Vanguard Security Corporation -
Honeywell Security Products Dealer
PIR Motion Sensors
A passive infrared motion detector (PIR) is an electronic security device that
detects intruders by "sensing" motion or body heat in the area being protected.
Most PIRs are designed to be used when your family is away from home or when
no one will be passing through the area "covered" by the PIR.

Recent innovations in security technology have resulted in the creation of "pet
immune" motion detectors-allowing dog and cat lovers to enjoy the same level of
protection they would receive with a standard PIR. These state-of-the-art sensors
provide "pet immunity" for animals weighing up to 80 lbs. Pet immune PIRs allow
your pet to move about freely but can still detect an intruder’s movement.  

Ademco/Honeywell has alarm detection sensors for wired, wireless and V-Plex

998 Fresnel Lens PIR with Look-Down Zone
Discontinued by Ademco Nov 2006

Replaced with CK-IS2560
  • Horizontal and vertical pattern adjustment
  • Optional swivel mount bracket
  • Alternate polarity pulse count
  • SMD constructions
  • EZ-Mount features for fast trouble free installation
  • Optional coverage patterns (extra lenses included)
  • 6 year over-the-counter warranty
  • Package of six 998 PIRs with look-down available as 998PK
  • Automatic temperature compensation
  • Alarm memory and case tamper (998EX)
  • White light filter
  • High RFI immunity
The ASC Edge:
High Performance Look-Down Design

Positioning of the lens of the look-down zone is critical to look-down
performance. Typically, a PIR will have its look-down lens as an integral part of
the outside housing, as seen on the left side of the figure. This creates two

  • Detection can be compromised. A lens focuses its infrared energy at a
    fixed spot just like a magnifying glass or telescope. For best operation,
    this fixed spot in a motion detector is on the pyroelectric elements.
    When the PCB is moved vertically for coverage adjustment, this energy
    will be defocused except when the board is in just one particular
    position. Less energy is collected and detection performance suffers.

  • Immunity to rodents is compromised. The long focal length (the
    distance from the lens to the pyro elements) causes the projected
    beam for the look-down zone to be small. As seen in the left figure,
    rodents can fill a large portion of the beam and generate a false alarm.

ADEMCO look-down designs overcome both problems by using a shorter focal
length lens mounted very close to the detector as part of the circuit board, as
shown on the right figure. When the PCB is shifted vertically for pattern
coverage adjustment, infrared energy is always focused since the distance
between the lens and the elements never changes. Because the lens is close
to the element, the projected beam on the floor is now large compared to the
size of a rodent. Avoid both detection and false alarm problems with ADEMCO
look-down designs.

Spec Sheet

Copyright 2005
Vanguard Security Corporation
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