Tuesday, October 09, 2012

Automotive battery monitoring transducers from LEM offer improved resolution and offset errors

LEM has introduced the HAB xx-S family of current transducers for automotive battery-monitoring applications. These transducers have been designed to measure DC, AC, or pulsed currents up to ±100A. A new Application Specific Integrated Circuit (ASIC) incorporated into the units offers resolution 2.5 times better than previous models and a two-fold improvement in offset error, coupled with a significant reduction in price.

The transducers use open-loop, Hall-effect technology that simplifies both installation and servicing by removing the need to cut the [primary] cable carrying the measured current. They provide a pulse-width modulated (PWM) output signal proportional to the primary current being measured and operate from a unipolar 5V supply. Temperature measurement capability can be integrated with the addition of a fourth connection pin to the transducer package.

Output resolution of the HAB 60-S transducer is 0.03A with a linearity of 0.2%. Electric offset error is typically 0.075A across the temperature range from –10° to +65° C, and 0.15 A across the full range from –40° to +125° C.

A water-tight housing and sealed connector provide full environmental protection in enginecompartment applications.

Principal applications are expected to be in the measurement of battery-pack currents in electric, hybrid, and conventional vehicles. The transducers are fully certified to automotive standards.

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