MODBUS

[frasanc]

We use that PIN photo to identify A-B PIN.

// src/modbus_reader.cpp
void ModbusReader::applyUartPins(uint32_t baudRate) {
    int8_t rxPin = RS485_RX_PIN;   // 15
    int8_t txPin = RS485_TX_PIN;   // 7
    if (s_rs485SwapTxRx) {
        rxPin = RS485_TX_PIN;      // swap: begin(9600, 8N1, 7, 15)
        txPin = RS485_RX_PIN;
    }
    _serial.begin(baudRate, MODBUS_SERIAL_CFG, rxPin, txPin);
}

```cpp
ModbusResult ModbusReader::readInputRegisters(uint8_t slaveId,
                                              uint16_t startAddress,
                                              uint8_t count) {
    flushRxQuiet();
    _node.begin(slaveId, _serial);
    uint8_t status = _node.readInputRegisters(startAddress, count);
    silentBusGapAfterFrame();
    // On success: values = _node.getResponseBuffer(i);
}

I put here some examples I'm following, including change pin number according your suggestion but is not working. I don't know if there is som example for that board.