B
[email protected]
- Jan 1, 1970
- 0
Wondering what is the best way to interface both ratiometric (absolute)
and non-ratiometric (relative) sensors to a single a/d ( an A/D with,
say, a 8 channel mux,internal ref, external ref option)
I think the most obvious is
1) Disable the internal reference, connect the ratiometric excitation
power to the external a/d reference pins (so the ratiometric sensor
outputs track with the a/d reference). For the non-ratiometric sensor
inputs read the internal reference and use that to calibrate the
non-ratiometric (absolute) readings.
or maybe,
2) Enable the internal reference so you can correctly read the
non-ratiometric reading without calibration, for the ratiometric
sensor, read its excitation power with a spare channel and use that to
calibrate the ratiometric readings.
and perhaps you can do this
3)Power the ratiometric sensor (they only require 1 mA) with an
external precision reference and also connect that reference to the
external a/d reference pins. No calibration needed for either.
and non-ratiometric (relative) sensors to a single a/d ( an A/D with,
say, a 8 channel mux,internal ref, external ref option)
I think the most obvious is
1) Disable the internal reference, connect the ratiometric excitation
power to the external a/d reference pins (so the ratiometric sensor
outputs track with the a/d reference). For the non-ratiometric sensor
inputs read the internal reference and use that to calibrate the
non-ratiometric (absolute) readings.
or maybe,
2) Enable the internal reference so you can correctly read the
non-ratiometric reading without calibration, for the ratiometric
sensor, read its excitation power with a spare channel and use that to
calibrate the ratiometric readings.
and perhaps you can do this
3)Power the ratiometric sensor (they only require 1 mA) with an
external precision reference and also connect that reference to the
external a/d reference pins. No calibration needed for either.
