ADS 1115

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cameron_whitehead
 
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ADS 1115

Post by cameron_whitehead »

Good day,
I recently got a couple of ADS1115 that I am wanting to use with a raspberry pi for data logging. However, after following the instructions on how to setup and get my adc working, I am not getting stable results.
I have an old BK Precision DC Power Supply 1610 that I set up to power a simple DC circuit to test the ADS1115. The circuit simply has 2 10k resistors in series to create a high middle and low voltage point. The voltage applied is only 2v to ensure I don't go over the ADC's max of 3.3v. I checked it with a multimeter to ensure that I was getting the appropriate voltage. The gain was left at 1 to measure over the 4v range.
When I run the python code on the pi, even though I only connect A0 to a point on the circuit, the results jump all over the place on all 4 channels. This happens at 0, 1, or 2 volts. I have 2 of the ads 1115, and they are both doing the same thing.
I am stumped. I figured this would be "plug and play", but something is not working right.

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Franklin97355
 
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Re: ADS 1115

Post by Franklin97355 »

Do you have a ground between the ADS and your test circuit?

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cameron_whitehead
 
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Re: ADS 1115

Post by cameron_whitehead »

No. They are separate circuits.

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Franklin97355
 
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Re: ADS 1115

Post by Franklin97355 »

Can you post a diagram of your test circuit? You should have both A0 and ground connected to the test points.

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cameron_whitehead
 
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Re: ADS 1115

Post by cameron_whitehead »

SimpleCircuit.jpg
SimpleCircuit.jpg (41.28 KiB) Viewed 353 times
I hope this makes sense to you.

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Franklin97355
 
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Re: ADS 1115

Post by Franklin97355 »

You need a ground between the power supply and the ADS1115 ground as a reference for the analog reading.

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cameron_whitehead
 
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Re: ADS 1115

Post by cameron_whitehead »

Worked like a charm. Thanks.

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