Electronic Load

Control electronic load nets

Control electronic loads to sink current in various modes for testing power systems.

Import

from lager import Net, NetType

Methods

The Net-based API provides methods that can either get or set values. When called without a value parameter, methods read and return the current value. When called with a value, they set it.

Method	Description
mode(mode_type)	Set or read operation mode (CC/CV/CR/CW)
current(value)	Set or read constant current (A)
voltage(value)	Set or read constant voltage (V)
resistance(value)	Set or read constant resistance (ohms)
power(value)	Set or read constant power (W)
enable()	Enable electronic load input
disable()	Disable electronic load input
print_state()	Print comprehensive state
measured_voltage()	Read measured voltage (returns float)
measured_current()	Read measured current (returns float)
measured_power()	Read measured power (returns float)

Method Reference

Net.get(name, type=NetType.ELoad)

Get an electronic load net by name.

from lager import Net, NetType

eload = Net.get('LOAD', type=NetType.ELoad)

Parameters:

Parameter	Type	Description
name	str	Name of the electronic load net
type	NetType	Must be NetType.ELoad

Returns: Electronic load Net instance

mode(mode_type=None)

Set or read the operation mode.

# Set mode
eload.mode('CC')  # Constant Current
eload.mode('CV')  # Constant Voltage
eload.mode('CR')  # Constant Resistance
eload.mode('CW')  # Constant Power (also 'CP')

# Read current mode
current_mode = eload.mode()
print(f"Mode: {current_mode}")

Parameters:

Parameter	Type	Description
mode_type	str or None	’CC’, ‘CV’, ‘CR’, or ‘CW’/‘CP’. If None, reads current mode.

Returns: Current mode string if mode_type is None

current(value=None)

Set or read the constant current setting.

# Set CC mode current
eload.mode('CC')
eload.current(0.5)  # Set to 500mA

# Read current setting
i = eload.current()
print(f"Current setting: {i}A")

Parameters:

Parameter	Type	Description
value	float or None	Current in amps. If None, reads current setting.

Returns: Current setting in amps if value is None

voltage(value=None)

Set or read the constant voltage setting.

# Set CV mode voltage
eload.mode('CV')
eload.voltage(5.0)  # Set to 5V

# Read voltage setting
v = eload.voltage()
print(f"Voltage setting: {v}V")

resistance(value=None)

Set or read the constant resistance setting. Values below 0.02 ohms are at the minimum range limit of the instrument and may be clamped. A warning is printed if the applied value differs from the requested value.

# Set CR mode resistance
eload.mode('CR')
eload.resistance(100.0)  # Set to 100 ohms

# Read resistance setting
r = eload.resistance()
print(f"Resistance setting: {r} ohms")

power(value=None)

Set or read the constant power setting.

# Set CW mode power
eload.mode('CW')
eload.power(5.0)  # Set to 5W

# Read power setting
p = eload.power()
print(f"Power setting: {p}W")

enable() / disable()

Enable or disable the electronic load input.

eload.enable()   # Start sinking current
eload.disable()  # Stop sinking current

print_state()

Print comprehensive electronic load state.

eload.print_state()
# Prints: mode, current/voltage/resistance/power settings, measured values, input state

measured_voltage() / measured_current() / measured_power()

Read actual measured values (return floats, for use in code).

v = eload.measured_voltage()  # Returns measured voltage
i = eload.measured_current()  # Returns measured current
p = eload.measured_power()    # Returns measured power

print(f"V={v:.2f}V, I={i:.3f}A, P={p:.3f}W")

Returns: float - Measured value

Load Modes

Mode	Code	Description
Constant Current	CC	Sinks a fixed current regardless of voltage
Constant Voltage	CV	Maintains a fixed voltage across the load
Constant Resistance	CR	Behaves as a fixed resistance
Constant Power	CW or CP	Dissipates a fixed power

Examples

Constant Current Test

from lager import Net, NetType

eload = Net.get('LOAD', type=NetType.ELoad)

# Configure constant current mode at 500mA
eload.mode('CC')
eload.current(0.5)

eload.enable()

# Read measurements
print(f"Voltage: {eload.measured_voltage():.2f}V")
print(f"Current: {eload.measured_current():.3f}A")
print(f"Power: {eload.measured_power():.3f}W")

eload.disable()

Battery Discharge Test

from lager import Net, NetType
import time

eload = Net.get('LOAD', type=NetType.ELoad)

# Configure constant resistance load
eload.mode('CR')
eload.resistance(10.0)

eload.enable()

# Monitor discharge
for i in range(30):
    v = eload.measured_voltage()
    i_curr = eload.measured_current()
    print(f"V={v:.2f}V, I={i_curr:.3f}A")

    if v < 3.0:
        print("Discharge cutoff reached")
        break

    time.sleep(1)

eload.disable()

Power Efficiency Test

from lager import Net, NetType

# Input power supply
psu = Net.get('INPUT', type=NetType.PowerSupply)
psu.voltage(12.0)
psu.current(2.0)
psu.enable()

# Output load
eload = Net.get('OUTPUT', type=NetType.ELoad)
eload.mode('CC')
eload.current(0.5)
eload.enable()

# Measure efficiency
p_in = 12.0 * psu.measured_current()  # Input power
p_out = eload.measured_power()         # Output power
efficiency = (p_out / p_in) * 100 if p_in > 0 else 0

print(f"Input: {p_in:.2f}W")
print(f"Output: {p_out:.2f}W")
print(f"Efficiency: {efficiency:.1f}%")

eload.disable()
psu.disable()

Supported Hardware

Manufacturer	Model	Features
Rigol	DL3021 (DL3000 series)	CC/CV/CR/CP modes

Notes

• Use mode() to set the operation mode before setting the corresponding value
• Methods like current(), voltage(), resistance(), power() can get or set values
• measured_voltage(), measured_current(), measured_power() return actual measurements
• print_state() prints state (for debugging), measurement methods return values (for code)
• Always call enable() to start sinking current
• Always call disable() when finished
• Resistance values below 0.02 ohms may be clamped by the instrument