3.3 Data Transfer

The DataTransfer message in OCPP 1.6J allows the charge point and central system to exchange custom data. It includes a VendorId, MessageId and data payload, enabling proprietary or vendor-specific information to be sent. The central system responds with an acknowledgment, or an error if the data is invalid.


API Syntax	Description	Input Params	Return Value
OCPPDataTransferResetGlobals	Function to reset global variables for Data Transfer.	void	void

Example:

void OCPPResetAllGlobals(void) 
{
    UtilitiesGlobalVariablesReset();
    UtilitiesLocalStorageResetGlobals();
    OCPPSetChargingProfileResetGlobals();
    OCPPGetCompositeScheduleResetGlobals();
…………..
    OCPPGetConfigurationResetGlobals();
    OCPPDataTransferResetGlobals();
    OCPPClearCacheResetGlobals();
    OCPPChangeConfigurationResetGlobals();
    OCPPChangeAvailabilityResetGlobals();
    OCPPBootNotificationResetGlobals();


API Syntax	Description	Input Params	Return Value
SendDataTransferRequest	This function creates and sends a Data Transfer request frame to the server. It handles the creation of the OCPP frame and manages the transmission state.	(void)	void

Example:

          		
if (result != 1)
{
LogDebug("APP_LOG", "Error reading data\n");
}
SetDataTransferRequestData(data);
SendDataTransferRequest();
return result;


API Syntax	Description	Input Params	Return Value
SetDataTransferRequestData	Sets the data field of the Data Transfer request.	char *data	void

Example:

    if (result != 1)
    {
        LogDebug("APP_LOG", "Error reading data\n");
    }
    SetDataTransferRequestData(data);
    SendDataTransferRequest();

    return result;


API Syntax	Description	Input Params	Return Value
SetDataTransferRequestMessageId	Sets the messageId field of the Data Transfer request.	char *messageId	void

Example:

	if (result != 1) 
                    {
                        LogDebug("APP_LOG", "Error reading messageId\n");
                    }
                    SetDataTransferRequestMessageId(messageId);
                    LogDebug("APP_LOG", "Enter the Data : ");
                    result = scanf("%1023s", data);
                    if (result != 1) 
                    {
                        LogDebug("APP_LOG", "Error reading data\n");
                    }
                    SetDataTransferRequestData(data);
                    SendDataTransferRequest();
return result;
                }


API Syntax	Description	Input Params	Return Value
SetDataTransferResponseStatus	Sets the status of the Data Transfer response.	DATA_TRANSFER_STATUS_T Status	void

Example:

      if (strncmp(DataTransferParms.vendorId, TESTING_VENDOR_ID, VENDOR_ID_MAX_LEN) == 0)
      {
        LogDebug("APP_LOG", " DataTransfer CSMS send Unknown VedorId\n\r");
        SetDataTransferResponseStatus(DATA_TRANSFER_UNKNOWN_VENDOR_ID);
      }
      else if (strncmp(DataTransferParms.messageId, TESTING_MESSAGE_ID, MESSAGE_ID_MAX_LEN) == 0)
      {
        LogDebug("APP_LOG", " DataTransfer CSMS send Unknown MessageId\n\r");
        SetDataTransferResponseStatus(DATA_TRANSFER_UNKNOWN_MESSAGE_ID);
      }
      else if (strncmp(DataTransferParms.data, TESTING_DATA, DATA_MAX_LEN) == 0)
      {
        LogDebug("APP_LOG", " DataTransfer CSMS send Unknown message\n\r");
        SetDataTransferResponseStatus(DATA_TRANSFER_REJECTED);
      }
      else
      {
        SetDataTransferResponseStatus(DATA_TRANSFER_ACCEPTED);
      }
    }


API Syntax	Description	Input Params	Return Value
SetDataTransferResponseData	Sets the data field of the Data Transfer response.	char *data	void

Example:			if((DATA_TRANSFER_INITIATOR)responsecode==DATA_TRANSFER_INITIATOR_CSMS)
{
SetDataTransferResponseData(GetDataTransferRequestData());
LogDebug("APP_LOG", " DataTransfer Params Request: vendorId: %s messageId: %s data: %s\n\r", GetDataTransferRequestVendorId(), GetDataTransferRequestMessageId(), GetDataTransferRequestData());


API Syntax	Description	Input Params	Return Value
DataTransferInit()	This function initializes the Data Transfer request and response structures with default values.	void	void

Example:

void OCPPMessagesInit(void)
{
    DataTransferInit();
    ResetInit();
    MeterValueStructInit();
    SetLocalListVersionNumber(DEFAULT_SEND_LOCAL_LIST_VERSION);   
    SetChargePointConnectorId(CHARGEPOINT_DEFAULT_CONTROLLER);
    ChargePointStatusInit();
    (void)SetAuthorizeStatus(AUTHORIZE_INVALID);
    SetOCPPWebsocketOnlineMode();
    UnlockConnectorInit();
    ReserveNowInit();
    ChangeAvailabilityInit();
    ClearCacheInit();
    ChangeConfigurationInit();
    CancelReservationInit();
    GetAllIDsFromDB();
    CheckAndStartClockAlignedMeterValueTimer();
    ClearChargingProfileInit();
    GetCompositeScheduleInit();
    GetLocalListVersionInit();
    SendLocalListInit();
    TriggerMessageInit();
    RemoteStopTransactionInit();
    RemoteStartTransactionInit();
}


