Managing Write And Read Rights For A Complete Db - Siemens SIMATIC ET 200AL System Manual

Write and read rights of structures
If you remove the read or write right for the component of a structure, the structure or the
data block cannot be written or read as a whole.
If you remove read and write rights for individual components of a PLC data type (UDT), the
rights will also be removed from any data block based on that data type!
Visible in HMI engineering
The option "Visible in HMI Engineering" applies to Siemens engineering tools. If you disable
the option "Visible in HMI Engineering" (check mark not set), you can no longer configure the
tag in WinCC (TIA Portal).
The option does not have any effect on OPC UA.
Rules
• Only allow read access to PLC tags and tags of data blocks in STEP 7 if this is necessary for
communication with other systems (controllers, embedded systems or MES).
You should not enable other PLC tags.
• Only allow write access over OPC UA if write rights are genuinely necessary for specific
PLC tags and tags of data blocks.
• If you have reset the "Accessible from HMI/OPC UA" option for all elements of a data block,
the data block for an OPC UA client is no longer visible in the address space of the OPC UA
server of the S7-1500 CPU.
• You can also prevent access to an entire data block centrally (see Managing write and read
rights for a complete DB (Page 209)). This setting "overrules" the settings for the
components in the DB editor.
See also
Coordinating write and read rights for CPU tags (Page 211)
9.3.2.2

Managing write and read rights for a complete DB

Hiding DBs or DB contents for OPC UA clients
You can easily prevent access to a complete data block by an OPC UA client.
With this option, the data of the corresponding DB, including instance DBs of function blocks,
remains hidden for OPC UA clients.
In the default setting, data blocks can be read and written from OPC UA clients. You can
change this default setting in the settings of the TIA Portal: Command "Settings > PLC
programming > General" in "Options" menu. You will find the corresponding option in the
"Default settings for new blocks" area.
Communication
Function Manual, 05/2021, A5E03735815-AJ
OPC UA communication
9.3 Using the S7-1500 as an OPC UA server
209