Megasquirt-2 Setting Up
4:Advanced topics
Offset = 75
4.9.8 Example Settings - other devices
Information request - if you have settings that work with other standard Megasquirt devices, please post on
the
forum, so that information can be included here.
4.10 Reading and Datalogging an Additional Sensor
The Megasquirt-2 ECUs typically have two 'spare' ADC (analog) inputs that you can use to read and datalog
an additional analog sensor. e.g. pressure, temperature. (For reference, the configuration in Megasquirt-3 is
far simpler.)
4.10.1 Wiring
Refer to the Hardware Manual for your product for details on how to wire in an additional analog sensor. The
processor requires a 0-5V signal.
4.10.2 TunerStudio custom.ini
The additional sensor signal is converted to a digital number (0-1023) by the Megasquirt-2. To convert that
raw number into something more meaningful, you need to create or edit a file called "custom.ini" that
instructs TunerStudio to process that number. You can then display a gauge on your tuning computer and
record the value in datalogs.
Before you start, make SURE that you turned off the option to "Hide known file extensions" in Windows.
Use a text editor (e.g. Notepad on Windows) and create some custom configuration. The 'custom.ini' file
uses a kind of programming language. The equations are case sensitive and can silently fail if you get the
case wrong!
e.g.
The above example reads from the two spare analogue inputs:
adc6 = JS5 / SPAREADC
adc7 = JS4 / SPAREADC2
The variables 'adc6' and 'adc7' are already defined in the main 'ini' file and are equal to the raw ADC count
from the analogue inputs.
The [OutputChannels] section gives definitions of new variables. Here 'OilTemp' is defined as a table lookup
from a provided lookup table file "ntcbosch.inc". 'Oilpress' is a linear equation.
The [Datalog] section specifies what additional fields should be added to the datalog.
(c) 2014-9 James Murray
2019-01-11
Page 81/117
