Siemens Simatic S7-400

Programming the OPC UA client blocks
5.8 FB235 UA_ReadList
CP 443-1 OPC UA
96 Operating Instructions, 01/2017, C79000-G8976-C427-02
You program the attributes to be read in a UDT "UANodeAdditionalInfo" that is referenced by
the input parameter "NodeAddInfos".
The handles required at the input parameter "NodeHdls" are read from array of the output
parameter "NodeHdls" of the "UA_NodeGetHandleList" block.
The number of nodeIDs at the input parameter "NodeIDCount" is always 1 so you need to
call the block separately for each target node.
Call interface
Figure 5-7 Call interface in FBD representation
5.8.2
Parameter - UA_ReadList
Block parameters
The following table explains the formal parameters of the program block.
Table 5- 9 Parameters of the block UA_ReadList
Parameter
Declaration
S7 data type
Range of values
Meaning
Execute IN BOOL 0, 1 A rising edge 0 → 1 at the parameter starts
processing of the block.
ConnectionHdl
IN
DWORD
1 .. 5
Connection identifier supplied by UA_Connect
NodeHdlCount IN WORD 1 Number of elements in the target area to be
read. The number of must be 1.
NodeHdls IN ARRAY of
DWORD
1 Array of the handles of the target nodes (items)
of the OPC UA server. The handles are read
from array of the output parameter "NodeHdls"
of the "UA_NodeGetHandleList" block.
NodeAddInfos IN ARRAY of
UDT
See “Meaning” Specifies the attribute of the items to be read
and the index range. For information on the
structure of the UDT, see UDT754
UANodeAdditionalInfo (Page 98).