- 1 How to get voltage from ADC
- 2 Using values from external programs
- 3 Resistance measurement
- 4 Input voltage
- 5 Battery voltage
- 6 Technical details on the implementation of the ADC
How to get voltage from ADC
- Select the terminal to which your source can be connected based on the maximum allowable voltage (see table below).
- Most ADC terminals have two functions: ADC and low-voltage load control. Before measuring the voltage on the ADC, turn off the appropriate low-voltage load control output. For example, if you are connecting to terminal A1, turn off A1_OUT in the web interface (the Relays & FETs section).
- For details, see Multiplexing ports
- Connect your source to the terminal. The voltage value will immediately appear in the веб-интерфейсе in the ADCs device. The value is also translated to the MQTT message systemMQTT.
Using values from external programs
A special WB-homa-adc driver translates the value to the MQTT system and can be obtained there.
Also, the value can be obtained in manual mode:Low-level work with ADC.
Wiren Board 5.8 controllers and below were able to measure the resistance of resistors connected to the R1 and R2 inputs.
TODO: you should write here how to configure resistive inputs through the web interface.
The wb-homa-adc daemon translates the value to the MQQT message queue in the /devices/wb-adc/controls/Vin topic. Therefore, the value is displayed in the web interface as the Vin channel of the ADCs device
The wb-homa-adc daemon translates the value to the MQTT message queue in the topic /devices/wb-adc/controls/BAT. Therefore, the value is displayed in the web interface as the BAT channel of the ADCs device
Manual mode: see low-Level ADC operation.
Technical details on the implementation of the ADC
Wiren Board сontrollers versions 2.3 and 4 have 8 ADC channels that are multiplexed into one processor channel (LRADC1). Multiplexing channels are shown in the table Wiren Board 4:Список GPIO.
The Wiren Board 5 uses 8 different ADC channels that are connected to separate processor channels. The 4V line is connected to the BAT channel (LRADC7), in addition to measuring the voltage at the 2 resistive inputs, 4 universal inputs A1-A4 and the input voltage (see table below).
The ADC channels serving the R1 and R2 inputs have a built-in independent current source that is used to measure the resistance connected to the channel. Current source accuracy: 5%. See Calibration of analog inputs.
In Wiren Board 6, the ADC channels of the processor are connected to terminals A1-A4. Also, the ADC has input voltage (after the input diodes) and voltage at the terminal 5Vout.
The main channels
A part of the ADC channels is output to the terminals in parallel with the low-voltage load control transistors. Make sure you have closed the corresponding FET using GPIO before using the ADC. For details, see Multiplexing ports
A list of ADC for different devices
Wiren Board 6
Wiren Board 5
|terminal block||ADC Channel (LRADCxx)||Divider||Final formula (without divider)||V max. measured||comments|
|A1||1||88k7/12k||V = N * 3.80 mV||31V|
|R1||6||1||V = N * 0.4518 mV||3.1V||r2 = 3150 Ohm,
r1 = 1000 kOhm
|4В/li_pol||7||V = N * 1.807 mV||-||on the 4 В line|
|Vin||5||88k7/12k||V = N * 3.80 mV||31V||inpit voltage|
Terminal block || Divider || Formula to recalculate || Final formula (without divider) || V max. measured (with divider) || comments
|A1-A3||100k/90.9k||N / 4095 * 1.85V * 2.100||V = N * 0.949 mV||7.4V|
|A4-A5||100k/11.86k||N / 4095 * 1.85V * 9.43||V = N * 4.26 mV||34.4V|
|R1-R2||3k15/1M||N / 4095 * 1.85V * 1.003||V = N * 0.426 mV||3.7V|
|li_pol||100k/90.9k||N / 4095 * 1.85V * 2.100||V = N * 0.949 mV||-||battery|
|Vin||33k/4k51||N / 4095 * 1.85V * 8.32||V = N * 3.76 mV||30.6V||input voltage, iio channel 0|
|Terminal block||Divider||Formula to recalculate||Final formula||V max||comments|
|A1-A4||220k/22k||V = N / 4095 * 1.85V * 11||V = N * 4.97 mV|
|R1-R4||-||V = N / 4095 * 1.85V||V = N * 0.452 mV|
|Vin||33k/4k53||N / 4095 * 1.85V * 8.28||V = N * 3.74 mV||30V||input voltage, iio channel: 0|
|Terminal block||Divider||Formula to recalculate||Final formula (without divider)||V max. measured (with divider)||comments|
|A1-A8||31k/4.68k||N / 4095 * 1.85V * 7.627||V = N * 3.446 mV||20V|
|Vin||12k/1k||N / 4095 * 1.85V * 13||V = N * 5.873 mV||input voltage|
|Terminal block||Divider||Formula to recalculate||Final formula||comments|
|A1-A7||12K/33K||V = N / 4095 * 1.85V * 1.364||V = N * 0.616 mV|