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How to set gain on ADCPi?

The ADC Pi is an Analogue to Digital converter for the Raspberry Pi

242 Views - Created 09/05/2023

09/05/2023

Posted by:
icenov

icenov Avatar

Hi

I'm using python3 and can read voltage on each channel OK, but I can't work out how to set the gain.

For example, using the demo_readvoltage.py script, how do I set the gain? I've tried using adc.set_gain(8) but it doesn't seem to make any difference...

Does anyone have a python example I can tryy?

Thanks

09/05/2023

Posted by:
icenov

icenov Avatar

09/05/2023

Posted by:
icenov

icenov Avatar

OK - I think I understand how it works now: voltage doesn't change but more resolution. And max voltage decreases with gain. I just wasn't sure if it was actually doing anything until I noticed that the readvoltage value was topping out at lower and lower values as the gain was increased.

09/05/2023

Posted by:
andrew

andrew Avatar

Location:
United Kingdom

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Hi

You are correct; when you set the gain to a higher value, it will read the same voltage level, but the maximum voltage decreases, and the resolution increases.

On the ADC Pi, the gain values will give the following maximum voltages.

1 = 5V

2 = 2.5V

4 = 1.25V

8 = 0.625V

13/05/2023

Posted by:
icenov

icenov Avatar

Just to check - are these +- values or just positive values?

13/05/2023

Posted by:
andrew

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Location:
United Kingdom

andrew Twitter  andrew Website  

On the ADC Pi you can only measure positive values. To measure negative values we sell the ADC Differential Pi which has a voltage range of -2.048 to +2.048V.

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