4-20ma
multiple slave id
I want to use esp32 read multiple Rs485 but i don't find way to set multiple slave id. Can you help me, please! This is my code: // Define an array of sensor addresses const uint8_t SENSOR_ADDRESSES[] = {0x01, 0x02, 0x03, 0x04, 0x06, 0x07, 0x08}; const int NUM_SENSORS = sizeof(SENSOR_ADDRESSES) / sizeof(SENSOR_ADDRESSES[0]);
// ... existing code ...
void setup() { // ... existing setup code ...
// Initialize ModbusMaster without specifying an address node.begin(0, Serial2); node.preTransmission(preTransmission); node.postTransmission(postTransmission);
// ... rest of setup code ... }
void loop() { // ... existing loop code ...
if (start_init == false && dataSent == true && (millis() - lastMsg >= 1000) && modeWifiSelect == "AWS") { // ... existing connection code ...
// Loop through each sensor address
for (int i = 0; i < NUM_SENSORS; i++) {
uint8_t currentAddress = SENSOR_ADDRESSES[i];
// Set the current sensor address
node.setSlaveID(currentAddress);
Serial.print("Reading sensor at address: 0x");
Serial.println(currentAddress, HEX);
// Perform read operation for the current sensor
// You'll need to adjust the register addresses and data processing for each sensor type
uint8_t result = node.readHoldingRegisters(0x0000, 4);
if (result == node.ku8MBSuccess) {
// Process and publish data for the current sensor
processSensorData(currentAddress);
} else {
handleReadError(currentAddress, result);
}
// Add a small delay between sensor reads
delay(100);
}
// ... rest of your loop code ...
}
// ... rest of your loop code ... }
void processSensorData(uint8_t sensorAddress) { // Process and publish data based on the sensor address switch (sensorAddress) { case 0x01: // O3 sensor processO3Data(); break; case 0x02: // NH4 sensor processNH4Data(); break; // Add cases for other sensor types default: Serial.println("Unknown sensor type"); } }
void processO3Data() { // Extract O3 value uint16_t O3_high = node.getResponseBuffer(2); uint16_t O3_low = node.getResponseBuffer(3);
uint32_t O3_combined = (uint32_t)O3_low << 16 | O3_high; float O3_value = ((float)&O3_combined);
String payload_O3 = "{"O3":" + String(O3_value, 2) + "}"; client.publish("v1/devices/me/telemetry", payload_O3.c_str()); }
void processNH4Data() { // Process NH4 data similarly to O3 // Adjust based on the actual data format of your NH4 sensor }
void handleReadError(uint8_t sensorAddress, uint8_t errorCode) { Serial.print("Failed to read from sensor at address 0x"); Serial.print(sensorAddress, HEX); Serial.print(". Error code: "); Serial.println(errorCode, HEX);
String sensorType = getSensorType(sensorAddress); String payload = "{"" + sensorType + "":NaN}"; client.publish("v1/devices/me/telemetry", payload.c_str()); }
String getSensorType(uint8_t sensorAddress) { switch (sensorAddress) { case 0x01: return "O3"; case 0x02: return "NH4"; case 0x03: return "NO3"; case 0x04: return "DO"; case 0x06: return "NO2"; case 0x07: return "Cl"; case 0x08: return "pH"; default: return "Unknown"; } }
// ... rest of your code ...
The code is set up to handle multiple slave IDs, and it reads data from the connected sensors sequentially. Here, I have made some changes that will be helpful to you.
Code
// I want to use ESP32 to read multiple RS485 sensors, but I don't find a way to set multiple slave IDs. Can you help me, please? This is my code:
// Define an array of sensor addresses
const uint8_t SENSOR_ADDRESSES[] = { 0x01, 0x02, 0x03, 0x04, 0x06, 0x07, 0x08 }; // SlaveID
const int NUM_SENSORS = sizeof(SENSOR_ADDRESSES) / sizeof(SENSOR_ADDRESSES[0]);
// ... existing code ...
void setup() {
// ... existing setup code ...
// Initialize ModbusMaster without specifying an address
/* Remove this
node.begin(0, Serial2);
node.preTransmission(preTransmission);
node.postTransmission(postTransmission);
*/
// ... rest of setup code ...
}
void loop() {
// ... existing loop code ...
if (start_init == false && dataSent == true && (millis() - lastMsg >= 1000) && modeWifiSelect == "AWS") {
// ... existing connection code ...
// Loop through each sensor address
for (int i = 0; i < NUM_SENSORS; i++) {
int currentAddress = SENSOR_ADDRESSES[i];
// Set the current sensor address
// node.setSlaveID(currentAddress); // Remove
// Changes
node.begin(currentAddress, Serial2);
node.preTransmission(preTransmission);
node.postTransmission(postTransmission);
// put some delay to start proper communication
// Half second delay
long int waitTime = millis();
while ((waitTime + 500) > millis()) {
}
Serial.print("Reading sensor at address: 0x");
Serial.println(currentAddress, HEX);
// Perform read operation for the current sensor
// You'll need to adjust the register addresses and data processing for each sensor type
uint8_t result = node.readHoldingRegisters(0x0000, 4);
if (result == node.ku8MBSuccess) {
// Process and publish data for the current sensor
processSensorData(currentAddress);
} else {
handleReadError(currentAddress, result);
}
// Add a small delay between sensor reads
delay(100);
}
// ... rest of your loop code ...
}
// ... rest of your loop code ...
}
void processSensorData(uint8_t sensorAddress) {
// Process and publish data based on the sensor address
switch (sensorAddress) {
case 0x01: // O3 sensor
processO3Data();
break;
case 0x02: // NH4 sensor
processNH4Data();
break;
// Add cases for other sensor types
default:
Serial.println("Unknown sensor type");
}
}
void processO3Data() {
// Extract O3 value
uint16_t O3_high = node.getResponseBuffer(2);
uint16_t O3_low = node.getResponseBuffer(3);
uint32_t O3_combined = (uint32_t)O3_low << 16 | O3_high;
float O3_value = ((float)&O3_combined);
String payload_O3 = "{" O3 ":" + String(O3_value, 2) + "}";
client.publish("v1/devices/me/telemetry", payload_O3.c_str());
}
void processNH4Data() {
// Process NH4 data similarly to O3
// Adjust based on the actual data format of your NH4 sensor
}
void handleReadError(uint8_t sensorAddress, uint8_t errorCode) {
Serial.print("Failed to read from sensor at address 0x");
Serial.print(sensorAddress, HEX);
Serial.print(". Error code: ");
Serial.println(errorCode, HEX);
String sensorType = getSensorType(sensorAddress);
String payload = "{"
" + sensorType + "
":NaN}";
client.publish("v1/devices/me/telemetry", payload.c_str());
}
String getSensorType(uint8_t sensorAddress) {
switch (sensorAddress) {
case 0x01: return "O3";
case 0x02: return "NH4";
case 0x03: return "NO3";
case 0x04: return "DO";
case 0x06: return "NO2";
case 0x07: return "Cl";
case 0x08: return "pH";
default: return "Unknown";
}
}
// ... rest of your code ...
