Temperature and Humidity transmitter RS485 output with display

Technical parameter

• Power supply : 7-36VDC
• Maximum power consumption : 0.4W
• Display : OLED 0.96 inch
• Temperature Range : -40°C - 80°C (เซ็นเซอร์อุณหภูมิสามารถวัดค่าได้ -40 °C -125 °C )
• Humidity Range : 0% RH - 100% RH
• Accuracy humidity : ± 3%RH (5% RH - 95% RH, 25°C)
• Accuracy temperature : ± 0.5°C (25°C)
• Transmitter circuit operating temperature : -20°C - 60°C, 0% RH - 80% RH
• Long-term stability Humidity : ≤1% RH / y
• Long-term stability Temperature : ≤0.1C / y
• Response time humidity : ≤6S (1m / s)
• Response time temperature : ≤18S (1m / s)
• Communication interface : RS485

Interface Description

          Before you wiring and use, please read this article in detail, Improper use may result in irreversible damage to the product.

Communication protocol

Register Address

Communication example

          Read Device Address 0x01 Temperature and Humidity

Inquiry Frame

 Answer Frames

How to calculate Temperature and Humidity

          Temperature : FF9BH (Hexadecimal) = -101 = -10.1°C

          Humidity : 292H (Hexadecimal) =658=> humidity = 65.8%RH

How to set up THD-031(dip switch) Sensor

#include <ModbusMaster.h> //https://www.arduinolibraries.infoModbusMaster/libraries/modbus-master
#include <SoftwareSerial.h> //https://github.com/PaulStoffregen/SoftwareSerial
#define TXD 4 // your software serial TXD pin
#define RXD 3 // your software serial RXD pin
#define slaveID 1

SoftwareSerial mySerial(RXD, TXD);

ModbusMaster node;

void setup() {
Serial.begin(9600); // config baudrate modbus
mySerial.begin(9600);

}

void loop() {
get_th031();

}

int get_modbusRTU_sensor(int addr , uint16_t REG) {
int result;
node.begin(addr, mySerial);
//result = node.readInputRegisters (REG, 2); ///< Modbus function 0x04 Read Input Registers
result = node.readHoldingRegisters (REG, 2);
if (result == node.ku8MBSuccess) {
return node.getResponseBuffer(0);
} else {
//Serial.print("Connec modbus fail. REG >>> "); mySerial.println(REG, HEX); // Debug
return -270;
}
}

/************************TH-031**************************/
void get_th031() {
#define HUMIDITY_REG 0
#define TEMPERATURE_REG 1
float Temperature, Humidity;
Humidity = get_modbusRTU_sensor(slaveID, HUMIDITY_REG) / 10;
delay(1000);
Temperature = get_modbusRTU_sensor(slaveID, TEMPERATURE_REG) / 10;
delay(1000);
Serial.print("Temperature = ");
Serial.print(Temperature, 1);
Serial.print("C,");
Serial.print("Humidity = ");
Serial.print(Humidity, 1);
Serial.println("%RH");
}