Example Code for Arduino-Output 10mA Current

Hardware Preparation

• DFRduino UNO R3 (or similar) x 1
• Gravity: I2C 4-20mA DAC Module(SKU: DFR0972) x 1
• Multimeter x 1
• Resistance of 220Ω~650Ω (greater than 1/8 watt) x 1
• Experimental Power supply
• M-M/F-M/F-F Jumper wires

Software Preparation

• Download Arduino IDE: Click to download Arduino IDE.
• Download and install the DFRobot_GP8302.
• For Arduino IDE V1.8.19 (or earlier), install the library manually: How to Add a Library？
• For Arduino IDE V2.0.0 (or later), directly search for the "DFRobot_GP8302" in the Library Manager and install it.

Wiring Diagram

Step 1: Insert the probe of the multimeter into the jack for current, and change it to DC current, as shown in the figure：

Step 2: Adjust the voltage of the experimental power supply to 24V, as shown in the figure：

Step 3: Connect the UNO main board, the experimental power supply, the current module, the load resistor and the multimeter according to the figure：

The test proved that the result is incorrect when using load meter as load resistor, because the load meter is not a pure resistance load, which will lead to inaccurate output voltage.

Notice

Write and download the following code into the UNO main board to make the current module output a current of 10mA, and save the value in the module. Changing the value in the "module.output(10)" function can change the output current, the range of the value is 0-25, corresponding to 0-25mA respectively.

Sample Code

Code initializes GP8302 module, outputs 10mA current, saves config (not lost after power-off).

#include "DFRobot_GP8302.h"

DFRobot_GP8302 module;

void setup(){
  Serial.begin(115200);

  while(!Serial){

  }
  Serial.print("I2C to 0-25 mA analog current moudle initialization ... ");
  uint8_t status = module.begin(); // use the pin used by the I2C Wire object of the MCU hardware by default

  if(status != 0){
    Serial.print("failed. Error code: ");
    Serial.println(status);
    Serial.println("Error Code: ");
    Serial.println("\t1: _scl or _sda pin is invaild.");
    Serial.println("\t2: Device not found, please check if the device is connected.");
    while(1) yield();
  }
  Serial.println("done!");

  uint16_t dac = module.output(10); //control the converter module to output a current of 10mA and return the corresponding DAC value
  Serial.print("DAC value: 0x"); Serial.println(dac, HEX);
  module.store(); Serial.println("Save current configuration."); //the above current config will be saved and will not be lost after power off
}

void loop(){

}

Result

As shown in the figure, the multimeter shows an output current of 10.05mA. The error is 0.05mA (0.5%), which is resulted from the accuracy of the multimeter and lack of calibration.