CO Sensor, analog ground reference not connected

UCF-SAEMS / Electronics

KiCad Electronic PCB design assets and documentation for the SAEMS project.

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CO Sensor, analog ground reference not connected #7

Open clayton13 opened 3 years ago

clayton13 commented 3 years ago

The LMP91000's GNDA is not directly connected to the system digital GND or to the ground of the ADC.

clayton13 commented 3 years ago

Temporary fix: simply short the localized GNDA into system global GND. This can be achieved by shorting The GNDA side of R601 or C601 to the ground pour.

Going forward: a local nettie will have to be added or GNDA should be replaced with GND.

Schematic	Options

After employing the 🔴 option above, I was able to get correct (enough) analog readings from the LMP's internal temperature sensor. The separated grounds lead to an erroneous measurement of ~0.5V over expected.