Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 352)

F ACTORY T ALK V IEW S ITE E DITION U SER ’ S G UIDE
14–8
• •
•
•
•
What happens if the Network Directory server is unavailable
The Network Directory server cannot be made redundant. Instead, if the Network
Directory becomes unavailable while client computers are connected to an application,
the clients continue to run, using a local cache of directory information.
There is no need to restart previously connected clients; they will continue to resolve tag
addresses, read and write tag values, acknowledge alarms, and open graphic displays,
even if the tags and displays the clients require were never used before.
While the Network Directory is unavailable, you cannot modify the structure of any
dependent application.
For example, you cannot add areas or servers to the application, create new security
accounts, or change system security policies.
When the Network Directory is available again, all dependent clients in the system
resume using the directory automatically.
Redundancy as part of a system availability strategy
The more protection you provide, the more dependable the entire control system will be,
in the event any hardware or software component fails.
The level of system availability increases with the number of redundant system
components. To protect against:
 Programmable controller failures, make programmable controllers redundant.
For example, you can set up redundancy for Rockwell Automation Logix5000
controllers.
 Programmable controller network failures, install redundant programmable
controller networks, such as a Rockwell Automation’s ControlNet network.
 Information network failures, install a redundant Ethernet network with a backup
domain controller, network cables, and network interface cards.
The status of this
Network Directory
server is (connected).