How accurate is the LEM current sensor?

Accurate measurement of current is extremely important, in applications to ensure optimal equipment performance. Minor inaccuracies can cause issues. LEM, a known specialist, in electrical measurement technology provides a variety of sensors that are highly regarded for their precision and dependability. In this article we will delve into LEMs range of sensor products examine their applications and emphasize the significance of accuracy when it comes to measuring current.

Understanding the Importance of Accuracy

Precise and reliable current measurement plays a role, in industries such, as medical equipment, automotive battery management, power supplies and more. It is imperative to have measurements to ensure the systems performance and safety. LEMs current sensors are specifically designed to deliver measurements guaranteeing dependable operation and optimal performance.

Main Applications for LEM Current Sensors

There are some main applications for LEM Current Sensors:

Medical Equipment Accuracy

Accurate current measurement plays a role, in equipment particularly, in MRI scanners. The quality of the images produced by MRI scanners heavily relies on measurement. LEMs high precision sensors are utilized in MRI scanners and other medical equipment to ensure power control.

High-Precision Equipment Validation

LEM has established itself as a frontrunner, in the production of current sensors for testing industrial equipment. These sensors provide stability and precision measuring the magnitude down to parts, per million (PPMs). They are extensively utilized in calibration test benches and reputable laboratories.

Typical Applications for High Precision

LEM’s current sensors find applications in various fields, including:

  • Test & Measurement
  • Medical equipment (scanners, MRI, etc.)
  • Precision motor controllers
  • Metering
  • Power Analyzers

LEM Current Sensor Product Range

LEM offers a wide range of current sensors to cater to different application requirements. Let’s explore some of their product categories:

Current Sensors

LEM’s current sensors are available in different current ranges, ensuring accurate measurements for various industrial applications. The current ranges include:

  • 45-90 A
  • 90-180 A
  • 5-375 A
  • 375-750 A
  • 750-1500 A
  • 1500-3000 A
  • 3000-6000 A
  • 6000-12000 A
  • 12000-24000 A
  • Other value

Voltage Sensors

LEM also offers voltage sensors for precise voltage measurement. The voltage ranges include:

  • 25-50 V
  • 50-100 V
  • 100-200 V
  • 200-400 V
  • 400-800 V
  • 800-1600 V
  • 1600-3200 V
  • 3200-6400 V

Integrated Current Sensors

LEMs current sensors are designed to combine measurement and signal conditioning, into a single package. This integration allows for effortless integration, into systems while ensuring accurate measurements. LEM offers a range of sensor series to cater to different requirements.

  • GO Series
  • HMSR Series
  • FHS Series

Rogowski Coil

LEMs Rogowski coil sensors are specially crafted to provide measurement, in demanding scenarios. These sensors offer invasive solutions, for sensing current. The Rogowski coil series encompasses the following options:

  • ART Series
  • ARU Series

Energy Meters

LEM also provides energy meters for precise energy measurement in various applications. Some of the energy meter models include:

  • TEMA4G
  • EM4T II
  • DCBM 400 & 600
  • DCBM 100

Ensuring Accuracy and Reliability

LEM’s commitment to accuracy and reliability is reflected in their product features and certifications. Let’s explore some of the key aspects:

Compliance with Industry Standards

LEM ensures that their products and processes adhere to industry standards. They have obtained CE marking for compatibility and meet the safety and EMC standards set by IEC. LEM also prioritizes friendliness by being RoHS compliant. Additionally their production and development centers hold ISO TS 16949 certification.

Quality Products and Services

LEMs extensive understanding of applications and cutting edge measurement technologies enables them to create top notch products. They provide a range of options, including offerings and personalized solutions designed to meet needs, in terms of performance, space utilization and cost considerations.

Ensuring Accuracy at Different Current Levels

When it comes to sensors accuracy plays a role. LEM provides accuracy specifications in their datasheets, which help users understand the measurement errors, at levels of current.

For instance let’s consider LEMs HTFS 200 P sensor. The datasheet mentions the accuracy at Ipn (rated current). At 200A (Ipn) the accuracy is specified as 1% of Ipn, which translates to 2A. However it is important to consider the reading error for currents. Unfortunately explicit information about the reading error for currents is not provided in the datasheet.

In contrast Honeywells CSNF6661 datasheet mentions accuracy (0.5%) which implies that when measuring 200A the reading error amounts to 1A while for measuring 1A it is around 5mA.

To ensure current measurement across various levels of current it is advisable to refer to the datasheets and technical specifications offered by manufacturers like LEM and others. These documents provide insights into the accuracy and reliability of sensors, across different ranges of current.                                                                         

Power Supply Considerations for LEM Current Sensors

When working with sensors it’s crucial to take into account the power supply requirements to ensure precise and dependable measurements. Certain LEM current sensors, like the HTFS 200 P model need a power supply consisting of both +15V. 15v. It is advisable to have both the +15V and 15V supplies start simultaneously to minimize the risk of magnetization.

To achieve synchronized power supply startup it is recommended to employ a switching mode power supply (SMPS) that can provide both +15V and 15V concurrently. However available power supplies do not explicitly state the order in which their outputs come up.

In situations it may be necessary to use a circuit or additional components to ensure simultaneous startup of the +15V and 15V supplies. For control and synchronization purposes using a combination of switching and linear regulators can help reduce noise levels and enhance performance.

In case of a power failure. If the current sensor becomes magnetized it is important to have a demagnetization mechanism, in place. LEM might offer application notes or guidelines on how to demagnetize their sensors. It is essential to follow their recommended procedures in order to restore measurements after any magnetization event.


LEM current sensors provide reliable solutions, for measuring current in a range of industrial applications. With their commitment to quality and adherence, to industry standards LEM is a trusted provider of sensors. By selecting LEMs sensors and taking into account power supply needs users can achieve measurements and optimize the performance of their applications.

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