The BK Precision MDL4U001 Mainframe for MDL DC Load Modules is a multi-channel modular programmable electronic load system. Seven different modules of programmable DC loads ranging in power from 200 W to 600 W provide users the flexibility to test a wide range of power sources from multi-output AC/DC power supplies to batteries, fuel cells, and photovoltaic arrays. The mainframe consists of a controller and four open slots that can be populated with any combination of modules up to 2400 W (up to 4800 W with mainframe extension, sold separately). The high-performance electronic load modules of the MDL4U Series are capable of operating in constant current (CC), constant voltage (CV), constant resistance (CR), constant power (CW), and constant impedance (CZ) mode, which uses DSP technology to simulate non-linear loads and realistic loading behavior. Easily edit the load's parameters such as voltage, current, slew rate, and width via the front panel. Increase productivity by saving your test parameters into any one of the 101 memory areas for quick system recall. Additionally, the MDL4U Series provides 16-bit resolution as well as numerous protection modes and a power-on system self-test to ensure the reliability of your testing. For remote communication, the MDL4U Series provides LAN, USB (USBTMC-compliant), RS232, and GPIB standard interfaces that support SCPI command protocol.

Equipped with a high-performance microprocessor in every mainframe and module, the MDL4U Series programmable DC electronic load utilizes a parallel architecture that provides high measurement speed. Additionally, a simultaneous load on/off operation can be performed through the front panel, analog control terminal, or remote SCPI command. This configuration allows the system to control modules synchronously and increases productivity in testing.

With the removable module design, you can choose suitable load modules to modify the system according to your requirements. This design allows for multiple channels and is ideal for testing several units, especially power supplies with multiple outputs. At the same time, all load modules can be configured to work independently. All load modules, including the high power 500 W and 600 W modules can fit in one slot. Unlike competitor models that require two slots for high power modules, the MDL4U Series offers a one-slot form factor for all modules.

Transient operation enables the module to periodically switch between two load levels. A power supply's regulation and transient characteristic can be evaluated by monitoring the supply's output voltage under varying combinations of load levels, duty cycle, and slew rate. The MDL4U Series can simulate these conditions up to 25 kHz.

In constant current mode, users can control the rate or slope of the change in current in a transient response test. Set the slew rate to as slow as 0.0001 A/μs or as fast as 2.5 A/μs depending on the module and selected current range.

Not limited to just switching between two levels, list mode lets you generate more complex sequences of input changes with several different levels. Up to 7 groups of list files can be saved in the mainframe. Each list can contain up to 84 steps with a minimum width time of 20 μs per step.