The Sorensen MML-4 is a modular DC electronic load mainframe engineered for programmable load simulation across research, design validation, and manufacturing test environments. The system accepts plug-in load modules—up to four single-bay units or a combination totaling four bays—each optically isolated and floating to enable independent test channels. Individual modules operate in Constant Current (CC), Constant Resistance (CR), and Constant Voltage (CV) modes, supporting voltage ratings to 80V or 500V and current ranges from 1A to 120A depending on module selection. Power ratings span 100W, 300W, and 600W configurations. The mainframe draws 115/230 VAC switchable (or 100/200 VAC) at 5A/250V fuse rating and dissipates up to 180 VA maximum across the 47–63 Hz input band.
Technical Specifications
Mainframe
• AC input: 115/230 VAC switchable or 100/200 VAC switchable
• Input frequency: 47–63 Hz
• Maximum VA: 180 VA
• Module slots: Four single-bay or mixed single/double-bay configurations (up to 4 bays total)
• Dimensions: 440 mm W × 177.4 mm H (excluding feet) / 186 mm H (including feet) × 560 mm D
• Weight: 24 kg
• Operating temperature: 0–40°C
Load Modules
• Voltage range: Up to 80V or 500V maximum (module dependent)
• Current range: 0–1A, 0–2A, 0–6A, 0–10A, 0–20A, 0–60A, 0–120A (module dependent; programmable in two ranges)
• Power ratings: 100W × 2 (dual input, 80V only), 300W, 600W
• A/D converter: 15-bit resolution for real-time voltage and current measurement
• Current measurement resolution: 0.25 mA, 0.5 mA, 1.5 mA, 2.5 mA, 5 mA, 15 mA, 30 mA (examples)
• Voltage measurement resolution: 4 mV, 16 mV, 20 mV, 125 mV (examples)
• Dynamic loading: Programmable slew rates up to 5 A/µs; frequency to 20 kHz
• Minimum input resistance: Capable of sinking high current at voltages down to 1V
• Temperature coefficient: Typical 100 ppm
• Current accuracy: ±(0.1% + 0.1% F.S.), ±(0.1% + 0.2% F.S.), or ±0.4% F.S. (module dependent)
• Voltage accuracy: ±(0.05% + 0.1% F.S.) or ±(0.05% + 0.05% F.S.) (module dependent)
– Key Features
• Four optically isolated, floating load channels
• Front panel keypad and analog knob control
• RS-232 standard interface; IEEE-488.2 optional
• Rackmount (19-inch) and benchtop configurations
• Modular plug-in architecture for voltage, current, and power flexibility
– Typical Applications
AC/DC converter testing, DC/DC converter validation, power storage device characterization, and electronic component load simulation.
– Compatibility & Integration
RS-232 control standard; IEEE-488.2 available as option. Module power supplied from mainframe; each load module is independently floating.
