Receive UDP packet
The UDP Receive block receives UDP packets from an IP network port and saves them to its buffer. With each sample, the block outputs the contents of a single UDP packet as a data vector.
Message— Received messages
The UDP Receive block outputs the received UDP packets
as an N-by-1 data vector. The
Data type for Message
Length parameters set the vector data type and
message length, N, respectively.
This port is unnamed while
signal is enabled.
Length— Length of the Message vector
This port outputs the length of the message vector signal on port
This port is hidden while
signal is enabled.
Local IP port— Local IP port
25000(default) | 1 – 65535
Enter the IP port number on your hardware board that receives UDP data packets.
On Linux®, to set the IP port number below 1024, run MATLAB® with root privileges. For example, at the Linux command line, enter:
Remote IP address— Remote IP address
'0.0.0.0'(default) | character vector
Enter the IP address from which to accept packets. Entering a specific IP
address blocks UDP packets from other addresses. To accept packets from any
IP address, enter
Receive buffer size (bytes)— Receive buffer size
Make the receive buffer large enough to avoid data loss caused by buffer overflows.
Maximum length for Message— Maximum length for Message
Enter the maximum length, in vector elements, of the data output vector. Set this parameter to a value equal or greater than the data size of a UDP packet. The system truncates data that exceeds this length.
If you disable Output variable-size signal, the block outputs a fixed-length output the same length as the Maximum length for Message.
Data type for Message— Data type for Message
Set the data type of the vector elements in the Message output. Match the data type with the data input used to create the UDP packets.
Output variable-size signal— Output variable-size signal
To support signals of varying length in your model, select this parameter. To support fixed-length signals, clear this parameter. When you clear this parameter, the block:
Emits the data vector of fixed-length, set by the Maximum length for Message, from the Message output.
Emits the length of the valid data from the Length output.
If the UDP packet contains less data than the fixed-length output, the difference contains invalid data.
In both cases, the block truncates data that exceeds the Maximum length for Message.
Blocking time (seconds)— Time to wait for UDP packet
For each sample, wait this length of time for a UDP packet before
returning control to the scheduler. This value defaults to
inf, which indicates to wait indefinitely.
Sample time (seconds)— Sample time
Enter how often the scheduler runs this block. Enter a value greater than zero. In real-time operation, setting this option to a large value reduces the likelihood of dropped UDP messages.