Reliability/accuracy of logging a mV signal (<500mV)

[roastin300]

I did a search to see what the resolution and accuracy of HPTuners Pro is when logging a mV signal but couldnt find anything.

I am installing T-Type Thermocouples (-4 to 572 deg F range) temporarily in a few locations through the vehicle on the race car to log various temperatures during runs on the road course.

The device I will use is a simple Thermocouple to Analog Converter (T-Type) that spits out a Linear 1 mV per Degree Output from the Thermocouple. AKA: -4 mV to 572 mV

My concern is I will be operating between 100 and 280 deg F mostly (100mV to 280mV), which is not much resolution of hptuners 0-5V input. How accurate is HPTuners logging something like this?

I would also assume this would be more susceptible to EMI and ground loops given its relative voltage range to the rest of the vehicle?

Thanks in advance!

-John
Roastin Performance LLC

[Nate P]

Hi John,

Normally when you use J, K or T type thermocouples, an amplifier IC is added. T types are little less common in the motorsports world, but work up to 100C with K-Type amplifiers. After 100C there will be a drift of accuracy when using a j/K amplifier with a T-type probe.. An example of an amplifier is https://www.reveltronics.com/en/prod...er-type-k-0-5v or http://thesensorconnection.com/egt-e...iABEgKTSPD_BwE

The automotive environment is harsh on electronics - I wouldn't put any effort into trying to log a signal in mV if I wanted to keep my sanity.

[roastin300]

I procured a T-Type specific amplifier immediately after posting the original message. I intend on keeping it inside the vehicle. I dont need accuracy within a degree...I am more interested in +/- 3-4 degrees maximum allowable. I am going to give it a shot and see if it seems accurate. I am going to put a Tee in with an autometer temp gauge and compare the 2 as a sanity/proof of concept test and then move forward with the T-Type thermocouple given its accurate. I am wondering if adding a voltage amplifier to the output signal between the TC amplifier and my HPTuners module would help "fill" the scale on the hptuners input. Obviously I will ground the TC amplifier device to the hptuners module as well to try and eliminate any ground loops/scaling offsets.

Thanks