About external access to public and private data

The

External Access

property setting allows you to specify the level of access (Read Only, Read/Write, or None) external applications and devices have to tags. These external applications and devices include:

RSLinx® Classic

and

FactoryTalk® Linx™

Other Logix controllers

PanelView

PLC/

SLC

controllers

FactoryTalk Historian

3rd party software

The following table describes

External Access

settings:

External Access setting	Description
Read/Write	External applications and devices have full access to the tag and can therefore read and change the tag's value.
Read Only	External applications can read, but cannot change, the tag's value.
None	External Applications cannot read or change the tag's value.

IMPORTANT: The

Logix Designer

application has full access to all tags, regardless of their

External Access

setting.

External access is configured when you create a new tag or data type. After you create a tag, you can modify the tag's

External Access

setting like you would any other tag attribute.

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