Using ADS1115 in differential mode

[e-sailing]

Code:

[ADS1115_4]
differential=1 # impossible as there are only two inputs in differential mode.

No it isn't impossible. There are 4 differential modes!!!
# 0 = Channel 0 minus channel 1        [ADS1115_1]
# 1 = Channel 0 minus channel 3        [ADS1115_2]
# 2 = Channel 1 minus channel 3        [ADS1115_3]
# 3 = Channel 2 minus channel 3        [ADS1115_4]

(you can measure up to 3 differentials not only 2!)


[quote pid='1612' dateline='1494447747']
I have used linear regression and supply an offset (added to the value from ads1115) and an intercept and a offset. The adjust_points  and adjust cover this as is, the only suggestion is that adjust_points might make polynomial or spline function to interpolate (maybe this a overkill ?).
[/quote]

Well if you use adjust_points, you don't need the offset.
The gui input of the adjust_points is only done for mcp3008 under the tab SPI. It can show you a graph of your adjust_points.
You can enter the adjust_points there and copy the line adjust_points = [...] from openplotter.conf to openplotter_analog.conf

In future we should add "differential=1" to the conf file. Thanks.