Rockwell Automation FactoryTalk View Machine Edition Users Guide - Manual (Page 138)

F ACTORY T ALK V IEW M ACHINE E DITION U SER ’ S G UIDE
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You can also assign connections to alarm lists, to allow the data source to determine which
types of alarms to show in the lists. For more information, see page 9-32.
Connections that work with a specific alarm trigger
You can assign a different set of these connections to each alarm trigger, or to only one or
some alarm triggers:
 Handshake—Assign a tag to this connection to notify the data source when the
trigger’s value changes.
 Ack—Assign a tag to this connection to notify the data source when the operator
acknowledges an alarm (or all alarms).
 Remote Ack—Assign a tag or an expression to this connection to allow the data
source to acknowledge alarms.
 Remote Ack Handshake—Assign a tag to this connection to notify the data source
when a remote acknowledgement occurs.
 Message—Assign a tag to this connection to send alarm messages to the connection.
Make sure the tag supports the type of data sent in the alarm message. For example, if
the message is a string of text, assign a string tag to the Message connection.
 Message Notification—Assign a tag to this connection to notify FactoryTalk View
that an alarm message has been sent to the connection and FactoryTalk View must
wait before sending a new message.
 Message Handshake—Assign a tag to this connection if you want the data source to
notify FactoryTalk View when it has read the message.
Assign tags or expressions to these connections when you create your alarm triggers. For
more detailed information about how these connections work, see the next sections.
How the Handshake connection works
The Handshake connection is useful for triggers that use the Value data type. Program the
data source to queue alarm notifications when multiple alarms are generated for the same
trigger. Use the Handshake connection to notify the data source that FactoryTalk View has
detected the alarm notification. Then the data source can send the next alarm to
FactoryTalk View.
When the application starts, the Handshake connection has a value of 1. When the trigger
connection’s value changes, the Handshake connection’s value toggles from 1 to 0. The
next time the trigger value changes, the Handshake connection’s value toggles from 0
to 1.