StamPLC Modbus Slave

/* * SPDX-FileCopyrightText: 2024 M5Stack Technology CO LTD * * SPDX-License-Identifier: MIT */ #include <Arduino.h> #include <M5StamPLC.h> void setup() { /* Enable Modbus */ auto config = M5StamPLC.config(); config.enableModbusSlave = true; config.modbusBaudRate = 115200; config.modbusSlaveId = 1; config.enableCan = true; M5StamPLC.config(config); /* Init M5StamPLC */ M5StamPLC.begin(); } void loop() { /* Now you can control StamPLC via Modbus RS485 */ /* * Modbus Slave Configuration for M5StamPLC * ======================================= * * Register Map: * ------------- * 1. Coils (Read/Write) * - Address 0: Relay 1 output (true/false) * - Address 1: Relay 2 output (true/false) * - Address 2: Relay 3 output (true/false) * - Address 3: Relay 4 output (true/false) * * 2. Input Registers (Read-only) * - Address 0-7: Inputs (true/false) - 8 registers * - Address 8-9: Temperature (FLOAT32) - 2 registers * - Address 10-11: Bus Voltage (FLOAT32) - 2 registers * - Address 12-13: Shunt Current (FLOAT32) - 2 registers * * Note: FLOAT32 values use 2 consecutive registers (32 bits total) */ delay(1000); }

#include <ArduinoModbus.h> #include <ArduinoRS485.h> RS485Class RS485(Serial2, 39, 0, 46, -1); uint8_t slave_id = 1; // Parse two 16-bit registers into a FLOAT32 float parseFloat(uint16_t high, uint16_t low) { union { uint32_t i; float f; } value; value.i = ((uint32_t)high << 16) | low; return value.f; } void setup() { Serial.begin(115200); delay(2000); if (!ModbusRTUClient.begin(115200, SERIAL_8N1)) { Serial.println("Failed to start Modbus RTU Client"); while (1); } } void loop() { /* Now you can control StamPLC via Modbus RS485 */ /* * Modbus Slave Configuration for M5StamPLC * ======================================= * * Register Map: * ------------- * 1. Coils (Read/Write) * - Address 0: Relay 1 output (true/false) * - Address 1: Relay 2 output (true/false) * - Address 2: Relay 3 output (true/false) * - Address 3: Relay 4 output (true/false) * * 2. Input Registers (Read-only) * - Address 0-7: Inputs (true/false) - 8 registers * - Address 8-9: Temperature (FLOAT32) - 2 registers * - Address 10-11: Bus Voltage (FLOAT32) - 2 registers * - Address 12-13: Shunt Current (FLOAT32) - 2 registers * * Note: FLOAT32 values use 2 consecutive registers (32 bits total) */ Serial.println("\n--- Reading Modbus Registers ---"); // 1. Control Coils (0x01) Serial.println("Turning Relays ON:"); for (uint8_t addr = 0; addr < 4; addr++) { if (ModbusRTUClient.coilWrite(slave_id, addr, 0xFF)) { Serial.printf("Relay %d ON\n", addr); } else { Serial.printf("Failed to turn on Relay %d\n", addr); } delay(500); } Serial.println("Reading Coils Status:"); for (uint8_t addr = 0; addr < 4; addr++) { if (ModbusRTUClient.requestFrom(slave_id, COILS, addr, 1)) { Serial.printf("Relay %d: ", addr); while (ModbusRTUClient.available()) { Serial.print(ModbusRTUClient.read(), HEX); Serial.print(' '); } Serial.println(); } else { Serial.printf("Failed to read Relay %d\n", addr); } } Serial.println("Turning Relays OFF:"); for (uint8_t addr = 0; addr < 4; addr++) { if (ModbusRTUClient.coilWrite(slave_id, addr, 0x00)) { Serial.printf("Relay %d OFF\n", addr); } else { Serial.printf("Failed to turn off Relay %d\n", addr); } delay(500); } Serial.println("Reading Coils Status Again:"); for (uint8_t addr = 0; addr < 4; addr++) { if (ModbusRTUClient.requestFrom(slave_id, COILS, addr, 1)) { Serial.printf("Relay %d: ", addr); while (ModbusRTUClient.available()) { Serial.print(ModbusRTUClient.read(), HEX); Serial.print(' '); } Serial.println(); } else { Serial.printf("Failed to read Relay %d\n", addr); } } delay(500); // Read each Input Register section separately Serial.println("Reading Input Registers:"); uint16_t tempRegisters[2], voltageRegisters[2], currentRegisters[2]; float temperature, busVoltage, shuntCurrent; if (ModbusRTUClient.requestFrom(slave_id, INPUT_REGISTERS, 8, 2)) { for (uint8_t i = 0; i < 2; i++) { tempRegisters[i] = ModbusRTUClient.read(); } temperature = parseFloat(tempRegisters[0], tempRegisters[1]); Serial.printf("Temperature: %.2f°C\n", temperature); } else { Serial.println("Failed to read Temperature Registers"); } if (ModbusRTUClient.requestFrom(slave_id, INPUT_REGISTERS, 10, 2)) { for (uint8_t i = 0; i < 2; i++) { voltageRegisters[i] = ModbusRTUClient.read(); } busVoltage = parseFloat(voltageRegisters[0], voltageRegisters[1]); Serial.printf("Bus Voltage: %.2fV\n", busVoltage); } else { Serial.println("Failed to read Bus Voltage Registers"); } if (ModbusRTUClient.requestFrom(slave_id, INPUT_REGISTERS, 12, 2)) { for (uint8_t i = 0; i < 2; i++) { currentRegisters[i] = ModbusRTUClient.read(); } shuntCurrent = parseFloat(currentRegisters[0], currentRegisters[1]); Serial.printf("Shunt Current: %.2fA\n", shuntCurrent); } else { Serial.println("Failed to read Shunt Current Registers"); } Serial.printf(">>>>>> Temperature: %.2f°C, Bus Voltage: %.2fV, Shunt Current: %.2fA\n", temperature, busVoltage, shuntCurrent); delay(5000); }