Analog Tank Sensors and ADC Inputs
Tank Sensors (J16, J17, J18, J19)
Sockets J16, J17, J18, and J19 support analog tank sensors for monitoring water, grey water, black water, and fuel levels. These connectors measure tank levels using analog voltage signals from compatible sensors.
Compatible Sensors
- Votronic Tank Electrode 12-24 K and 15-50 K
- SuperSense Pro
- Resistance-based sensors (requires external circuitry)
Pinout
Each socket measures voltages between 0 and 3.3V at the signal pin, with built-in overvoltage protection. All four sockets (J16-J19) share the same pin assignment:
Specifications
- Input Range: 0-3.3V analog signal
- Signal Protection: Overvoltage protected
- Power Supply: 12V provided for sensor excitation (max. 1A total for all 4 channels)
- Power Protection: Polyfuse protected - automatically resets after short circuit detection
ADC Channel Mapping
| Connector | ADC Channel |
|---|---|
| J16 | ADC 3 |
| J17 | ADC 2 |
| J18 | ADC 1 |
| J19 | ADC 0 |
Universal ADC Inputs (J20)
Connector J20 provides four additional ADC channels (ADC 4-7) for custom analog measurements. These inputs can monitor battery voltage, temperature sensors, or other analog signals.
Voltage Divider Circuit
ADC inputs 4-7 use an internal voltage divider to extend the measurement range:
- Internal Resistor: 12 kΩ to ADC sense input
- Pull-down Resistor: 4.7 kΩ to GND
- Reference Voltage: 3.3V
- Measurement Range: 0-11.73V (without external resistor)
An optional series resistor (Rp) can be added to adjust the measurement range for specific applications.
Battery Voltage Measurement Examples
To measure battery voltages safely, an external series resistor (Rp) extends the input range. The following table shows recommended resistor values for common battery systems:
| Battery System | Max Voltage (with charging) | Series Resistor (Rp) | Measurement Range |
|---|---|---|---|
| 12V | 16V | 6.8 kΩ | 0-18.7V |
| 24V | 32V | 27 kΩ | 0-38.7V |
| 48V | 64V | 68 kΩ | 0-79.6V |
General Formula:
V_max = 3.3V × (Rp + 12kΩ + 4.7kΩ) / 4.7kΩ
Where V_max is the maximum measurable voltage at the input.
Software Integration
All ADC inputs are accessible through the adc driver in the WomoNET app. Each channel outputs a normalized float value (0.0-1.0) with unit “%”. You can configure the display range using the min/max settings in the tank widget.