_DEVICE_ADDR3 = 35
 };
@@ -750,7 +750,6 @@ void app_main(void)
     comm_info.ip_netif_ptr = (void*)get_example_netif();
 
     ESP_ERROR_CHECK(master_init(&comm_info));
-    vTaskDelay(50);
 
     master_operation_func(NULL);
     ESP_ERROR_CHECK(master_destroy());

test/tcp/mb_tcp_master/sdkconfig.ci.wifi

@@ -8,6 +8,7 @@ CONFIG_FMB_COMM_MODE_ASCII_EN=n
 CONFIG_FMB_MASTER_TIMEOUT_MS_RESPOND=3000
 CONFIG_FMB_MASTER_DELAY_MS_CONVERT=300
 CONFIG_FMB_TIMER_PORT_ENABLED=y
+CONFIG_FMB_TCP_UID_ENABLED=n
 CONFIG_MB_MDNS_IP_RESOLVER=n
 CONFIG_MB_SLAVE_IP_FROM_STDIN=y
 CONFIG_EXAMPLE_CONNECT_IPV6=n

test/tcp/mb_tcp_master/sdkconfig.defaults

@@ -13,6 +13,7 @@ CONFIG_FMB_MASTER_DELAY_MS_CONVERT=300
 CONFIG_FMB_TIMER_PORT_ENABLED=y
 CONFIG_FMB_TIMER_ISR_IN_IRAM=y
 CONFIG_FMB_TIMER_USE_ISR_DISPATCH_METHOD=y
+CONFIG_FMB_TCP_UID_ENABLED=n
 CONFIG_MB_MDNS_IP_RESOLVER=n
 CONFIG_MB_SLAVE_IP_FROM_STDIN=y
 CONFIG_MB_SLAVE_ADDR=1

test/tcp/mb_tcp_slave/main/Kconfig.projbuild

@@ -2,7 +2,8 @@ menu "Modbus Example Configuration"
 
     config MB_SLAVE_ADDR
         int "Modbus slave address"
-        range 1 255
+        range 1 247 if !FMB_TCP_UID_ENABLED
+        range 0 247 if FMB_TCP_UID_ENABLED
         default 1
         help
             This is the Modbus slave address in the network.

test/tcp/mb_tcp_slave/main/tcp_slave.c

@@ -52,6 +52,8 @@
                                                 | MB_EVENT_COILS_WR)
 #define MB_READ_WRITE_MASK                  (MB_READ_MASK | MB_WRITE_MASK)
 
+#define MB_SLAVE_ADDR (CONFIG_MB_SLAVE_ADDR)
+
 static const char *TAG = "SLAVE_TEST";
 
 static portMUX_TYPE param_lock = portMUX_INITIALIZER_UNLOCKED;
@@ -69,8 +71,6 @@ static portMUX_TYPE param_lock = portMUX_INITIALIZER_UNLOCKED;
 #define MB_DEVICE_ID (uint32_t)CONFIG_FMB_CONTROLLER_SLAVE_ID
 #endif
 
-#define MB_SLAVE_ADDR (CONFIG_MB_SLAVE_ADDR)
-
 #define MB_MDNS_INSTANCE(pref) pref"mb_slave_tcp"
 
 // convert mac from binary format to string
@@ -315,6 +315,7 @@ static esp_err_t slave_init(mb_communication_info_t* comm_info)
 
     comm_info->ip_addr = NULL; // Bind to any address
     comm_info->ip_netif_ptr = (void*)get_example_netif();
+    comm_info->slave_uid = MB_SLAVE_ADDR;
 
     // Setup communication parameters and start stack
     err = mbc_slave_setup((void*)comm_info);
@@ -423,6 +424,7 @@ void app_main(void)
     ESP_ERROR_CHECK(init_services());
 
     // Set UART log level
+
     esp_log_level_set(TAG, ESP_LOG_INFO);
 
     mb_communication_info_t comm_info = { 0 };