API Syntax	Description	Input Params	Return Value
SetDataTransferRequestVendorId	Sets the VendorId field of the Data Transfer request.	char *vendorID	void

Example:

int TestDataTransfer(void)
{
    char vendorId[VENDOR_ID_MAX_LEN];   /* Vendor ID associated with the Data Transfer request. */
    char messageId[MESSAGE_ID_MAX_LEN]; /* Message ID for the Data Transfer request. */
    char data[DATA_MAX_LEN];            /* Data to be transferred. */
    LogDebug("APP_LOG", "Enter the Vendor ID : ");
    int result = scanf("%254s", vendorId);
    if (result != 1)
    {
        LogDebug("APP_LOG", "Error reading vendorId\n");
    }
    SetDataTransferRequestVendorId(vendorId);

    LogDebug("APP_LOG", "Enter the Message ID : ");
    result = scanf("%49s", messageId);


API Syntax	Description	Input Params	Return Value
GetDataTransferStatusType	This function returns the status of the DataTransfer.	DATA_TRANSFER_STATUS_T status	char

Example:

else if ((DATA_TRANSFER_INITIATOR)responsecode == DATA_TRANSFER_INITIATOR_CHARGE_STATION)
{
RX_DATATRANSFER_RESPONSE_T DataTransferParms;
GetDataTransferRequestParmsTX(&DataTransferParms);
LogDebug("APP_LOG", " DataTransfer Response Params: statusENUM: %d status: %s hasData: %d data: %s\n\r", DataTransferParms.status, GetDataTransferStatusType(DataTransferParms.status), DataTransferParms.hasData, DataTransferParms.data);
}


API Syntax	Description	Input Params	Return Value
GetDataTransferRequestData	This function returns the data of the DataTransfer.	void	char

Example:

else if(strncmp(GetDataTransferRequestData(),
TESTING_DATA, DATA_MAX_LEN) == 0)
{
LogDebug("APP_LOG", " DataTransfer CSMS send Unknown message\n\r");
SetDataTransferResponseStatus(DATA_TRANSFER_REJECTED);
}


API Syntax	Description	Input Params	Return Value
GetDataTransferRequestMessageId	This function returns the MessageId of the DataTransfer.	void	char

Example:


else if (strncmp(GetDataTransferRequestMessageId(), TESTING_MESSAGE_ID, MESSAGE_ID_MAX_LEN) == 0)
{
LogDebug("APP_LOG", " DataTransfer CSMS send Unknown MessageId\n\r");
SetDataTransferResponseStatus(DATA_TRANSFER_UNKNOWN_MESSAGE_ID);
}


API Syntax	Description	Input Params	Return Value
GetDataTransferRequestVendorId	This function returns the VendorId of the DataTransfer.	void	char

Example:

if (strncmp(GetDataTransferRequestVendorId(), TESTING_VENDOR_ID, VENDOR_ID_MAX_LEN) == 0)
{
LogDebug("APP_LOG", " DataTransfer CSMS send Unknown VedorId\n\r");
SetDataTransferResponseStatus(DATA_TRANSFER_UNKNOWN_VENDOR_ID);
}


Syntax	Description	Constants/Members
TX_DATATRANSFER_RESPONSE_T	This structure contains the fields for a Data Transfer response to be sent to the central system.	`DATA_TRANSFER_STATUS_T status;` `int hasData;` `char data[];`
RX_DATATRANSFER_REQUEST_T	This structure contains the fields required for a Data Transfer request from the central system.	`char uuid[];` `char vendorId[];` `char messageId[]` `int hasData;` `char data[];`
TX_DATATRANSFER_REQUEST_T	This structure contains the fields required for a Data Transfer request from the Charge Station.	`char vendorId[];` `int hasMessageId;` `char messageId[];` `int hasData;` `char data[]`
RX_DATATRANSFER_RESPONSE_T	This structure contains the fields for a Data Transfer response received from the central system.	`DATA_TRANSFER_STATUS_T status;` `int hasData;` `char data[];`
DATA_TRANSFER_INITIATOR	Enum represents the possible initiators of a Data Transfer operation.	DATA_TRANSFER_INITIATOR_CSMS DATA_TRANSFER_INITIATOR_CHARGE_STATION DATA_TRANSFER_INITIATOR_CSMS_REQUEST_ERROR DATA_TRANSFER_INITIATOR_CHARGE_STATION_RESPONSE_ERROR
DATA_TRANSFER_STATUS_T	Enum represents the possible statuses of a Data Transfer operation.	DATA_TRANSFER_ACCEPTED DATA_TRANSFER_REJECTED DATA_TRANSFER_UNKNOWN_MESSAGE_ID DATA_TRANSFER_UNKNOWN_VENDOR_ID