Configuring the DVR
700-0042 R004 3–21
To calibrate speed:
1. Press the
POWER button only once to begin calibration.
It takes approximately two seconds for the system to be ready to start
calibration. After driving one mile, the
SPEED PULSE COUNT may be anywhere
from 2500 to 150,000, depending on the type of vehicle speed sensor being
used.
2. Press the
POWER button again to save the calibration value.
The
DVR returns to the GPS/Speed menu and the new calibrated speed pulse
count is shown.
SPEED UNIT If Speed is being recorded from the GPS receiver or the CAN
network, then the desired speed display units must be
selected. Selecting the speed unit to be
MPH makes the DVR
convert the
GPS signal to display speed in miles per hour.
If the speed display is set to pulse, the speed unit does not
matter as the calibration routine automatically sets the unit.
MPH, KPH, KTS
(knots)
MPH
SPEED
PULSE
COUNT
The EX4 DVR can record vehicle speed by counting the
number of pulses received either from a vehicle speed sensor
or a vehicle Transmission Control Module (
TCM). The DVR
must first be calibrated to the vehicle’s speed signal by
driving for one mile (kilometer) in Calibration Mode. The
DVR counts the pulses from the vehicle’s speed sensor and
then converts a pulse rate into speed. The actual distance
driven during calibration determines the unit of the speed.
For example, driving one mile during calibration results in
speed being measured in
MPH. Driving one kilometer results
in
KPH. The SPEED PULSE COUNT increments as the vehicle
travels.
2500 to 150,000 003000
CALIBRATE SPEED When calibrating speed, it is best to use known road markers
to determine a mile (kilometer) as reading the odometer may
introduce errors.
Not applicable Not
applicable
Table 3-14
GPS/SPEED configuration items
Menu Item Description Values Default
Important:
You can change the speed pulse count to either fine tune the speed display,
or to set a known value from a similar vehicle. This is useful if a fleet consists of several
models of the same bus. By calibrating one bus, the speed pulse count can then be entered
into the DVRs for all of the similar buses. However, if a DVR is moved from one bus to
another, the speed may have to be recalibrated due to differences in transmissions, tires,
and other factors.
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