AiM EVO4 - Manual (Page 15)

CHAPTER 6 THE SPEED CHANNEL
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The Speed Channel.
EVO4 can receive the speed signal from
three different sources:
n The ECU
n The Built - in GPS receiver
n The two digital channels
n Gear calculation
n Distance measurement
n Data visualization in analysis software
This speed is called “Reference Speed”and
is defined in the software RaceStudio2.
n Speed read from ECU
If your ECU sends the value of speed in its
data stream, it is possible to read, record
and show that information.
Simply enable the channel in RaceStudio2
and set define this speed as "Reference
Speed."
n Speed read from GPS receiver
The GPS receiver integrated in EVO4 is con-
figured in order to obtain the best perfor-
mance in terms of reactivity and accuracy.
We know that GPS signals are extremely
weak, only 20 watts, and are transmitted
from satellites at 20.000 km away.
Data accuracy can therefore sometimes be
not as good as we would like.
However, we can say that it is generally
more than satisfactory and that GPS speed
is very often better than wheel speed.
EVO 4
It is possible that EVO4 receive and store
different values of speed at the same time:
the more powerful ECUs transmit up to four
wheel speed values; considering speed va-
lues that come from GPS and from the two
digital channels, there may be 7 different
speed values.
*Note that even if EVO4 can read and re-
cord up to seven values of speed, only ONE
of these is used for some special functions,
such as:
Speed 1-2
ECU - CAN - RS232 GPS Output
GPS Antenna