ADC/en
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.
Resistance measurement
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.
See ADC: resistance measurement - technical details
Input voltage
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
Battery voltage
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
See Wiren Board 6.2: Peripherals#Каналы АЦП
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 | |
| A2 | 2 | ||||
| A3 | 3 | ||||
| A4 | 4 | ||||
| R1 | 6 | 1 | V = N * 0.4518 mV | 3.1V | r2 = 3150 Ohm,
r1 = 1000 kOhm |
| R2 | 0 | ||||
| 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 |
WB4
|
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 |
WB3.5
| 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 |
WB NETMON-1
| 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 |
WB2.8
| 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 |