Modbus RTU Slave Firmware with ADS1015 and real-time RMS calculation (ESP32). More...

#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_ADS1X15.h>
#include "HardwareSerial.h"
#include "ModbusServerRTU.h"

Classes
struct	ADC_Sample
	ADC sample with value and associated channel. More...
struct	RMS_FIFO
	Circular buffer for efficient RMS calculation. More...
struct	SensorData
	Sensor configuration parameters for Modbus discovery. More...

Macros
#define	I2C_SDA_PIN 9
	I2C SDA pin for ADS1015 communication.
#define	I2C_SCL_PIN 8
	I2C SCL pin for ADS1015 communication.
#define	ADS_ALERT_PIN 10
	ADS1015 interrupt pin for completed conversions.
#define	SLAVE_ID 1
	Modbus slave device address.
#define	NUM_REGISTERS 18
	Total number of Modbus registers available for RMS data.
#define	RX_PIN 20
	UART receive pin for RS485.
#define	TX_PIN 21
	UART transmit pin for RS485.

Functions
HardwareSerial	ModbusSerial (1)
	Serial port instance for Modbus RS485 communication.
ModbusServerRTU	MBserver (2000)
	Modbus RTU server with 2000ms timeout.
void IRAM_ATTR	on_adc_data_ready ()
	Interrupt service routine for completed ADC conversions.
void	task_adquisicion (void *pvParameters)
	ADC data acquisition task with improved multiplexer handling.
void	task_procesamiento (void *pvParameters)
	Sample processing and RMS calculation task.
int	get_rms_history (int channel, float *output_buffer, int count)
	Gets RMS value history for a specific channel.
void	dataUpdateTask (void *pvParameters)
	Modbus register update task with per-channel conversion factors.
ModbusMessage	readHoldingRegistersWorker (ModbusMessage request)
	Worker to handle Modbus holding register read requests.
void	setup ()
	System initialization function.
void	loop ()
	System main loop.

Variables
const int	NUM_CHANNELS = 3
	Number of ADC channels to sample.
const int	FIFO_SIZE = 320
	Circular FIFO buffer size for RMS calculation.
const int	PROCESS_INTERVAL_MS = 1000
	RMS processing interval in milliseconds.
const int	RMS_HISTORY_SIZE = 100
	RMS value history size for each channel.
const int	MODBUS_UPDATE_INTERVAL_MS = 300
	Modbus register update interval in milliseconds.
const float	CONVERSION_FACTOR = 0.618f
	Global conversion factor (maintained for compatibility).
const float	CONVERSION_FACTORS [NUM_CHANNELS]
	Channel-specific conversion factors for each ADC channel.
Adafruit_ADS1015	ads
	ADS1015 converter instance.
QueueHandle_t	queue_adc_samples
	Communication queue for ADC samples.
RMS_FIFO	fifos [NUM_CHANNELS]
	Array of FIFOs for each measurement channel.
float	rms_history_ch0 [RMS_HISTORY_SIZE]
	RMS value history for channel 0.
float	rms_history_ch1 [RMS_HISTORY_SIZE]
	RMS value history for channel 1.
float	rms_history_ch2 [RMS_HISTORY_SIZE]
	RMS value history for channel 2.
volatile int	rms_history_head = 0
	Write index for RMS histories.
SemaphoreHandle_t	rms_history_mutex
	Mutex for concurrent access protection to RMS histories.
volatile bool	adc_data_ready = false
	ADC data ready flag (ISR).
volatile uint8_t	current_isr_channel = 0
	Current channel in sampling sequence (ISR).
uint16_t	holdingRegisters [NUM_REGISTERS]
	Modbus registers for RMS data.
SemaphoreHandle_t	dataMutex
	Mutex for Modbus register protection.
TaskHandle_t	dataUpdateTaskHandle
	Handle for Modbus data update task.
SensorData	sensor = {1, 3, 10, NUM_REGISTERS, PROCESS_INTERVAL_MS, 1, 1, 0}
	Sensor configuration for discovery responses.

Detailed Description

Modbus RTU Slave Firmware with ADS1015 and real-time RMS calculation (ESP32).

This system acquires analog signals from 3 channels using ADS1015 ADC, calculates real-time RMS values using circular FIFOs, maintains a measurement history and responds to Modbus RTU queries over RS485. Includes channel-specific conversion factors and improved ADC multiplexer handling.

Date: 2025-12-04

Classes

Macros

Functions

Variables

Detailed Description