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MAX 31856
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

MAX 31856

by vip_instruments on Mon Apr 03, 2017 7:25 am

Hello There,
I want to have temperature of 3 different sensors. For which I've bought 4 units of MAX 31856 module.
Now, I'm not able to connect more than one module at a time. Please help in connecting all 3 modules to arduino UNO.

vip_instruments
 
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Re: MAX 31856

by adafruit_support_bill on Mon Apr 03, 2017 7:33 am

Wire each as described in the guide, but use a different CS pin for each sensor:
https://learn.adafruit.com/adafruit-max ... spi-wiring

When you declare the 3 sensors in your code, be sure to specify the correct CS pin number for each one:
https://learn.adafruit.com/adafruit-max ... -reference

adafruit_support_bill
 
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Re: MAX 31856

by PraveenN on Mon Nov 20, 2017 5:20 am

To Adafruit technical support,

I purchased a MAX31856 for my final year project and it was connected with a cartridge heater(24v,50W) integrated with J-type thermocouple. Temperature was displayed using the given arduino library and when the heater is operated above 5v it displays an error message "Over/Under Voltage Fault".

Here my requirement is to build a temperature controlled heater but in this case it can't be accomplished.
So I would appreciate if you could guide me to avoid this error.

Regards,

Praveen Nuwantha

PraveenN
 
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Re: MAX 31856

by adafruit_support_bill on Mon Nov 20, 2017 7:19 am

The over/under voltage fault occurs when the absolute input voltage at T+ or T- is negative or greater than VDD (3.3v). It is possible that there is some short circuit inside you heater module that is allowing higher voltages to reach the thermocouple probe.

adafruit_support_bill
 
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Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.