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Using Arduino => LEDs and Multiplexing => Topic started by: Tiberio_s on Jun 06, 2017, 01:56 pm

Title: 74HC4067 with termocouple
Post by: Tiberio_s on Jun 06, 2017, 01:56 pm
Good morning!

The thermocouple needs diferential voltage to read the temperature.
I'm using mux74HC4067 to read 16 thermocouples linked in single end. I mean, I hookup all negative legs of (16) themocouples in the negative pin of ad595 and "signal" linked in positive pin of AD595. The problem is noise in the signal reads.

The question is:

How can I use two mux74HC4067 to multiplexing 16 thermocouples?
One mux with positive signal and other mux with negative signal. Each signal to the respective negative and positive pins of AD595.

Thanks!
Title: Re: 74HC4067 with termocouple
Post by: PaulRB on Jun 06, 2017, 07:29 pm
I'm not an expert on thermocouples, but I suspect the signal levels will be too low to use 4067 multiplexers like that. You may need to use 16 x AD595, one connected to each thermocouple, then use 4067 to multiplex the output signal of the AD595's into an Arduino analog input.
Title: Re: 74HC4067 with termocouple
Post by: Tiberio_s on Jun 06, 2017, 07:30 pm
ad595 is too expenssive