afe_baseline - bruno-beloff/scs_mfr GitHub Wiki

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DESCRIPTION

The afe_baseline utility is used to adjust the zero offset for electrochemical sensors, as interpreted by the Alphasense application note AAN 803-02.

A positive offset value cause the result to be higher - if the system reports a concentration of 25 parts per billion in zero air, its zero offset should be set to -25. The date / time of any change is recorded.

Each sensor is identified by the gas that it detects. For example, a nitrogen dioxide sensor is identified as NO2, and an ozone sensor is identified as Ox.

Note that the scs_dev/gasses_sampler process must be restarted for changes to take effect.

SYNOPSIS

afe_baseline.py [{ -b GAS | { -s | -o } GAS VALUE | -c GAS CORRECT REPORTED | -z | -d }] [-v]

Options
--version	show program's version number and exit
-h, --help	show this help message and exit
-b BASELINE, --baseline=BASELINE	report offset for GAS
-s SET, --set=SET	set offset for GAS to integer VALUE
-o OFFSET, --offset=OFFSET	change offset for GAS, by integer VALUE
-c CORRECT, --correct=CORRECT	change offset for GAS, by the difference between CORRECT and REPORTED values
-z, --zero	zero all offsets
-d, --delete	delete the baseline configuration
-v, --verbose	report narrative to stderr

EXAMPLES

./afe_baseline.py -c NO2 10 23

DOCUMENT EXAMPLE

{"sn1": {"calibrated-on": "2019-02-02T12:00:48Z", "offset": 123}, "sn2": {"calibrated-on": "2019-02-02T11:30:17Z", "offset": 0}, "sn3": {"calibrated-on": "2019-02-02T11:30:17Z", "offset": 0}, "sn4": {"calibrated-on": "2019-02-02T11:30:17Z", "offset": 0}}

FILES

~/SCS/conf/afe_baseline.json