Channel Calibration - AEM CD-5 Quick Start Manual

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AEM CAN Sensor Module
An AEM 22 Channel CAN Sensor Module (30-2212) can be paired with a CD dash to provide analog, digital and
frequency signals for display and logging. The module is added to the Port 1/AEMnet network using the AEMnet
connector "Y" in its cable – see diagram. See CAN Sensor Module instruction manual for full installation guidelines.
AEM has supplied a number of pre-configured layouts for use with the CAN Sensor Module. The file name of each
layout describes the vehicle setup that the layout has been configured for. Vehicle setups include carburated or fuel
injected, drag race or road race, with or without AEM VDM and US or SI units. All layouts are based on the
suggested channel assignments listed in the pinout in the CAN Sensor Module instructions.

Channel Calibration

The channel data sent from the CAN Sensor Module is in a "raw" form such as voltage, frequency or resistance.
Inputs from sensors such as pressure transducers or temperature sensors can use a predefined transfer function to
go from raw units to engineering units. Other channels such as Vehicle Speed, Fuel Level and Throttle Position will
require that a calibration be performed in order to get the channel to report accurately. See the 30-2212 manual for
more details.
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Vehicle Speed - Base units is frequency. A scalar is applied to the raw frequency to get speed in MPH. The
calibration is scalar = (tire diameter inches * 0.18)/number of speed sensor trigger teeth. For example, the scalar
for a 26" tire and 12 teeth on the speed sensor trigger is (26 * 0.18)/12 which is 0.390. To set the Vehicle Speed
scalar, go Setup>Display>Scalars and locate VehicleSpeed_scalar. Using provided calibration calculation will get
speed reading very close but speed calibration can be verified with a dyno or GPS. To decrease Vehicle Speed,
decrease the VehicleSpeed_scalar value.
·
Fuel Level - Base units is Ohms. A function table is used to assign a fuel level percentage to an Ohms value.
To adjust the function table go Setup>Display>Functions and locate FuelLevelCalibration. While monitoring live
data, note the Ohms value when the tank is completely empty and also when completely full. If the change in
level sensor resistance is linear to fuel usage, the table can be left with empty and full values only. If the fuel tank
is oddly shaped and the change in level sensor resistance does not represent a linear change in fuel usage, the
function table can be setup to report a fuel level for each gallon added to the fuel tank from empty to give a more
accurate reading.
·
Throttle Position - Base units is volts. A function table is used to assign a throttle position percentage to a
voltage value. To adjust the function table go Setup>Display>Functions and locate ThrottlePosCalibration. While