Siemens SIMATIC S7 System Manual page 518

Libraries
9.4 Open user communication library
Note that UDP messages are not guaranteed to be delivered. There is no error returned if
the remote device is not present.
Table 9- 19
Parameter
EN
Req
ConnID
DataLen
DataPtr
IPaddr1
...
IPaddr4
RemPort
Done
Busy
Error
Status
518
Parameters of the UDP_SEND instruction
Declaration Data type
IN BOOL
IN BOOL
IN WORD
IN WORD
IN DWORD
IN BYTE
IN WORD
OUT BOOL
OUT BOOL
OUT BOOL
OUT BYTE
Description
Enable input
The CPU starts the send operation if Req =
TRUE. If Req = FALSE, then the outputs show
the current status of the send operation.
The Connection ID (ConnID) is the number of the
connection for this send operation (defined during
the connect process with UDP_CONNECT).
The DataLen is the number of bytes to transmit (1
to 1024).
The DataPtr is the pointer to the data to be sent.
This is an S7-200 SMART pointer to I, Q, M, or V
memory (for example, &VB100).
These are the four IP address octets. IPaddr1 is
the most significant byte and IPaddr4 is the least
significant byte of the IP address.
The RemPort is the port number on the remote
device. The remote port number range is 1 to
49151.
The instruction sets the Done output when the
connect operation is complete with no errors.
The instruction sets the Busy output while the
connection operation is in progress.
The instruction sets the Error output when the
connection operation is complete with an error.
Refer to "Open user communication library in-
struction error codes" (Page 524) for further in-
formation.
The Status output shows the error code if the
instruction sets the Error output. Status is zero
(no error) if the instruction sets the Busy or Done
outputs.
System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART