UDP_SEND

Type	Function block
Description	The function block is used to send an UDP (Universal Datagram Protocol) datagram to an UDP-capable Ethernet device via an IP socket. The IP socket must first be opened using the UDP_SOCKET function block before data can be sent. Each transmission operation is triggered by a rising edge at the request REQ input. During this cycle, the function block copies the data to be sent (applied to the DATA input) into an internal buffer. The BUSY output is set to TRUE as long as data are being sent from the internal buffer. While BUSY = TRUE, the REQ input is ignored. The transmission of new data that are available at the DATA input during the ongoing transmission cycle can only be triggered with a rising edge at the REQ input once the BUSY output has been set to FALSE. If an error occurs during execution of the function block, the ERROR output is set to TRUE for one cycle. The corresponding error code is provided at the STATUS output within this cycle. The device to which the data are to be sent is specified with the DEST_IP parameter (IP address of the receiving device) and DEST_PORT parameter (port number of the receiving device). WARNING Unintended machine operation Verify that the influence of the output data cannot result in an unintended or hazardous behavior of the entire system.1 1 When running the application logic in simulation mode, the function blocks for Ethernet communication establish a real connection to other devices/servers. Thus, outputs and variables connected to real hardware may be set and therefore may cause real damage to the machine.
Notes	The IP socket opened by the UDP_SOCKET function block can only be used for subsequent calls of the UDP_SEND function block as long as the ACTIVE output of the UDP_SOCKET function block is TRUE. Calling the UDP_SEND function block while ACTIVE = FALSE causes an error at the UDP_SEND function block (ERROR = TRUE and STATUS code = 0xC210 issued). For controllers with integrated firewall, make sure that the firewall does not block the ports involved in the communication. Otherwise, the connection cannot be established. All IP addresses used are IPv4 addresses that consist of four numbers (0 to 255) separated by dot. Function blocks have to be instantiated. The instance name of the function block has to be declared in the 'Variables' table of the POU where the FB is going to be used. The instance name must be unique within the POU.
Parameters	Inputs REQ Data type: BOOL Description: A rising edge at the request REQ input triggers the transmission of the data applied to the DATA input. The input is ignored as long as data are being sent (BUSY = TRUE). All other input parameters are evaluated with a rising edge at the REQ input in case that BUSY = FALSE. HANDLE Data type: DWORD Description: Socket handle that has been opened with the UDP_SOCKET function block (see also the notes above). The parameter is only evaluated in the cycle in which the REQ parameter switches to TRUE. DEST_IP Data type: STRING Description: IP address (IPv4 address) of the device to which the data stored in the DATA buffer are to be sent. The parameter is only evaluated in the cycle in which the REQ parameter switches to TRUE. DEST_PORT Data type: UINT Description: Port number of the device to which the data stored in the DATA buffer are to be sent. The parameter is only evaluated in the cycle in which the REQ parameter switches to TRUE. DATA_CNT Data type: UDINT Description: Number of bytes to be sent from the DATA buffer (DATA_CNT = DATA_CouNT). The maximum number of bytes to be sent is limited to the maximum value of 2147483647 bytes. This limit is only of theoretical nature, in practice the maximum size for the connected variable will be the limiting factor. The parameter is only evaluated in the cycle in which the REQ parameter switches to TRUE. If DATA_CNT = UDINT#16#FFFFFFFF, the whole size of the variable connected to DATA is sent. Tip: You can use the SIZEOF function to determine the size of a variable (number of bytes reserved for the variable in the controller memory). Input/Output DATA Data type: ANY Description: Data buffer which contains the data to be sent to the device identified by the DEST_IP and DEST_PORT parameters. Data is transmitted as byte stream. There is no Little-/Big-Endian conversion. If the data type of the connected variable is a STRUCT (or ARRAY OF STRUCT), the byte stream may contain padding bytes. Outputs DONE Data type: BOOL Description: Set to TRUE once the data has been sent successfully. The output is set for only one cycle. BUSY Data type: BOOL Description: Set to TRUE while the system is trying to send the data. As long as the parameter is set to TRUE, the REQ input is ignored. ERROR Data type: BOOL Description: If an error occurs, the ERROR output is set to TRUE. The corresponding error code can be read at the STATUS output as long as ERROR = TRUE. In case of a detected error, the output is set to TRUE for only one cycle. The error code must be read at the STATUS output within this cycle. See Error Codes / Status Codes for Ethernet FBs. STATUS Data type: WORD Description: Provides the error code in the event of an error (ERROR = TRUE) or the current status of the function block (ERROR = FALSE). Error codes start with 16#Cxxx and status codes with 16#8xxx. See Error Codes / Status Codes for Ethernet FBs.