cias PYTHAGORAS2 Series, Installation Manual, Page: 59 / 76

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CIAS Elettronica S.r.l. Ed. 1.1
Installation Manual Page 58 of 70 PYTHAGORAS 2
4 The masking thresholds are positioned one above and one below the field signal level
memorised during the working parameter a
cquisition phase (SW1 in Position 2 phase “j”).
They verify if there is a variation in the received field that could alter the detection capability
of the barrier. These variations can be created, for example, by progressive accumulation
of snow along the protected area or they could be produced deliberately in an attempt to
overcome the protection. The sensitivity to the detection of these variations is set during
manufacture to the
default value of “2”
, using switch SW4 . To reduce this sensitivity move
SW1 to position 3 and set SW4 to a lower value, such as:
“1”, “0” and press S1
. NB.
Setting the value to “0” effectively disables this function. If an increase in sensitivity is
required move SW1 to position 3 and set SW4 to a higher value, such as:
“3”, “4”, “5”,
“6”, “7”, “8”, “9”, “A”, “B”, “C”, “D”, “E”, “F” an press S1.
NB. Setting this value too
high will create more possibilities of false alarms from the MW barrier.
5
After completing the IR alignment phase (described in the next section) it is possible to
select the operating scenario most suitable to the requirements of the site to be protected.
The choice of scenario is made using switch SW1 and selecting one of the following
positions:
“9”, “A”, “B”, “C”, “D”, “E”, “F”, “0”.
The scenarios are as follows:
Scenario “0” : AND with 2 techno priority Filters
Selecting this option will produce an alarm only if at least one pair of barriers of different
technologies reach alarm with the following sequence: first MW or Doppler and then IR.
MW and then Low IR, or Middle IR, or High IR, or disqualification Alarm
Doppler and then Low IR, or Middle IR, or High IR, or disqualification Alarm
Disqualification and then MW, or Doppler, Alarm
IR Low and then MW, or Doppler, or Middle IR, or High IR, or disqualification No Alarm
IR Middle and then MW, or Doppler, or Low IR, or High IR, or disqualification No Alarm
IR High and then MW, or Doppler, or Low IR, or Middle IR, or disqualification No Alarm
MW and then Doppler No Alarm
Doppler and then MW No Alarm
The use of this scenario allows to reduce drastically false alarms due to the reaction of the
different technologies used in critical environmental conditions, such as heavy fogs or rain,
narrow corridors and closed and loosen fences. The consequent reduction in probability of
detection must be always evaluated for the specific site requirements.
Note: middle IR is optional.
Scenario “9” : AND with 2 technologies Filter
Selecting this scenario will produce an alarm if at least two of barriers of different technologies,
regardless to the sequence (priority), detect an alarm condition.
MW and then Low IR, or Middle IR, or High IR, or disqualification Alarm
Doppler and then Low IR, or Middle IR, or High IR, or disqualification Alarm
IR Low and then MW, or Doppler Alarm
IR Middle and then MW, or Doppler Alarm
IR High and then MW, or Doppler Alarm
Disqualification and then MW, or Doppler, Alarm
MW and then Doppler No Alarm
Doppler and then MW No Alarm
IR (Low, Middle, High) and then Low IR, or Middle IR, or High IR No Alarm
This scenario will filter alarms created by the IR barriers when, for example, two of them, just
before to go into disqualification, produce the alarm condition.