ALx Series DC Electronic Load

The ALx Series MagnaLOAD utilizes conventional linear MOSFET-based dissipative elements, allowing the series to achieve a very wide voltage-current operating range within the model’s maximum power rating. Using the same heat management innovations developed for Magna-Power’s high density programmable DC power supplies, the ALx Series’ conservative cooling ensures long product life with continuous full power operation in environments up to 50°C ambient operating temperature.

ALx Series DC Electronic Load Image
Power Levels
1.25 kW to 2.5 kW
Number of Models
Build Time
4 weeks
Design and Manufacture


MagnaLINK™ Distributed Digital Control

MagnaLINK Digital Control Image

Magna-Power’s MagnaLINK™ technology provides distributed Texas Instrument DSP control across power processing stages inside the MagnaLOAD DC electronic load. This technology follows a significant internal development cycle from Magna-Power to provide a unified digital control platform across its electronic loads and power supplies, featuring fully digital control loops, adjustable control gains, programmable slew rates, digital master-slaving, and many new advanced control technologies.

All ALx Series MagnaLOADs come with the following interfaces:

  • Front panel knob, keypad, and menu system
  • 25-pin configurable external user I/O, including a high-speed analog input
  • Front and rear USB and rear RS-485 or optional Ethernet and IEEE-4888 GPIB

When in standby or diagnostic fault, the DC input bus is disconnected via a switching device.

Finally, with a dedicated +5V interlock input pin and included +5V reference on all models, external emergency stop systems can be easily integrated using an external contact.

Flexible Operating Modes

To accommodate a variety of DC sources, all ALx Series MagnaLOADs come with many configurable control modes, including:

  • Voltage Mode
  • Current Mode
  • Power Mode
  • Resistance Mode
  • Shunt Regulator Mode
MagnaLOAD Control Modes

Preference for DC regulation is given to the parameter in the selected mode within the programmed set-points. Using the MagnaLOAD's set-points and trip settings, the product can configured to either trip with a fault when a limit is exceeded or to cross-over into a different regulation state.

Shunt Regulator Mode turns the MagnaLOAD into a high-speed smart braking resistor, engaging the DC input only when a specified voltage and exceeded by a user-defined percentage, while limiting the shunt current to a programmed set-point.

MagnaLOAD Control Modes

Digital Master-Slaving: Expandibility Without Compromise

All MagnaLOADs come standard with a MagnaLINK™ Input and a MagnaLINK™ Output port, which provides plug and play digital master-slaving. Simply connect the master's MagnaLINK™ Output to the slave's MagnaLINK™ Input and, using the MagnaWEB software, the products will automatically configure themselves for master-slave operation as a higher-power unit based on the populated ports. Buffered digital MagnaLINK™ connections means many MagnaLOADs can be daisy-chained in master-slave operation. Master-slave MagnaLOAD units will aggregate measurements to one display panel.

The internal MagnaLINK™ protocol was developed with expandability at the forefront. When configured for master-slave operation, the master controller takes control of all the slave's digital "targets." With this digital master-slaving strategy, it is completely transparent whether the unit is operating as a stand-alone product or in master-slave.

Configurable External User I/O

MagnaLOAD User I/O

Beyond the front panel and computer controls, all MagnaLOADs come standard with a 25-pin D-Sub connector designated as the External User I/O. This connector provides:

  • 8 Digital Outputs
  • 4 Digital Inputs
  • 4 Analog Outputs
  • 4 Analog Inputs

All the analog-digital I/O ports are configurable, allowing the user to select which parameters they want to control and monitor. This configurable I/O scheme reduces complexity, eases PLC integrationand allows control parameters from various interfaces simultaneously.

The MagnaLOAD's configurable analog inputs provide 0-10V programming from PLCs and external D/A converters.

MagnaWEB Software Interface

MagnaWEB Software

Magna-Power's next generation software interface, MagnaWEB, provides intuitive and user-friendly web-browser based controls for programming and measurement read-back of the MagnaLOAD's activity. Virtually all of the MagnaLOAD's available functions can be controlled and monitored from the MagnaWEB software over any of product's installed communication interfaces.

MagnaWEB uses a server-client software model to provide access to the MagnaLOAD from nearly any device and operating system. Install and run the MagnaWEB software locally on Windows then, using a web browser, access the server connected to the MagnaLOAD from a variety of devices including other desktops, tablets or smart-phones.

Extensive Programming Support

All ALx Series MagnaLOAD DC electronic loads come with a dedicated National Instruments LabVIEW™ driver, Interchangeable Virtual Instrument (IVI) driver, and support for a wide range of Standard Commands for Programmable Instrumentation (SCPI). These programming interfaces support full control, measurement, and monitoring of the MagnaLOAD. All of the MagnaLOAD's available communication interfaces are supported by these drivers and command sets, including: USB, RS-485, LXI TCP/IP Ethernet, and IEEE-488 GPIB.

