021-00 Digital DC Load

Digtial DC Load Project

key features:

• linear constant curren sink
• galvanic isolated
• selectable operating range (high/low current/voltage)
• controlled via I2C
  • write & read load current
  • read load voltage
  • read additional external voltage
  • read temperature
• manual option: set current via external voltage (or potentiometer)

example application:

• charge / discharge battery (control & measure current and voltage)
• measure & log current/voltage (use example setup to send data to PC)
• stess test of power supply

Repository Overview

• documentation
  • application notes for constant current sink
  • block diagram of PCB
  • screenshots and pictures of this project
• firmware
  • Arduino Example Project DigitalLoadExample, inlcuding a C++ class RL021_DigitalLoad for easy control
  • Example calibration procedure (manually step by step)
• hardware
  • KiCAD Project Folder including schematic, PCB layout and BOM
  • schematic and fabrication layer drawing as PDF
  • datasheet of used components
• ui
  • GUI_CSS is an example project for a simple pc-based user interface (written in processing)

Hardware

Order PCB: https://aisler.net/p/YHESFYKF

Jumper Settings

Via multiple jumpers the used operating ranges can be configured.

Example Setup

Example Arduino Control

Connect Arduino to CCS-PCB

Configure CCS-PCB according to your application

• See chapter "Jumper Settings" to select your operating range
• In the Arduino Code, the settings should be set according to physical state of the jumpers:

  	/// Write board jumper settings (like set on PCB)
  	myLoad.SetJumperSetting(JP2_CURRENT,Jumper_Closed);
  	myLoad.SetJumperSetting(JP3_VLOAD,Jumper_Open);
  	myLoad.SetJumperSetting(JP4_VEXT,Jumper_Open);  

Example User Interface

An example PC-based user interface (written in "Processing"), for the use with the firmware/DigitalLoadExample project.

Connect UI to Arduino

• The UI communicates via serial comport using simple ASCII character commands, so the communication could also be done manual.
• The UI uses the first found COMPORT (to use another port, change this in the processing code)

    String portName = Serial.list()[0];
    myPort = new Serial(this, portName, 115200);

Usage

In the "Control" page, all measured values are displayed in SI-units. The user can set the desired load current in mA.

In the "Calibration" page, the raw ADC values are displayed. The user can set the raw DAC value.

... find other projects: https://redlabs.de/