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How To: Custom Thermistor Tables

Old 06-20-2017, 01:51 PM
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Default How To: Custom Thermistor Tables

Came across this when curly was trying to use an AEM temperature sensor, that wasn't the standard built in temperature sensor.

Turns out megasquirt has the ability to do one custom table, but the values need to be saved in a lookup table for ADC value and temperature. So some simple math, yet time consuming.

Well I found the program that was used to generate the GM curve that we all use, and was able to generate a new .inc file.

Some links and pictures.

Tools: Index of /megasquirt/tools/win32_bin (gentherm2.exe is what we need)



That command generated the .inc file for a 2490Ohm pickup, using 3 resistance/temp pairs to generate the curve.

Then, unlock your calibrations, and go to calibrate thermistor tables, and select Custom #1 Temperature Sensor, and custom inc file.



Browse to your file, select it, and write to controller.

Here are 2 .inc files. One for a 2.2k pullup AEM temp sensor, and the other for the 2.49k pullup AEM temp sensor.
2.49k AEM
2.2k AEM
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Old 06-20-2017, 03:26 PM
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Thank you so much for going through the annoying process, I'll be trying this out in a few minutes.
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Old 06-20-2017, 04:01 PM
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Side note. We just found out this only works in 1.5.0+ firmware.
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Old 06-21-2017, 09:10 AM
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I may be missing something. Is it not possible to input sets of (3) values in TS and it generates the curve. That's what I did a few years back with my CLT probe. Put it in a chamber and read the resistance at -40, 70, and 250*, or something close to that and plugged numbers into TS and burned to MS.

Or is this in lieu of the above process when one has a published table of values? Still, one should be able to simply choose (3) sets from the table and enter them.
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Old 06-21-2017, 09:14 AM
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I think you are right. But I'm not totally sure. I may be just overcomplicating things
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