Instrument Basics: Electronic Loads -- Workbench Wednesdays 14

Instrument Basics: Electronic Loads

element14 Presents | Bald Engineer: James Lewis' VCP Profile | Workbench Wednesdays

An Electronic load can sink current from power sources such as power supplies or batteries. Loads are useful to test a power supply’s design margin or verify a battery’s capacity. See how three different instrument options from ultra low-end to midrange to high-end compare. Learn how modes like constant current and constant resistance can be used for different measurements.

Supplemental Material:

Bill of Material:

Product Name	Manufacturer	Quantity	Buy KitBuy Kit
Raspberry Pi 4	Raspberry Pi	1	Buy NowBuy Now
TMC2208 SILENTSTEPSTICK	Trinamic/Watterott	2	Buy NowBuy Now
SANYO DENKI Stepper Motor, Bipolar, 0.24 N-m, 1 A, Two Phase, 7.3 ohm, 5 mH	Sanyo Denki	2	Buy NowBuy Now
PRO SIGNAL Audio / Video Cable Assembly, HDMI A Plug to Micro HDMI D Plug, 6.6 ft, 2 m, Black	Pro Signal	2	Buy NowBuy Now
CLIFF ELECTRONIC COMPONENTS HDMI Audio / Video Adaptor, HDMI Receptacle, HDMI Receptacle, FT Series	CLIFF	2	Buy NowBuy Now
VERBATIM 3D Printer Filament, 1.75mm, PLA, Silver	Verbatim	1	Buy NowBuy Now
official MAYER MOVES PSU: XP POWER AC/DC Power Supply, ITE, 2 Output, 60 W, 5 V, 7 A, 12 V, 3 A	XP Power	1	Buy NowBuy Now

Attachments:

dc_electronic_load_application_note.pdf

Top Comments

genewu over 3 years ago

Really appreciate your reply!
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel

baldengineer over 3 years ago in reply to genewu

Here's the script I used on the NGM202:

import visa
import time

# exepcted resource string:
default_resource = "TCPIP0::192.168.1.176::inst0::INSTR"

def connect_to_inst():
    found = 0
    counter = 0
    for resource in resources:
        counter = counter + 1
        print(str(counter) + "] " + resource, end="")
        if (resource == default_resource):
            found = 1
            print(" <-- Using this one")
        else:
            print("")
    return found

def set_resistance(r):
    inst.write("SOURce:RESistance " + str(r))
    print("Resistance is now: " + inst.query("RES?"))
    # add error handling later
    return

# create the manager
print("Checking available resources:")
rm = visa.ResourceManager()
resources = rm.list_resources()

# check if the resource is available
if (connect_to_inst() == 0):
    print("Resource not found, exiting.")
    rm.close()
    exit()

# open the instrument
print("Opening instrument...")
inst = rm.open_resource(default_resource)
print(inst.query("*IDN?"))

# change resistance
inst.write("INST OUT2") # select the channel
inst.write("SOURce:CURRent 3")
print("Current limit is now: " + inst.query("CURR?"))

for index in range(100):
    print(index)
    set_resistance(100)
    time.sleep(0.6)
    set_resistance(10)
    time.sleep(0.3)
    set_resistance(50)
    time.sleep(0.1)
    set_resistance(5)
    time.sleep(0.1)

print("Closing resource...")
rm.close()

You'll need PyVISA installed, a Visa driver, and to change the IP address.

genewu over 3 years ago

Hi, Worth watching!
By the way, Can I have a link for python code you mentioned in the video?
Thank you.
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel
evanc over 5 years ago

Thanks for a very nice job explaining electronic loads.
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel
three-phase over 5 years ago

Nice clear demonstration of the basic functionality of an electronic load. Thanks for posting.

Kind regards.
- Cancel
- Vote Up +1 Vote Down
- Sign in to reply
- More
- Cancel
DAB over 5 years ago

Nice overview.

DAB
- Cancel
- Vote Up +1 Vote Down
- Sign in to reply
- More
- Cancel
koudelad over 5 years ago

Thank you for this introduction to electronic loads, baldengineer

I never really used one for my hobby purposes, but the battery simulation on R&S load looks great.
- Cancel
- Vote Up +1 Vote Down
- Sign in to reply
- More
- Cancel