+- OpenMarine (https://forum.openmarine.net)
+-- Forum: OpenPlotter (https://forum.openmarine.net/forumdisplay.php?fid=1)
+--- Forum: How do I...? (https://forum.openmarine.net/forumdisplay.php?fid=3)
+--- Thread: DIFFERENTIAL MODE ADS1115 (/showthread.php?tid=5243)
DIFFERENTIAL MODE ADS1115 - SARASTRO - 2024-03-10
Is possible to configure I2C in OP3 for differential mode measuring a signal?
OP3 detects the four channels for single-ended connection, but I do not know how to configure differential mode.
(Using A0-A!, or A2-A3)
Thanks for help!
RE: DIFFERENTIAL MODE ADS1115 - PaddyB - 2024-03-11
(2024-03-10, 09:52 PM)SARASTRO Wrote: Is possible to configure I2C in OP3 for differential mode measuring a signal?
OP3 detects the four channels for single-ended connection, but I do not know how to configure differential mode.
(Using A0-A!, or A2-A3)
Thanks for help!
Can't help with the exact question but worth noting that the ADS1115 isn't "real" differential, it measures just measures the 2 channels voltage above ground & subtracts one from the other internally.
RE: DIFFERENTIAL MODE ADS1115 - SARASTRO - 2024-03-11
Many thanks, Paddy,
I want to avoid the possible offset between the GND on the RPI and the negative pole of the batteries when measuring the voltage.
In any case, the ADAFRUIT technical documentation recommends the differential mode as the most immune to distortions caused by very long cables. This is my case.
But I will have to test it on the boat and see if this GND offset really exists, and the precision I get with the single end connection
RE: DIFFERENTIAL MODE ADS1115 - PaddyB - 2024-03-11
(2024-03-11, 02:00 PM)SARASTRO Wrote: Many thanks, Paddy,
I want to avoid the possible offset between the GND on the RPI and the negative pole of the batteries when measuring the voltage.
In any case, the ADAFRUIT technical documentation recommends the differential mode as the most immune to distortions caused by very long cables. This is my case.
But I will have to test it on the boat and see if this GND offset really exists, and the precision I get with the single end connection
Might be worth trying connecting the ground of the ads1115 direct to the battery negative? I´ve been doing something similar measuring LiFePo4 cell voltages and ended up using opamps to change differential voltages into voltage above ground but that starts to get pretty complicated. For my google/youtube education anyway ?