RS-LDO-N01-1 — Auto Scanner

DO_sensor_auto_scanner.ino

/* -------------------------------------------------------------------------- */
/*         RS-LDO-N01-1 — Auto Scanner (address + baud rate)                 */
/* -------------------------------------------------------------------------- */

#include <Arduino.h>
#include <SoftwareSerial.h>
#include <ModbusMaster.h>

EspSoftwareSerial::UART mySerial;

#define MAX485_DE 4
#define MAX485_RO 18
#define MAX485_DI 19

ModbusMaster node;

void preTransmission()  { digitalWrite(MAX485_DE, 1); }
void postTransmission() { digitalWrite(MAX485_DE, 0); }

float convertRegistersToFloat(uint16_t reg0, uint16_t reg1) {
  union { uint8_t b[4]; float f; } c;
  c.b[3] = (reg0 >> 8) & 0xFF;
  c.b[2] =  reg0       & 0xFF;
  c.b[1] = (reg1 >> 8) & 0xFF;
  c.b[0] =  reg1       & 0xFF;
  return c.f;
}

// All baud rates listed in the manual
const uint32_t BAUD_RATES[] = { 4800, 9600, 2400, 19200, 38400, 57600, 115200, 1200 };
const uint8_t  BAUD_COUNT   = sizeof(BAUD_RATES) / sizeof(BAUD_RATES[0]);

// Found device info
bool     deviceFound    = false;
uint32_t foundBaud      = 0;
uint8_t  foundAddress   = 0;

void tryBaudAndAddresses(uint32_t baud) {
  Serial.printf("\n>>> Trying baud rate: %lu\n", baud);

  mySerial.end();
  delay(50);
  mySerial.begin(baud, EspSoftwareSerial::SWSERIAL_8N1,
                 MAX485_RO, MAX485_DI, false, 95, 11);
  delay(100);

  // Try address 1 first (factory default), then 2–10, then the rest up to 247
  // Full Modbus range is 1–247; address 0 is broadcast (skip)
  for (uint16_t addr = 1; addr <= 247; addr++) {
    node.begin((uint8_t)addr, mySerial);
    node.preTransmission(preTransmission);
    node.postTransmission(postTransmission);

    uint8_t result = node.readHoldingRegisters(0x0000, 6);

    if (result == node.ku8MBSuccess) {
      float do_sat   = convertRegistersToFloat(node.getResponseBuffer(0), node.getResponseBuffer(1));
      float do_conc  = convertRegistersToFloat(node.getResponseBuffer(2), node.getResponseBuffer(3));
      float temp_c   = convertRegistersToFloat(node.getResponseBuffer(4), node.getResponseBuffer(5));

      // Sanity-check: values must be in plausible physical range
      bool sane = (do_sat  >= 0.0f && do_sat  <= 200.0f) &&
                  (do_conc >= 0.0f && do_conc <= 20.0f)  &&
                  (temp_c  >= 0.0f && temp_c  <= 40.0f);

      if (sane) {
        Serial.println("\n========== DEVICE FOUND ==========");
        Serial.printf("  Baud rate : %lu\n", baud);
        Serial.printf("  Address   : %d (0x%02X)\n", addr, addr);
        Serial.printf("  DO Sat    : %.2f %%\n",   do_sat);
        Serial.printf("  DO Conc   : %.2f mg/L\n", do_conc);
        Serial.printf("  Temp      : %.2f °C\n",   temp_c);
        Serial.println("==================================");

        deviceFound  = true;
        foundBaud    = baud;
        foundAddress = (uint8_t)addr;
        return;
      }
    }

    // Small gap between attempts to let the bus settle
    delay(30);

    // Print a dot every 20 addresses so you can see progress
    if (addr % 20 == 0) Serial.print('.');
  }
}

void setup() {
  Serial.begin(115200);
  while (!Serial);

  pinMode(MAX485_DE, OUTPUT);
  digitalWrite(MAX485_DE, 0);

  Serial.println("\nRS-LDO-N01-1 Auto Scanner");
  Serial.println("Scanning all baud rates x addresses 1-247 ...");

  for (uint8_t b = 0; b < BAUD_COUNT && !deviceFound; b++) {
    tryBaudAndAddresses(BAUD_RATES[b]);
  }

  if (!deviceFound) {
    Serial.println("\n[FAIL] Device not found on any baud rate or address.");
    Serial.println("Check wiring: Brown=12V, Black=GND, Yellow/Green=A, Blue=B");
  }
}

void loop() {
  if (!deviceFound) {
    delay(5000);
    return;
  }

  // Normal polling loop once device is found
  node.begin(foundAddress, mySerial);

  uint8_t result = node.readHoldingRegisters(0x0000, 6);
  if (result == node.ku8MBSuccess) {
    float do_sat  = convertRegistersToFloat(node.getResponseBuffer(0), node.getResponseBuffer(1));
    float do_conc = convertRegistersToFloat(node.getResponseBuffer(2), node.getResponseBuffer(3));
    float temp_c  = convertRegistersToFloat(node.getResponseBuffer(4), node.getResponseBuffer(5));

    Serial.printf("[Addr:0x%02X @ %lu baud]  DO: %.2f mg/L  Sat: %.1f%%  Temp: %.1f°C\n",
                  foundAddress, foundBaud, do_conc, do_sat, temp_c);
  } else {
    Serial.printf("[WARN] Read failed (err 0x%02X)\n", result);
  }

  delay(2000);
}