Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 66)

F ACTORY T ALK V IEW S ITE E DITION U SER ’ S G UIDE
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For details, see “Working with Tag Alarm and Event Servers” on page 12-21, and “Setting
up FactoryTalk tag-based alarms” on page 12-23.
Traditional HMI tag alarms
In a FactoryTalk View SE application, you can also set up alarms for tags in a FactoryTalk
View SE Server’s tag database. These alarms are called HMI tag alarms.
If your application uses HMI tags for other purposes, and you want to monitor these tags
for alarms, use a traditional HMI alarm system.
FactoryTalk View SE Clients receive HMI tag alarm information, by way of the HMI
servers where the HMI tags reside.
HMI tag alarm information is not distributed by FactoryTalk Alarms and Events services.
This means that you cannot monitor and interact with HMI tag alarms, using FactoryTalk
alarm displays and logs.
For more information about HMI tag alarm monitoring, see Chapter 11, Setting up HMI
tag alarms.
Deciding when to use HMI tags
Use HMI tags in an application to provide extended capabilities, such as:
 Triggering an alarm when the value of an HMI tag crosses a specified threshold.
 Scaling or offsetting a value before sending it to a programmable controller or device.
 Security features that prevent unauthorized changes to a tag’s value.
 Flexible addressing. HMI tags do not require hard-coded physical addresses or
device-specific variable names. This means you can re-use an application with other
devices, simply by changing the physical addresses the tag names are mapped to.
 Descriptive tag names, which you cannot create in some controllers or OPC servers.
For more information about HMI tags, see “Working with tags” on page 10-1.
Designing the HMI tag database
Before creating an HMI tag database, take the time to plan it. A good design helps reduce
the maintenance time, and can improve device-to-FactoryTalk View response time.
Collect the following information:
 Process flowcharts (or process and instrument diagrams)
 A list of programmable controller data table or register addresses for the application