On June 10 I ordered 3 MAX31855 breakout boards. I was thrilled to get them so quickly, and got them all communicating with my Arduino in no time flat thanks to your tutorials. Initially though I only had one thermocouple to test the three out with. Everything looked OK near room temperature (maybe reading a little too low, like 34.5 celsius instead of 36, but I figured it was within their quoted accuracy and I could correct any linear offset in software later).
Unfortunately, once I got my order of thermocouples from OMEGA I tested out all three MAX31855 simultaneously. They don't really agree with each other very well, so I tested out the MAX31855 boards with hot and cold baths and used another thermometer for reference. I used a "FLUKE 51 II THERMOMETER" and an expensive temperature controller with platinum 1 kiloohm resistance temperature detector (with an absurdly precise millikelvin readout). These two references have nearly identical accuracy as far as I can tell -- but both differ from the MAX31855 readings by significant amounts (nearly 10 degrees celsius when measuring a 70 degree celsius bath). I double checked, and the MAX31855 chip on the board is for the K-type thermocouples which I have.
From searching the Adafruit support forum, and reading a thread on the eevblog forum, it appears the MAX31855 chips on my breakout boards might come from a bad batch Maxim released. Is there any way to get these replaced? I'm more than happy to ship these back to you.
MAX31855 Thermocouple Amplifier Breakout Board Giving Bad Re
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Please be positive and constructive with your questions and comments.
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- Franklin97355
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Re: MAX31855 Thermocouple Amplifier Breakout Board Giving Ba
There was a bad batch of the amplifiers. could you post a clear picture of the chip or copy off the code from the chip and post that?
The label of the chip on the breakout board:
M31855k
1345A2
253AK (also 253AJ I think)
The label of the chip on the breakout board:
M31855k
1345A2
253AK (also 253AJ I think)
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Re: MAX31855 Thermocouple Amplifier Breakout Board Giving Ba
After trying to photograph it a dozen times, this is the best I got
All three MAX31855 chips say
"M31855K
1345A2
253AK"
All three MAX31855 chips say
"M31855K
1345A2
253AK"
- Franklin97355
- Posts: 23912
- Joined: Mon Apr 21, 2008 2:33 pm
Re: MAX31855 Thermocouple Amplifier Breakout Board Giving Ba
Thanks. Please email [email protected] with a link to this thread for a refund at this time we don't have any confirmed good stock. If you want to get a notification when they come in visit this page https://www.adafruit.com/product/269
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Re: MAX31855 Thermocouple Amplifier Breakout Board Giving Ba
Thank you franklin97355. I'm a bit bummed out, but I realize it's not adafruit's fault. Thanks for your help.
Please be positive and constructive with your questions and comments.