Analog Input¶

Overview¶

An Analog Input reads an analog voltage on a hardware pin and converts it into a
scaled engineering value. It is the most common input type — used for any
voltage-output sensor such as temperature (NTC), pressure, throttle/pedal
position, fuel level, and similar.

The raw measured voltage is mapped to an output value using the input/output
two-point scaling below. For a non-linear sensor, feed this input into a
Map Input for multi-point scaling.

Prerequisites & hardware¶

• A sensor whose output is a voltage within the selected range.
• Wire the sensor signal to the chosen analog pin and its ground to controller ground.
• Pick the range to match the sensor's full-scale voltage so you use the full
  ADC resolution.
• Pull-up: most analog pins have no pull-up hardware, so the option is
  unavailable on the majority of inputs. Where a pin does support it, a resistive
  sensor (e.g. an NTC thermistor) can use it to form a divider instead of an
  external resistor. Otherwise, fit the divider externally.

Add it in the app¶

1. Add a new input and choose Analog Input as the type.
2. Select the pin the sensor is wired to.
3. Give it a clear alias (e.g. Oil Temp).
4. Set the range, scaling and fault thresholds below.
5. For a non-linear sensor, scale it with a Map Input.

Settings reference¶

Schema: config/AdcConfiguration.proto.

Scaling: the input is mapped from In min…In max to Out min…Out max using
two-point interpolation.
For example, a 0.5–4.5 V pressure sensor reading 0–10 bar: set In min/max to the
voltages and Out min/max to 0/10. Non-linear sensors should instead pass this
input through a Map Input for
multi-point scaling.

Common settings¶

Analog Input also uses the shared settings — alias and pin. See
Common IO Settings.

Example — coolant temperature (NTC)¶

1. Type Analog Input, alias Coolant Temp, on the sensor's pin.
2. Range 5 V. If the pin has pull-up hardware, enable Pull-up to form the
   divider with the NTC; otherwise fit the divider resistor externally.
3. Low-pass filter on (temperature changes slowly; suppress noise).
4. Feed this input into a Map Input with a voltage → °C curve from
   the data sheet (NTCs are strongly non-linear, so a two-point scale is not enough).
5. Set Fault min/max just inside the supply rails to catch an open or shorted
   sensor.

Troubleshooting¶

• Reads full-scale or zero / stuck: check wiring; the value may be sitting
  outside the Fault min/max band (open or shorted sensor).
• Value noisy / jumpy: enable the Low-pass filter.
• Reading scales wrong: verify In min/max are in the same units as the
  measured signal and that Range matches the sensor.
• Non-linear / offset reading: scale it with a Map Input rather
  than the straight in/out scale.

Related¶

• Analog Switch Input — multi-position switch on one
  analog pin.
• Map Input — multi-point scaling for non-linear sensors.
• Scaling & Maps