Siemens Simatic S7-400 - Page 80

Programming the OPC UA client blocks
5.1 Program blocks for the OPC UA client
CP 443-1 OPC UA
80 Operating Instructions, 01/2017, C79000-G8976-C427-02
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FB234 UA_Disconnect
Terminates the connection of a current session with an OPC UA server.
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FB235 UA_ReadList
Using the list of node handles, reads the data from nodes of the connected server.
– UDT754 UANodeAdditionalInfo
Specifies the item attribute and the index range for the block parameter
"NodeAddInfos".
– UDT755 UAIndexRange
Specifies the start and end index for the block parameter "IndexRange”.
– UDT756 UATimeStamps
Contains the time stamps of the elements of the data area of the block parameter
“Variables”.
– UDT757 UAAnyPointer
References the memory area of the CPU in which the process data for the block
parameter “Variables” will be stored.
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FB236 UA_WriteList
Using the list of node handles, writes data to nodes of the connected server.
– UDT754 UANodeAdditionalInfo
Specifies the item attribute and the index range for the block parameter
"NodeAddInfos".
– UDT755 UAIndexRange
Specifies the start and end index for the block parameter "IndexRange”.
– UDT757 UAAnyPointer
References the memory area of the CPU in which the process data for the block
parameter “Variables” is stored.
Additionally required system functions SFC
For the full functionality of the program blocks for the OPC UA client the following system
functions are required:
● BLKMOV / SFC20
● TIME_TCK / SFC64
For its function, UA_Connect also requires:
● LGC_GADR / SFC49
● RDSYSST / SFC51
Creating the SFCs in STEP 7 V5
In addition to the required program block copy the SFCs from the standard block library to
the block container of the CPU and supply the parameters of the SFCs.