66 lines
2.0 KiB
Arduino
66 lines
2.0 KiB
Arduino
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/*
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Modbus RTU Temperature Sensor
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This sketch shows you how to interact with a Modbus RTU temperature and humidity sensor.
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It reads the temperature and humidity values every 5 seconds and outputs them to the
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serial monitor.
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Circuit:
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- MKR board
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- Winners® Modbus RS485 Temperature and Humidity:
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https://www.banggood.com/Modbus-RS485-Temperature-and-Humidity-Transmitter-Sensor-High-Precision-Monitoring-p-1159961.html?cur_warehouse=CN
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- External 9-36 V power Supply
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- MKR 485 shield
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- ISO GND connected to GND of the Modbus RTU sensor and the Power supply V-
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- Power supply V+ connected to V+ sensor
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- Y connected to A/Y of the Modbus RTU sensor
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- Z connected to B/Z of the Modbus RTU sensor
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- Jumper positions
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- FULL set to OFF
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- Z \/\/ Y set to ON
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created 8 August 2018
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by Riccardo Rizzo
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*/
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#include <ArduinoModbus.h>
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float temperature;
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float humidity;
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void setup() {
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Serial.begin(9600);
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while (!Serial);
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Serial.println("Modbus Temperature Humidity Sensor");
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// start the Modbus RTU client
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if (!ModbusRTUClient.begin(9600)) {
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Serial.println("Failed to start Modbus RTU Client!");
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while (1);
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}
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}
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void loop() {
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// send a Holding registers read request to (slave) id 1, for 2 registers
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if (!ModbusRTUClient.requestFrom(1, HOLDING_REGISTERS, 0x00, 2)) {
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Serial.print("failed to read registers! ");
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Serial.println(ModbusRTUClient.lastError());
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} else {
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// If the request succeeds, the sensor sends the readings, that are
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// stored in the holding registers. The read() method can be used to
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// get the raw temperature and the humidity values.
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short rawtemperature = ModbusRTUClient.read();
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short rawhumidity = ModbusRTUClient.read();
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// To get the temperature in Celsius and the humidity reading as
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// a percentage, divide the raw value by 10.0.
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temperature = rawtemperature / 10.0;
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humidity = rawhumidity / 10.0;
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Serial.println(temperature);
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Serial.println(humidity);
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}
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delay(5000);
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}
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