hi guys:
I am trying to connect several thermocouple sensors to one MAX31855 Module through multiplexer. I don't know how it could possible work. I see the thermocouple has + and - side to connect. Does anyone know how to do it?
about using several thermocouple with a multiplexer
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
-
- Posts: 16
- Joined: Sat Jan 05, 2013 1:09 am
- adafruit_support_mike
- Posts: 67454
- Joined: Thu Feb 11, 2010 2:51 pm
Re: about using several thermocouple with a multiplexer
That's kind of tricky..
A normal multiplexer wouldn't work. Those are generally digital and thermocouples produce low-voltage analog signals. To select one of several thermocouples, you'd need analog switches.
The 74HC4066 is a traditional 4-channel analog switch, but its on-resistance is about 50 ohms. I'm not sure what that would do to a thermocouple's calibration. You can get analog switches whose on-resistance is less than an ohm (http://www.mouser.com/ProductDetail/Tex ... 2fp0bFw%3d) but they tend to come in really tiny packages.
Reed switches/relays would probably be your best choice.
A normal multiplexer wouldn't work. Those are generally digital and thermocouples produce low-voltage analog signals. To select one of several thermocouples, you'd need analog switches.
The 74HC4066 is a traditional 4-channel analog switch, but its on-resistance is about 50 ohms. I'm not sure what that would do to a thermocouple's calibration. You can get analog switches whose on-resistance is less than an ohm (http://www.mouser.com/ProductDetail/Tex ... 2fp0bFw%3d) but they tend to come in really tiny packages.
Reed switches/relays would probably be your best choice.
Please be positive and constructive with your questions and comments.