Alarms-Bacnet; Alarm Classes; Fault Alarms; Problem Alarms - Daikin MicroTech II Installation And Maintenance Manual

Alarm Classes

BACnet alarms in a MicroTech II Chiller Unit Controller are
divided into three classes: Faults, Problems, and Warnings.
Fault alarms have the highest severity level. Problem alarms
have medium severity level. Warning alarms have the lowest
severity level.

BACnet Alarm Handling

The BACnet Communication Module has three methods for
handling BACnet alarms: Alarm Annunciation, Poll Multiple,
and Poll Singular.

Alarm Annunciation

This method of alarm notification sends a BACnet
ConfirmedEventNotification to a single BACnet device
specified in the HTTP interface.
The ConfirmedEventNotification Service includes the following
Fields. See ANSI/ASHRAE 135-2004, BACnet-A Data
Communication Protocol for Building Automation and Control
Networks for detailed definitions.
Not all BACnet devices can receive an alarm message of this
type. A BAS integrator may not want to use this method to
handle alarms. If either case is true, the BAS integrator can
use the Poll Multiple or Poll Singular method.
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Fault Alarms

Fault alarms require an acknowledgment from the operator.
These alarms indicate that the compressor is shut down.

Problem Alarms

Problem alarms do not cause compressor shutdown but limit
operation of the chiller in some way.

Warning Alarms

A warning is enunciated whenever an abnormal condition
exists which does not affect chiller operation.
Table 3: Event Notification Service Details
Field Source
Process Identifier Device Instance Process ID in the HTTP Interface.
Initiating Device Device Instance of the BACnet Communication
Identifier Module as specified in the HTTP Interface.
Object Instance that generated the Alarm. (Subtract
Event Object Identifier 1000 from this value to get the instance of the of the
object in the BACnet Communication Module.)
The time the BACnet Communication Module
Time Stamp
detected the alarm initially.
P = Problems
Notification Class W = Warnings
F = Faults
Priority Priority specified in the HTTP Interface.
Event Type Complex Event.
Message Text Alarm Message Text as shown in Table 4.
Notify Type ALARM
Notification Requirement as shown in the Ack column
AckRequired
of Table 4.
The Event State of the BACnet Communication
From State Module before the occurrence of the event that
caused Alarm.
The Event State of the BACnet Communication
To State Module after the occurrence of the event that caused
the Alarm.
Conditions in the BACnet Communication Module
at the time of the alarm. Each number in the Event
Values column of Table 4 is the instance number of
Event Values
an object in the BACnet Communication Module that
displays its present value in this field of the Event
Notification message.
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