AEM 30-2204 K-Type Thermocouple Amplifier 4 Channel - Manual (Page 2)

The Advanced Engine Management (AEM) 4 channel thermocouple amplifier revolutionizes
temperature measurements by providing laboratory grade accuracy for your temperature
measurements. The accuracy is guaranteed to be better than 1% full scale, even at the extremes
of the temperature range. It is designed either for integration into vehicles already fitted with
aftermarket ECU’s or other devices that can accept an analog signal for either analysis or
logging. Alternately, an RS-232 output is available to allow other programmable devices to use
or display the thermocouple temperature data.
AEM achieves it’s accuracy by starting with a 100% surface mount PCB. The four differential
temperature inputs are fed into an A/D converter then fitted using a 3 stage, 8
th
order polynomial
curve fit. This value is then compensated using our on board cold junction temperature
measurement. The temperature values are output on four seperate 0-5v analog outputs and a 232
serial datastream.
The thermocouple amplifier can be mounted in the engine compartment or under the
dashboard. It is very light and can easily be mounted with Velcro or via the mounting holes.
CONNECTION
When routing the thermocouple wires to the amplifier, make sure to only use K-type
thermocouple wire and only use K-type thermocouple connectors. DO NOT use any other type
of connector or material in the wiring between the thermocouples and the amplifier or massive
errors will result! The required connectors to plug into the thermocouple amplifier are the “mini
blade type”.
The 9 wires should be hooked up as follows:
Color
Marking Connection
Red BATT POS Switched +12v In
Green TEMP 1 Temp #1 0-5v Output
Pink TEMP 2 Temp #2 0-5v Output
Brown TEMP 3 Temp #3 0-5v Output
Orange TEMP 4 Temp #4 0-5v Output
Yellow RS-232 TXD RS232 Transmit
Blue RS-232 GND RS232 Ground
Grey SIGNAL GND Signal Gnd (used if a differential input is required)
Black BATT NEG Battery Ground
THERMOCOUPLE
A thermocouple is a device that contains 2 differing types of metal joined at the end. The
junction between two differing metals generates a voltage which is a function of the temperature
at the junction point. While most any two metals can be used, specific materials have become the
standards because of the characteristic temperature sensitivities they possess.
The K-Type Thermocouple (Chromel/Alumel) is a general purpose thermocouple that is low
cost and available in almost every type of configuration. This is the most common type of
thermocouple in use today.
While the output voltages of different thermocouple types are known and tables are available
to show the output voltages generated at any given temperature, you can not simply monitor the
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