DK 20 C420 B — LEM DC Current Transducer

Precision · Flexibility · Reliability | 5A/10A/20A Jumper Selectable | 4-20mA Standard Output

DK20C420B Product Overview

The DK 20 C420 B is a high-performance DC current transducer from LEM (Switzerland), belonging to the DK series C solid-core product family. Designed for industrial automation and power monitoring applications, it uses open-loop Hall effect technology to achieve non-invasive, high-accuracy measurement of DC currents and linearly converts them into a standard 4-20mA industrial signal. With more than 30 years of sensor development experience, LEM has made the DK 20 C420 B a trusted choice for automation engineers and system integrators worldwide.

Key Advantages — Why Choose the DK 20 C420 B

One Device, Multiple Ranges – Jumper-Selectable Currents

Supports three rated currents – 5A, 10A, 20A – easily switched via internal jumpers. No need to stock multiple sensors for different ranges. This significantly reduces inventory costs and management effort, meeting various 5A to 20A application needs with a single model.

Standard 4-20mA Output – Plug & Play

Provides a standard 4-20mA current signal, directly compatible with PLCs, DCSs, and all common industrial acquisition modules. 4mA corresponds to -20A, 12mA to 0A, and 20mA to +20A – an intuitive and clear signal mapping. No additional signal conditioning circuitry is required, enabling quick system integration and dramatically shortening deployment time.

1% Accuracy – Reliable and Precise Measurement

±1% accuracy and ±0.75% linearity ensure every measurement is trustworthy. In applications demanding high data fidelity – such as battery charge/discharge monitoring and power supply testing – the DK 20 C420 B delivers consistent, dependable results.

Galvanic Isolation – Double Safety Protection

With an isolation test voltage of 3kVrms / 50Hz / 1min, the transducer provides full galvanic isolation between primary and secondary circuits. Even in highvoltage, high-interference industrial environments, downstream equipment and personnel are protected. Compliant with UL94-V0 flammability rating.

Fast Response – Real-time Monitoring without Delay

Typical response time is < 20ms and the bandwidth covers DC. It captures instantaneous current changes with minimal delay, providing timely feedback for realtime monitoring and protection systems.

Wide Operating Temperature – Adapts to Harsh Environments

Operating temperature range from -20°C to +50°C. Whether installed in a cold outdoor electrical cabinet or a hot factory floor, the DK 20 C420 B runs stably and reliably.

Flexible Mounting – DIN Rail Support

Can be mounted on a standard DIN rail using an optional adapter, or panel-mounted – perfectly integrating into your electrical and control cabinets.

DK20C420B Core Parameters at a Glance

DK20C420B Application Scenarios

With its precision, flexibility, and reliability, the DK 20 C420 B is widely used in:

Renewable energy & energy storage – battery pack current monitoring, storage BMS, EV chargers, PV inverters, storage PCS

Power supply systems – general test power supplies, special power supplies, telecom power, server power, UPS

Industrial automation – DC motor monitoring, industrial power monitoring, PLC system integration

Renewable power generation – solar/wind power systems, fuel cell testing

Test & measurement – battery test systems, power semiconductor test, RF power supplies

Smart grid & distribution – distribution monitoring, storage fire protection systems

DK20C420B Technical Features in Detail

Openloop Hall effect technology
Uses LEM’s mature open-loop Hall effect measurement principle. No magnetic core saturation compensation circuits are required, resulting in a simple, highly reliable structure with excellent long-term stability.

Single-channel unidirectional measurement
Single-channel design optimised for unidirectional or bidirectional DC current measurement. The signal processing path is clean, providing strong immunity to interference.

19.1 mm busbar aperture
Generous opening allows easy pass-through of thick cables, making on-site wiring simple and fast.

Lightweight and compact design
Weighs only 120g and has a small footprint, enabling flexible placement even in space-limited electrical cabinets.