TrimTrac ProE Locator, Technical Manual

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TrimTrac ProE Locator Technical Manual v2.0e 85
DELAY: The device disables the motion sensor wakeup and goes to sleep for a
programmable DELAY Timeout, T4. When the unit wakes up it transitions to the
IDLE state by enabling the motion sensor and going back to sleep. The programmable
DELAY Timeout, T4, is stored as seconds and is typically on the order of 10 to 20
minutes. If In-Motion Polling is set “1=OnDemand while in Motion” or Anytime
Polling is set “2=Anytime OnDemand”, then the GSM modem will remain
operational during DELAY and the unit will be able to receive and process data
messages.
Motion Detection and Filtering
In most applications, motion-based reporting is the fundamental operating premise of
the TrimTrac ProE. The TrimTrac ProE includes a mechanical motion detector that is
very sensitive to shock, vibration, tilting and motion.
There are three layers of filtering on the motion detector output. First, the device
counts of the number of times motion is detected in each second. If the number of
counts exceeds the threshold determined by Motion Counter Threshold, then motion
is recognized as having occurred in that second. At its default setting, the Motion
Counter Threshold must sense at least 10 instances of motion per second before
motion in that second is recognized.
Next, the TrimTrac keeps track of how many seconds have exceeded the Motion
Counter Threshold within a configurable sampling period. The length of the sample
period is determined by Static Motion Filter Timeout, T7 and Dynamic Motion Filter
Timeout, T21 depending upon whether the device is stationary or is in motion,
respectively. Both the static and dynamic motion filters use a rolling time window
during which it counts the number of seconds that motion occurred (Static Motion
Filter Counter, N3, and Dynamic Motion Filter Counter, N4, respectively).
For instance, if the device is stationary, it will wake up and leave the IDLE state when
the number of seconds during which new motion occurred, according to the Motion
Counter Threshold setting, exceeds the setting of Static Motion Filter Counter, N3,
during the trailing time period determined by Static Motion Filter Timeout, T7.
Conversely, if the number of seconds during which motion occurred, according to the
Motion Counter Threshold setting, exceeds the setting of Dynamic Motion Filter
Counter, N4, during any period determined by Dynamic Motion Filter Timeout, T21,
then the device continues cycling through the State Machine.
State Machine Design Details
As seen in Figure 23 on page 83 the state machine has six primary states that
represent the basic operation of the device. This section gives a detailed
description of each state, what events trigger transitions from each state, and the
processing that occurs within each state and during the transition between states.
There are two status variables used along with the state of the TrimTrac ProE:
TriggerType; and
ReportType