De Nora Capital Controls CHLORALERT 17CA3000 Series - Delay; Figure 3-3 Self-Resetting Alarm Operation; Figure 3-4 Latching Alarm Operation

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Latched Alarms (non-self resetting):
Figure 3-4 shows the behavior of a latched alarm. Alarm operation is similar to the self-
resetting alarm except that the alarm will remain active until the operator acknowledges
the alarm by pressing the ACK key on the keypad, represented by time t3 in Figure 3-4.
A latched alarm condition can only be successfully reset after the sensed gas concentration
has fallen below the alarm threshold, indicating by time t2 in Figure 3-4. Any attempt
to acknowledge the alarm before time t2 will be ignored by the instrument and the alarm
condition will remain active.
When the ACK key is pressed, the instrument polls all latched alarms. Those whose levels
have fallen below the alarm threshold are cleared while the other remains active. The alarms
are polled only once each time the ACK key is pressed.
Figure 3-4 Latching Alarm Operation
3.2.2.14.4 Delay
If desired, an alarm-delay time may be entered. The DELAY menu selection enables
entering a value, in seconds, up to a maximum of 255 seconds. A delayed alarm will not
be signaled until the sensed gas concentration exceeds the threshold continuously for the
duration of the alarm-delay time.
Figure 3-3 Self-Resetting Alarm Operation
GAS CONCENTRATION
ALARM LEVEL
TIME
t1 t2
ALARM DURATION
ALARM ENDS
GAS CONCENTRATION
TIME
ALARM LEVEL
ALARM DURATION
t1
t2
t3
ALARM CONDITION ENDS
"ACK"
key
is pressed