UDP does not guarantee that messages will arrive, come in the right order, or not get repeated. It is normal to lose some packets, especially if you send them quickly or the network is busy. If you set the sample time for the UDP Receive block too high, you might miss packets because the buffer fills up. If it is too low, you could be checking too often, which is not efficient. Network issues like congestion, switches, or firewalls can also cause delays or lost packets.
Here are some troubleshooting steps which might help resolve the issue:
- Lower the sample time a bit more. Also, try increasing the buffer size in the UDP Receive block to handle more data at once.
- Test your setup with a direct Ethernet cable, without any switches or routers in between. Use a tool like Wireshark to see if packets are being lost.
- Ensure the PLC and Simulink are synchronized in terms of send/receive timing. For example, if the PLC sends data every 100 ms, set Simulink’s step size to 100 ms too. You might also want to add a small pause on the PLC after each packet is sent.
- Double-check your MATLAB Function block that looks for headers. Make sure it is not skipping valid packets because of parsing mistakes.
Hope this helps!
