DC Electronic Load Programming

If you’re planning to control your Array DC Electronic Load (CSI3720A, CSI3721A, CSI3722A, or CSI3723A) through a computer this guide will help you get started. The DC Electronic Load can be programmed via RS-232 to acquire data from solar panels or wind turbines, discharge a battery at programmable values, or other testing purposes. First you will need to make sure you have the appropriate hardware to connect your computer’s USB to the RS-232 port on your device.  Because of DCE/DTE conflicts you will need both an RS-232 to USB adapter and a null modem, thankfully we have a compact solution that accomplishes all of this in one handy USB to Null Modem Serial Adapter Cable.  Once you’ve connected your cable and powered on your DC Electronic Load instrument you will need to follow these steps:

  • Open Windows Explorer > Control Panel > Hardware and Sound > Devices and Printers > Device Manager
  • Expand the Ports category
  • Right click the USB Serial Port > select Properties > Select Port Settings



  • Here you can ensure that the port settings match the settings on your Array Electronic Load (see DC Load manual for settings look up) Select advanced > from the COM Port Number assign it the lowest COM Port Number available (COM1 if available, if 1-4 are not available you may not be able to operate with certain software) > click OK


  • At this point you can open your instrument control software of choice (free options include SCPI Commander, Putty and paid options: Labview, Matlab)

Here we will include some examples from SCPI Commander:

Initial blank screen



Sending query *IDN? which puts the device in remote mode and provides the identification information


“CURR 0.5” sets the current limit level to 0.5 A


“INP ON” turns the input on to allow the DC Electronic Load to begin acquiring


“MEAS:CURR?” query returns the value of the current – here we’ve connected it to a 4.5V power supply in powered off and powered on positions


You can also write programs to collect data during battery discharge, acquire data from a solar panel (or other load), or measure rise times and performance of power supplies (as we often do).  Below are some samples of the data collected after running a a small multi-output power supply and a two 260W solar panels connected in parallel, each were connected to the CSI3721A pictured below.




PS-28 Testing



Hopefully you learned a bit more about the versatility of these DC Electronic Loads.  If you have specific programming needs feel free to contact us at services@circuitspecialists.com



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