Showcased in the following basic code examples, SCPI commands provide the simplest form of communication by using plain ASCII text and parameters sent over a basic socket connection. Over 40 commands are provided, with detailed documentation in the ALx Series User Manual.

Finally, Magna-Power's MagnaWEB software is provided allowing for web browser based control.

import visa
rm = visa.ResourceManager()
magna_power = rm.open_resource(USB::0x0403::0x6015::1201-2358::INSTR)
magna_power.write('VOLT 1000')
magna_power.write('CURR 20')
magna_power = visa('ni','USB::0x0403::0x6015::1201-2358::INSTR');
idn = fscanf(magna_power)
fprintf(magna-power,'VOLT 1000')
fprintf(magna-power,'CURR 20')
string resourceString = "USB::0x0403::0x6015::1201-2358::INSTR";
mbSession = (MessageBasedSession)ResourceManager.GetLocalManager().Open(resourceString);
string idn;
mbSession.Timeout = 3000;
idn = mbSession.Query("*IDN?");
mbSession.Write("VOLT 1000");
mbSession.Write("CURR 20");
MOSFET Electronic Load Technology

Wide Full-Power Operating Range

The ALx Series uses MOSFETs for power dissipation, delivering among the industry's widest full-power operating for its product class. The ALx Series uses MOSFETs operated in the linear region to allow full power and full control over the entire VA rating of the product.

MOSFETs are specifically selected based on their ability to operate in the linear region and have safe operating curves well below the maximum power rating when used as an electronic switch. Control circuitry for ALx Series MagnaLOADs are operated in a closed loop to linearize the response. Each MOSFET device produces a load current defined by VC/Rn. Closed loop amplifiers enable multiple MOSFETs to share load current equally.

Front Panel - Standard

MagnaLOAD Standard Front Panel

Front Panel - Blank Panel (+BP) Option

START: Enables the DC input bus
STOP: Disables the DC input bus
Voltage measurement display
Current measurement display
4-line character display featuring a menu system, operating status and modes, product messages with diagnostic codes, resistance measurement display, and power measurement display
Control power switch, energizes the control circuits without engaging DC bus
LED indicator that the DC input is enabled
Full control (host) front panel USB port
Clean air intake, with integrated fans
Aluminium digital encoder knob for programming set-points
LED indicator of the MagnaLOAD's present regulation state, which can include: constant voltage (CV), constant current (CC), constant power (CP), or constant resistance (CR)
Selector buttons to choose which set-point the digital encoder knob and digital keypad buttons will modify.
MENU: Enters the menu system on the 4-line display
BACK: Moves back one level in the menu
ENTER: Selects the highlighted menu item
CLEAR: Removes the product from a faulted state
LOCK: Locks the front panel, with password protection available
USA Flag

Designed and Manufactured in the USA, Available Worldwide

For complete control of quality, MagnaDC programmable DC power supplies are designed and manufactured at Magna-Power's vertically integrated USA manufacturing facility in Flemington, New Jersey. Heat-sinks and chassis are machined from aluminum. All sheet metal is fabricated and powder coated in-house. Magnetics are wound-to-order from validated designs based on a model's voltage and current. An automated surface-mount production line places components on printed circuit boards for control, driver, auxiliary power, and display circuits. And finally after assembly, products undergo comprehensive test and calibration, followed by an extended burn-in period.


There are 6 different models in the ALx Series spanning power levels: 1.25 kW, 2.5 kW.

Use the following ordering guide and models chart to define the best model for your application.

Model Maximum Power Maximum Voltage Maximum Current Package Type Minimum Voltage
ALx1.25-200-300 1.25 kW 200 Vdc 300 Adc Rack-mount 2.5 Vdc
ALx1.25-500-125 1.25 kW 500 Vdc 125 Adc Rack-mount 6.0 Vdc
ALx1.25-1000-37.5 1.25 kW 1000 Vdc 37.5 Adc Rack-mount 7.5 Vdc
ALx2.5-200-600 2.5 kW 200 Vdc 600 Adc Rack-mount 2.5 Vdc
ALx2.5-500-250 2.5 kW 500 Vdc 250 Adc Rack-mount 6.0 Vdc
ALx2.5-1000-75 2.5 kW 1000 Vdc 75 Adc Rack-mount 7.5 Vdc

Operating Profile

With its sole use of linear elements for heat dissipation, the ALx Series has the widest operating profile of the MagnaLOAD products. This operating profile figure applies to all ALx Series models, normalized about the model’s maximum voltage, current, and power ratings.

