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G4+ and Thermocouple for EGT


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OK, so as per the title. 

I have a Defi EGT sensor and gauge, but as I've got a CAN display in the car I want to remove the gauge and put it through the ECU for display and logging purposes. Now I thought that it would be as simple as hooking it up to an AN Temp input, but after a bit more reading a thermocouple generates a voltage (55uV per degree C, as far as I can see for a k-type), rather than a resistance, like an IAT does.

Traditionally a thermocouple would be wired into an adaptor/ amplifier (I saw a PLX Devices adaptor mentioned in a post referring to ViPec 44) to give a linear 0-5V, with temperature compensation of sorts, output which can then be scaled on any AN V input, just like an external wideband. There is Raspberry Pi K-Type adaptor/ amplifier which is VERY cheap, I'm wondering if this would do the job?

However, the PC Link help file indicates to me that it can potentially take a thermocouple input directly? I know the Thunder can, as well as wideband, but I'm running a PNP EvoLink G4+. 

I'm a little bit frustrated as I though this would be as easy as pie, but the more I've read, the less straight forward it appears to be. On the upside it's quite interesting! :D 



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The PNP link will not take a TC input directly.  I just googled the Raspberry Pi amp and most of them appear to be serial/SPI based so they will be no good to you either.  You need a 0-5V TC amp to feed into an analog input.  You can get these from many vendors, one low cost one that I know works ok is here: https://shop.vems.hu/catalog/amplifier-dsub9-p-129.html

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Thanks for the replies, the board has arrived so I'll do the modification and see what the result is I can compare it to my Defi. Certainly been interesting as I didn't realise thermocouples generated a voltage, rather than a varied resistance as with an IAT, etc. Every day is a school day!!


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  • 1 year later...
On 30.11.2016 at 9:18 AM, Adturb said:

I've had a reply on another forum and someone is successfully using the Adafruit AD 8495 board, after a minor mod to rescale it for 0-1000 Deg C. As the output is a linear 0-5V I can't see why it wouldn't work? 


What minor mod is it u did, im getting 1.322 volt out of my amplifier in 14 degres C

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  • 9 months later...

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