MAX31855 error
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MAX31855 error

by danjun on Wed Nov 21, 2012 11:47 am

Hi,
I have the Thermocouple board MAX 31855 and the Thermocouple K- type up to 1350C.
The problem is that the TC is NOT on this board working.
Still this output: Something wrong with thermocouple!
Internal Temp = -127.94

The TC is normally working with any other PID (up to 1300C) or on analog chip (but there is only up to 500C).

I got the MAX card today and can not find the problem.
The pins etc, lib, is all correctly connected and installed as you describe in the tutorial.
Thanks for fast reply.

Daniel
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Re: MAX31855 error

by adafruit_support_bill on Wed Nov 21, 2012 11:56 am

If you post photos of the front & back of the board we'll check the soldering. Make sure both leads are firmly clamped in the terminal blocks.

Are you using a capacitor in parallel with the TC? If so, soldering the capacitor to the back of the board usually works better than clamping both sets of leads.
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Re: MAX31855 error

by danjun on Wed Nov 21, 2012 2:25 pm

The soldering isOK.

How voltage must be measured on outputs and inputs?
The data are same if TC is or isn't connected.
how is possible test the board? Chip?

Thanks
daniel
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Re: MAX31855 error

by adafruit_support_bill on Wed Nov 21, 2012 3:12 pm

The soldering isOK.

No offense, but there are several photos here from people that said the same thing. Please post photos. :)

How voltage must be measured on outputs and inputs?
The data are same if TC is or isn't connected.
how is possible test the board? Chip?

The TC voltages are in the microvolt range. This is below the range of most multimeters. The outputs are digital signals. If you are getting an internal temp reading, your connections to the Arduino are correct. The thermocouple error is usually due to a broken thermocouple or a bad connection.
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Re: MAX31855 error

by tomaciel on Mon Feb 10, 2014 12:00 pm

Hi,

I have the same problem. I've bought the TC that you recommend.
I still get the same message.

Something wrong with thermocouple!
Internal Temp = -127.94
Error: 7

Thanks in advance.

Best regards,
António Maciel
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Re: MAX31855 error

by tomaciel on Mon Feb 10, 2014 12:00 pm

The back of the breakout board 2.0
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Re: MAX31855 error

by adafruit_support_bill on Mon Feb 10, 2014 12:14 pm

Make sure that both legs of the thermocouple are firmly clamped in the screw-terminals. Also, make sure the no part of the thermocouple is touching a grounded object.
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Re: MAX31855 error

by tomaciel on Mon Feb 10, 2014 1:25 pm

Hi,

Thanks for the reply. What do you mean if "both legs of the thermocouple are firmly clamped in the screw-terminals"?
If I try to pull the thermocouple it won't come out, it's very well screwed.
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Re: MAX31855 error

by adafruit_support_bill on Mon Feb 10, 2014 1:43 pm

If I try to pull the thermocouple it won't come out, it's very well screwed.

That should be good then. Sometimes if one leg is a little loose you can get that error. How about the tip? Is that touching anything? It should be insulated from any grounded device. Also check continuity through the thermocouple. A break in the weld can also cause that error.
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Re: MAX31855 error

by tomaciel on Mon Feb 10, 2014 2:28 pm

Hi,
´
I figured out the problem. It's in the code.

By default:
int thermoDO = 3;
int thermoCS = 4;
int thermoCLK = 5;

And it should be:
int thermoDO = 5;
int thermoCS = 4;
int thermoCLK = 3;

Thanks for the help.

Best regards,
António Maciel
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