ALx Series MagnaLOAD Operating Profile


AC Input Specifications
AC Input Voltage
85-265 Vac
1Φ, 2-wire + ground
AC Input Current
1.8-0.7 Aac
AC Input Frequency
50-60 Hz
AC Input Isolation
±1500 Vac, maximum input voltage to ground
Programming Specifications
All Modes
16-bit, 0.0015%
Voltage: ±0.1% of full scale voltage rating
Current: ±0.2% of full scale current rating
Power: ±0.3% of full scale power rating
Resistance: ±0.3% of full scale resistance rating
Rise/Fall Time
Voltage Mode: 350 ms, 10% to 90% full scale voltage rating
Current Mode: 700 μs, 10% to 90% full scale current rating
Power Mode: 40 ms, 10% to 90% full scale power rating
Resistance Mode: 650 ms, 10% to 90% full scale resistance rating
Trip Settings Range
Over Voltage: 10% to 110% of full scale voltage rating
Under Voltage: 0% to 110% of full scale voltage rating
Over Current: 10% to 110% of full scale current rating
Over Power: 10% to 110% of full scale power rating
Connectivity Specifications
Communication Interfaces
USB Host (Front): Type B
USB Host (Rear): Type B
RS485 (Rear): RJ-45
MagnaLINK™: RJ-25 x 2
External User I/O: Standard, 25-pin D-sub Female
Communication Interfaces
LXI TCP/IP Ethernet (Rear): RJ-45
GPIB (Rear): IEEE-488
External User I/O Specifications
Digital Input Voltage
5 V
Digital Input Impedance
10 kΩ
Digital Monitoring Voltage
5 V, 32 mA capacity
Digital Reference Voltage
5V, 20 mA capacity
Analog Sampling Rate
2 kHz
Analog Programming Voltage
0-10 V
Analog Programming Resolution
12-bit, 0.025%
Analog Monitoring Voltage
0-10 V, 3 mA capacity
Analog Monitoring Impedance
0.005 Ω
Analog Monitoring Accuracy
0.05% of full scale
Analog Reference Voltage
10 V, 20 mA capacity
Physical Specifications
Size and Weight
1.25 kW Models
5.25” H x 19” W x 24” D (13.34 x 48.26 x 60.96 cm)
40 lbs (18.1 kg)
Size and Weight
2.5 kW Models
5.25” H x 19” W x 24” D (13.34 x 48.26 x 60.96 cm)
65 lbs (29.5 kg)
Environmental Specifications
Ambient Operating Temperature
0°C to 50°C
Storage Temperature
-25°C to +85°C
Relative humidity up to 95% non-condensing
Air Flow
Front air inlet, rear exhaust
Regulatory Compliance
Complies with European EMC Directive for test and measurement products
Complies with EN61010-1
CE Mark
RoHS Compliant


Front Panel
Rear Panel
Side Panel

Integrated Options Available


This option provides an integrated IEEE-488 GPIB communications port, allowing the product to be fully controlled and monitored using supported commands, as well as adding some additional interface specific commands.

LXI TCP/IP Ethernet

This option provides an integrated TCP/IP Ethernet communications port, allowing the product to be fully controlled and monitored using supported commands, as well as adding some additional interface specific commands.

Accessories Available

Name Item Description Docs
MagnaLINK-6 17888 6-ft MagnaLINK Cable N/A
MagnaLINK-12 17888 12-ft MagnaLINK Cable N/A
MID-M 17888 MagnaLINK Interface Device - Master N/A
MID-S 17888 MagnaLINK Interface Device - Slave N/A
CAB1: Cabinet and Integration 1 17883 12U Cabinet (32” H x 24” W x 31.5” D) with casters, fans, and product integration N/A
CAB2: Cabinet and Integration 2 17883 24U Cabinet (51.5” H x 24” W x 31.5” D) with casters, fans, and product integration N/A
CAB3: Cabinet and Integration 3 17883 30U Cabinet (67” H x 24” W x 31.5” D) with casters, fans, and product integration N/A
CAB4: Cabinet and Integration 4 17883 36U Cabinet (75” H x 24” W x 31.5” D) with casters, fans, and product integration N/A
CAB3x2: Cabinet and Integration 3x2 17883 60U Double Cabinet (67” H x 48” W x 31.5” D) with casters, fans, and product integration N/A
CAB4x2: Cabinet and Integration 4x2 17883 72U Double Cabinet (75” H x 48” W x 31.5” D) with casters, fans, and product integration N/A


White Papers

Electronic Loads — A New Generation

A technical paper on the various electronic load technologies and a technical overview of Magna-Power Electronics patented (US Patent 9,429,629) Active Resistance Technology.

Application Notes

How to Buy

In the USA and Canada, Magna-Power sells it products directly from the factory, with a North American network of technical representatives. Magna-Power products are available worldwide through direct sales offices and authorized distributors. Requests from this form will either be quoted directly or automatically routed to the appropriate sales partner for quote.


Magna-Power products are made-to-order with build-times that vary depending on the model's maximum power rating. The current build-time for the ALx Series is 4 weeks.

Sales Partners

In the USA and Canada, Magna-Power sells it products directly from the factory, with a nationwide network of technical representatives. Magna-Power products are available available worldwide through direct sales offices and authorized distributors. Requests from this form will either be quoted directly or automatically routed to the appropriate sales partner for quote.

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MagnaLOAD Requirement