Panasonic Eco Solutions Nordic AB
MEW01622
Rev: -
EBL128 Planning Instructions V2.0.x
95
Figure 19. An
example
of the filtering algorithm for an Analog
smoke detector with the step value X = 5. The polling time (t) in
this
example is approx. 2.56 seconds.
Explanations to the figure:
In this example, the week average sensor value is "10" (=1.0 %/m) at
the "starting point", i.e. due to contamination the pre-warning level
has been adjusted to "32" (10+22) and the fire alarm level to "40"
(10+30). The sensor value is accordingly "10".
In this example, alarm algorithm "N-15" is selected, i.e. normal
detection time 15 sec. and normal sensitivity 3% (30). X = 5. The
detector polling time
t
≈ 2.56 sec. (
In system EBL128
the detector
polling time
t
≈ 7 seconds and the step value "X" is according to
Figure 18 – but the
principle
is the same.)
In this example, the sensor values and decision values at start are
approx. equal ("10"). When smoke comes into the detector the sensor
values will increase and by the fourth polling be approx. "27". Since
27-10 > X=5, the decision value ("10") is increased by X=5 to "15".
Next polling the sensor value is approx. "45", i.e. the decision value
("15") is increased by X=5 to "20", and so on. In this example the
decision value never comes up to the fire alarm level. When the
sensor value is reduced to approx. "25" the decision value is set to
"30", because 35-25=10 > X=5, i.e. the decision value ("35") is
reduced by X=5 to "30", and so on.
1.
The sensor value has here reached the pre-warning level but
nothing will happen since the decision value has not reached the
pre-warning level.
2.
The sensor value has here reached the fire alarm level but nothing
will happen since the decision value has not reached the fire alarm
level.