PH and Temperature Transmitter RS485

Technical parameter

• Measuring range pH: 0.0~14.0
• Measuring range temperature: -20°C ~+80°C
• Measurement accuracy pH: ±0.1PH
• Measurement accuracy temperature: ± 0.5°C
• Working voltage DC: 12V ~ 24V (ripple< 50mV)
• Signal output: ModbusRTU485
• Power waste: <1W 
• Storage environment temperature: 10°C - 50°C (-20°C ~ +80°C peak)
• Storage environment humidity: 20 - 60%RH
• Work environment temperature: -20°C ~+80°C
• Work environment humidity: 5 - 95%RH (non-condensing)
• Shape size: 65mm*46mm*28.5mm

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's Temperature And pH

Inquiry Frame

Answer Frames

How to calculate Temperature And pH

Temperature = FF33 H = -205 = -20.5°C

 pH = 28 H = 40 = 4.0

#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 //Address ของเซ็นเซอร์

SoftwareSerial mySerial(RXD, TXD);
ModbusMaster node;

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

}

void loop() {
get_pht485();

}

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_pht485() {
#define pH_REG 1 //Register Address 0001H
#define TEMPERATURE_REG 0 //Register Address 0000H
float Temperature, ph; //ประกาศตัว ตแปลแ แบบทดศนิยม
ph = get_modbusRTU_sensor(slaveID, pH_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("pH = ");
Serial.print(ph, 1);
Serial.println("");
}