Siemens SIMATIC S7-1500 Function Manual page 278

Order of the OPC UA instructions
The following figure shows the order in which the OPC UA instructions are called in a user
program in order to use these instructions to read or write PLC tags:
①
②
③
Figure 9-71
STEP 7 (TIA Portal) automatically supplies the parameters of these instructions if you are
using a client interface and a configured connection to an OPC UA server.
The procedure is shown in the following section.
Using a client interface and configured connection
To use a configured OPC UA connection, follow these steps:
1. Open your user program in the TIA Portal.
2. Using drag-and-drop, move the "UA_Connect" instruction into the program editor.
You will find the instruction under "Instructions > Communication > OPC UA" in the TIA
Portal.
Communication
Function Manual, 11/2019, A5E03735815-AH
Instructions for preparation of read and write operations
Read and write instructions
Instructions for "clean-up" after a completed read or write operation
The "OPC_UA_NodeReleaseHandleList" instruction can be omitted if "OPC_UA_Disconnect" is
called immediately afterwards.
Call sequence for write and read operations
9.4 Using the S7-1500 CPU as an OPC UA client
OPC UA communication
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