Flowserve MX HART Field Unit - Manual (Page 36)

MX/QX HART Field Unit FCD LMENIM2340-00 – 1/14
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Figure 3.5 – Trigger Mode 1 “Windowed”
Even if the value does not deviate beyond the window, a Burst Message will be published when the max update period
is exceeded.
In Rising Mode, the Burst Message is published when the source value exceeds the trigger value. Burst Messages are
published at the rate indicated by the update period, as long as the source value remains above the trigger value. If the
value falls below the trigger value, the update time will drop to the maximum update period.
In Falling Mode, the Burst Message is published when the source value drops below the trigger value. Burst Messages
are published at the rate indicated by the update period, as long as the source value remains below the trigger value. If
the value exceeds the trigger value, the update time will drop to the maximum update period.
In the On-Change Mode, the Burst Message is published when the value in the message changes. If the value does not
change, the Burst Message will be published at the maximum update period.
3.5.4 Event Notification
Event Notification requires Burst Mode operation; therefore, at least one burst message must be enabled for event
notification to occur. The HART protocol provides two distinct methods for displaying events:
• Field Device Status
• Command 48 response
Event Notification publishes changes in the device’s status, independently from other data published in other Burst
Messages. Bits from the Field Device Status and the command 48 response data may be selected using a bit mask to
send Event Notifications. This allows the Event Notification to be limited to specific bits.
The device shall retain Event Notification Settings through a device reset, self-test or power-cycle. However, Event
Notification and Time Stamps are not maintained through power cycles or a device reset. The MX/QX HART device
supports an event history queue of five events for the configured Event Notification. If more events are detected than
can be buffered, then the “Event Notification Overflow” bit in Standardized Status 1 (see section 3.5.1.1 Command 48
Data) shall be set until all pending events have been acknowledged. Events detected after the event queue is full are lost.
3.5.4.1 Configuring Event Notification
Event Notification can be configured from the DD menu Device Setup->Wired Hart Board->Configuration->
Event Notification as follows: