Instructions
You can use the open communication through UDP connections for data exchange by way of the Industrial Ethernet CPs of S7-300 and S7-400.

Below we describe how to configure a UDP connection for sending and receiving data by way of an Industrial Ethernet CP of S7-300 and S7-400.

UDP_Connection_en.pdf ( 2150 KB )

The functions below are called in the user program of the CPU for sending and receiving data by way of configured ISO-on-TCP connections.

• FC5 "AG_SEND" and FC6 "AG_RECV" for the S7-300
• FC50 "AG_LSEND" and FC60 "AG_LRECV" for the S7-400

The entries below contain sample programs and instructions for programming the above-mentioned functions in the user programs of S7-300 and S7-400: 17853532 and 18513371.

Note
More information on communication over the Industrial Ethernet with S7-300 and S7-400 is available in the entries below.
 

Entry ID	Description
26484229	What properties, advantages and special features does the UDP protocol offer?
47885440	How do you configure an ISO-on-TCP connection for data exchange between S7-300 and/or S7-400 by way of Industrial Ethernet CPs?
22385024	How do you configure a TCP connection for data exchange between S7-300 and/or S7-400 by way of Industrial Ethernet CPs?
47885244	How do you configure an ISO transport connection for data exchange between S7-300 and/or S7-400 by way of Industrial Ethernet CPs?
29738463	How do you program the communication blocks FB67 "TUSEND", FB68 "TURECV", FB65 "TCON" and FB66 "TDISCON" in order to use the UDP protocol for data exchange by way of the integrated PROFINET interface of a CPU or by way of the CP443-1 Advanced?
30564821	Functions (FC) and Function Blocks (FB) for SIMATIC NET S7 CPs Programming Manual