Electronic Load

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 the state to the box’s hardware-service log; returns `None`
`get_state_dict()`	Read the full state; returns a dict
`get_input_state()`	Read whether the input is on (returns bool)
`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 the instrument can clamp them. It prints a warning to the box’s hardware-service log when 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. The text goes to the box’s hardware-service log, not to your script, and the call returns None. In a script, use get_state_dict(). See #845.

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

`get_state_dict()`

Return the full electronic load state as a dict.

state = eload.get_state_dict()
print(state['mode'], state['measured_current'], state['input_enabled'])

Key	Description
`mode`	`CC`, `CV`, `CR` or `CW`
`input_enabled`	`True`, `False`, or `None` for an unrecognized reply
`measured_voltage`, `measured_current`, `measured_power`	Measured values
`current_setting`, `voltage_setting`, `resistance_setting`, `power_setting`	The setting for the active mode only

`get_input_state()`

Return True when the input is on. An unrecognized reply reads as False.

if eload.get_input_state():
    print("Load is on")

`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.set_voltage(12.0)
psu.set_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 = psu.power()                     # 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 to the box’s hardware-service log; get_state_dict() and the measurement methods return values (for code)
Always call enable() to start sinking current
Always call disable() when finished
The instrument can clamp resistance values below 0.02 ohms

Getting Started

Development

Power & Simulation

Measurement

I/O & Communication

Utilities

Electronic Load

Import

Methods

Method Reference

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

`mode(mode_type=None)`

`current(value=None)`

`voltage(value=None)`

`resistance(value=None)`

`power(value=None)`

`enable()` / `disable()`

`print_state()`

`get_state_dict()`

`get_input_state()`

`measured_voltage()` / `measured_current()` / `measured_power()`

Load Modes

Examples

Constant Current Test

Battery Discharge Test

Power Efficiency Test

Supported Hardware

Notes

​Import

​Methods

​Method Reference

​Net.get(name, type=NetType.ELoad)

​mode(mode_type=None)

​current(value=None)

​voltage(value=None)

​resistance(value=None)

​power(value=None)

​enable() / disable()

​print_state()

​get_state_dict()

​get_input_state()

​measured_voltage() / measured_current() / measured_power()

​Load Modes

​Examples

​Constant Current Test

​Battery Discharge Test

​Power Efficiency Test

​Supported Hardware

​Notes

Import

Methods

Method Reference

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

`mode(mode_type=None)`

`current(value=None)`

`voltage(value=None)`

`resistance(value=None)`

`power(value=None)`

`enable()` / `disable()`

`print_state()`

`get_state_dict()`

`get_input_state()`

`measured_voltage()` / `measured_current()` / `measured_power()`

Load Modes

Examples

Constant Current Test

Battery Discharge Test

Power Efficiency Test

Supported Hardware

Notes