SIDirect absolute naming convention
- Last UpdatedJul 29, 2024
- 1 minute read
The SIDirect Legacy interface included with the SIDirect Communication Driver supports only "traditional" absolute addressing of PLC items. To use absolute addressing:
-
Optimized Block Access must be disabled (non-optimized mode).
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GET/PUT must be enabled.
Note: Symbolic addressing is only supported through the S7_1500_Plus interface.
In general, the item syntax takes the following format:
D[DataBlock#],[DataTypePrefix][OffsetAddress]<.BitAddress>,<ArraySize><DataDisplayFormatSuffix>
Example:
|
DB10,INT2,8 |
Data Block #10 Integer array item of 8 elements starting at 2 bytes offset |
|
DB25,DWORD4BCD |
Data Block #25 Double Word item shown in BCD starting at 4 bytes offset |
Note: The common “D” data block identifier above maybe replaced by a prefix letter such as F (Flag), M (Memory), I (Input), Q (Output), PI (Peripheral Input), PQ (Peripheral Output), T (Timer), C (Counter) for register items from various special Areas in the S7 PLC program.