The B&K Precision MDL4UB Series is a multi-channel modular programmable DC electronic load system housed in a compact 4U form factor. A single MDL4U001 mainframe contains a built-in controller and four open module slots, and a connected MDL4U002 mainframe extension brings the system to eight slots and up to 4800 W of total sink power. Nine different load modules ranging from 200 W to 600 W can be combined in any arrangement to match the specific test bench, and dual-channel modules allow configurations of up to 16 load channels in a single system.

According to B&K Precision, the MDL4UB Series is designed to test a wide range of power sources, including multi-output DC power supplies, batteries, fuel cells, and photovoltaic arrays. Low minimum operating voltages — for example, 0.6 V at 20 A on the MDL4U102B and 1.8 V at 120 A on the MDL4U600B — make the modules suitable for fuel cell and solar cell test applications where the source voltage is inherently low. ATE and integration use cases are explicitly supported through standard LAN, GPIB, USB, and RS232 interfaces, included LabVIEW drivers, operating software for sequencing and data logging, and rack-mount brackets with handles.

ValueTronics International is an authorized B&K Precision distributor and stocks the MDL4UB Series at our 20,000 sq ft secure warehouse at 1675 Cambridge Drive, Elgin, Illinois. Equipment is received, inspected, and {{CONDITION}} units are performance-verified by our technicians before shipment. Holding inventory and performing testing in-house — rather than drop-shipping from a third-party warehouse — lets us confirm module configurations, mainframe compatibility, and accessory completeness on the same purchase order, and gives our Test Architects direct visibility into what is on the shelf when a customer asks about availability or a specific module combination.

Compare Other Models in This Series

The MDL4UB Series is structured as a mainframe-plus-modules system rather than a set of standalone instruments. The MDL4U001 mainframe houses the controller, front-panel function keys, numeric keypad, and four module slots, and the MDL4U002 mainframe extension adds four additional slots that operate under the connected mainframe's controller. Nine module variants — single-channel and dual-channel, 80 V and 600 V, and power ratings from 200 W to 600 W — populate those slots, and the comparison table below summarizes how those module variants differ.

Because mainframes and modules are ordered separately, the comparison focuses on the modules themselves: operating voltage range, rated current, rated power, and channel count. Customers selecting a configuration typically start with the highest voltage and current their device under test will present, confirm the power requirement at that operating point, and then choose between a single-channel module dedicated to one DUT or a dual-channel module that allocates total module power across two channels.

Each MDL4UB Series module and mainframe linked below is its own product page. new units are priced individually, and module-plus-mainframe configurations can be quoted as a combined order. Confirm the specific modules and mainframe you need with your Test Architect — including whether the configuration requires the MDL4U002 extension — so the quote reflects the complete system.

The most visible spec differences across the modules are operating voltage class and rated current. Five modules (MDL4U102B, MDL4U200B, MDL4U252B, MDL4U302B, MDL4U400B, MDL4U600B) are rated to 80 V, while the MDL4U305B, MDL4U502B, and MDL4U505B are 600 V modules for higher-voltage sources. Rated current ranges from 15 A on the MDL4U502B up to 120 A on the MDL4U600B, and rated power ranges from 200 W on the single-channel MDL4U200B to 600 W on the single-channel MDL4U600B.

Four modules — MDL4U102B, MDL4U252B, MDL4U302B, and MDL4U502B — are dual-channel designs in which total module power is allocated between the two channels. For example, B&K Precision states that the MDL4U102B can be configured as 150 W/50 W, 100 W/100 W, or 50 W/150 W across its two channels up to 200 W total. The remaining modules are single-channel. Minimum operating voltage at full-scale current also varies across the family, with the 80 V high-current modules reaching their rated current at voltages as low as 0.6 V to 1.8 V and the 600 V modules requiring higher minimums (for example, 4.5 V at 20 A on the MDL4U305B and 5.4 V at 30 A on the MDL4U505B).

Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below.

Accessories Supplied

• Certificate of calibration

Product Core & Specifications

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.