Problem with ADS1115

[nordam]

Hi,

I have a problem with my recently arrived ADS1115 4 channel ADC. I hooked it up to my Raspberry Pi, and I manage to run the example code from the Adafruit Python library, but three of the four channels always show the same value (that is, the value fluctuates a little, as I would expect, but the voltage on the three channels are always equal to each other).

My first thought was that I had made a mistake in soldering, connecting the three pins, but I checked with a multimeter and I couldn't find a problem. Also, the voltage readings only change when one of the three seemingly identical pins are connected, ignoring anything connected to the two others.

Any clues as to what might be wrong?

[adafruit_support_bill]

Hmmm. We had a similar problem in the Arduino library a while ago. Try changing line 129 of Adafruit_ADS1x15.py from:

Code: Select all

    # Wait for the ADC conversion to complete
    time.sleep(0.001)

to:

Code: Select all

    # Wait for the ADC conversion to complete
    time.sleep(0.008)

[ktownsend]

This has been fixed in the latest version of the library, which now sets the delay depending on the chip used (ADS1015 or ADS1115, which the slower 1115 needing the extra delay).