Page 64
Sonic-Pro
Industries, Ltd.
Industries, Ltd.
ProSeries
by Blue-White Ind.
TM
8.3.4
More on
Alarm
Conditions
This section contains additional explanation of the conditions under which an alarm
condition is cleared.
The flowmeter will clear an alarm condition automatically if and only if a
Release
value
has been set for the
Trigger
value that caused the alarm. For example, if the alarm was
caused by the flow rate falling below the
Low Trigger
, then the alarm will be
automatically cleared if a
Low Release
has been set. Whether or not a
High Release
is
set in this case is of no consequence. If a
Release
value has not been set, the alarm is
said to be “latched”. A latched alarm can only be cleared if the user presses the
CLEAR
soft button and the flow rate has fallen back inside the
Trigger
values.
The effect of setting an
Alarm Delay Time
is to add states in which an alarm condition
exists but the relay is temporarily not energized. During these states, the alarm
condition may clear and the relay will then remain de-energized. These states end when
the
Alarm Delay Time
elapses and if at that time the alarm condition has not cleared
then the relay will energize.
The four combinations of a set
Release
value (for the alarming Trigger value) and an
Alarm Delay Time
are as follows:
?
No
Release
value, no
Alarm Delay Time -
the alarm is latched and can only be
cleared by the user pressing the
CLEAR
soft button when the flow rate has fallen
inside the
Trigger
value.
!
Release
value, but no
Alarm Delay Time -
alarm clears automatically as soon as
the flow rate falls inside the
Trigger
value (the
CLEAR
soft button serves no
purpose).
!
No
Release
value, an
Alarm Delay Time
is set
-
the alarm is latched (will never
clear automatically) and must be cleared by the user pressing the
CLEAR
soft
button, however, as well as clearing on the press if the flow is inside the
Trigger
value, it will also clear if the flow falls inside the
Trigger
value while the
Alarm
Delay Time
is being counted down (the channel is in the
CLEARING
state).
!
Release
value and an
Alarm Delay Time -
the alarm clears whenever the flow
rate falls inside the
Trigger
value and the purpose of the
CLEAR
soft button is
only to temporarily de-energize the relay.
