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DKRCC.PS.RI.A1.02 / 520H4358 - Air Handling Seq. user manual - V 2.2

Produced by Danfoss Electronics spa Graphic Department, 10-2009

Danfoss Electronics spa

Air Handling seq.

- user manual

14| Alarms

14.1| Actions following an alarm

When an alarm occurs, the following actions generally ensue (according to what defined through the Configurator

software “AHU_Interface_vNN.xls”).

The buzzer sounds, if present and if envisaged by the specific alarm

(see “14.3] Alarms table”)

The alarm relay “ALA - Alarm” or the warning “WAR - Warning” is activated depending on what is envisaged

by the specific alarm

(see “14.3] Alarms table”)

The Configurator can be used to define whether the alarm is activated when the unit is OFF.

In the absence of a alarm condition, the Normally Closed (N.C.) and Normally Open

(N.O.) state of the alarm relay is defined when the physical output is configured. If the

polarity is “N.O.” (default setting), the relay is powered in case of an alarm.
The alarm icon is displayed along with the code for the alarm and its description (only for units with LCD

display). For a complete description of the user interface in the case of alarms,

(see “2] User interface”)

14.2| Types of reset

Through the Configurator it is possible to set how the alarms are to be reset: manually, automatically or

semi-automatically.

If reset is manual, a specific procedure is required to resetting them if the alarm

condition doesn’t exists any more: from the menu (Menu: ALA – Alarms, Sub-menu: RAL

– Reset Alarms) to reset all Alarms present or by pressing ENTER from within the alarms

display screen to reset only the currently displayed alarm

(see “2] User interface”)

If reset is automatic, the alarm is deactivated and the signal

disappears as soon as the alarm conditions cease.
If reset is semi-automatic, it means that reset reverts from automatic to manual

after it has occurred a certain (configurable) number of times.

The buzzer is silenced the first time any button is pressed, even if the alarm condition remains in effect; it will remain

silent until a new alarm occurs.

14.3| Alarms table

Each alarm is characterized by:

code: ID tag that unequivocally identifies the alarm and which is displayed on the screen;
description: displayed only on LCD displays;
source of the alarm;
type of reset: (-1=automatic, 0=manual, >0=number of occurrences for semi-automatic alarms);;
if semi-automatic alarms, the period for counting alarm occurrences; if during this time the

alarm exceeds its maximum number of occurrences, it becomes a manual reset alarm;
delays for detecting the alarm after start-up and when in steady operation;
whether it is active even when the machine is in standby mode;
how it affects the alarm relay, warning and buzzer;
how it affects the unit actuators

as described in the table below.
The columns in grey contain data that can be modified with the Configurator software

ALARMS TABLE

Code Description

Source

Type of

reset

Semi

automatic

period

(min)

Delay

start-