Class1 119327 - VDR system 118093 118097 118551 118620 119375 - EXTERNAL - Manual (Page 10)

FORM-ENG-0018 REV A 05-27-03
607 NW 27th Ave
Ocala, FL 34475
Ph: 352-629-5020 or 1-800-533-3569
Fax : 352-629-290 or 1-800-520-3473
PRODUCT MANUAL
PAGE 9 OF 26
DATE 10/17/2011
PRODUCT GROUP ES-Key P/N 119914, 118093, 118620, 118551, 119375 REV 1.70
PRODUCT Vehicle Data Recorder and Seat Belt Warning system BY AMS
5. Operation
5.1. Seat and Seat Belt detection overview
The Seat Belt Warning system is designed to detect when a seat is occupied and when its associated seat belt is
buckled correctly. The Seat Belt Warning system recognizes five (5) distinct seat/seat belt conditions: not occupied,
occupied and buckled, seat belt violation, buckled and not occupied, and sequence violation.
The chart below describes the conditions with the associated alarm and indications.
(RED = negative indication, GRN = affirmative indication).
TYPE CONDITION DESCRIPTION
VDR INDICATION
ALARM RED GRN
Valid Not occupied Seat is NOT occupied and associated seat belt is NOT buckled.
Valid Occupied and buckled Seat is occupied and THEN the associated seat belt is buckled.
Error Seat belt violation Seat is occupied BUT the associated seat belt is NOT buckled.
Error Buckled and not occupied Seat belt is buckled BUT the associated seat is not occupied.
Error Sequence violation Seat belt is buckled and THEN the associated seat is occupied.
Note: The VDR alarm will only sound when the park brake input is not active (see section 5.4.1.A).
The Seat Belt Warning system is designed to detect safe and unsafe conditions for seated occupants, but
the system cannot defend against tampering with the seat or seat belt switches, system modules, or
intentional manipulation of the seat and seat belt activations to circumvent safe operation. Class 1 cannot
be held responsible in these circumstances.
5.1.1. Sequence violation during power on cycle
The Seat Belt Warning input module (p/n 118093) will indicate a sequence violation for a seat position if the seat is
occupied and buckled before the input module power on cycle. This is due to the fact that the Seat Belt Warning
input module cannot determine the order of seat/seat belt activation and therefore assumes the worst case
scenario (seat belt was pre-buckled and occupant sits on top of seat belt).
This potential scenario can be eliminated by keeping the Seat Belt Warning input module powered continuously
(see section 10.1 for current draw) OR by configuring the system for loose error validation (see section 4.2.3).
5.1.2. “Seat bounce” error validation
The seat inputs of the Seat Belt Warning input module (p/n 118093) have a special two to five second bounce timer
which is designed to prevent the system from reporting a buckled and not occupied error when a buckled occupant
removes pressure from the seat’s occupant detection switch which could easily happen if an occupant adjusts their
body or the vehicle encounters a bump during operation.
The system will report a buckled and not occupied error if a buckled occupant removes pressure from the seat’s
occupant detection switch for longer than the configured “seat bounce” error validation time (see section 4.2.2).
The system can be configured to report occupied and buckled (green) OR sequence error (red) when the occupant
again sits and activates the seat switch (see section 4.2.3).