Bruel-Kjaer IN-081 Non-Contact Displacement Sensor

The Bruel-Kjaer IN-081 Non-Contact Displacement Sensor is a precision-engineered industrial sensor designed for accurate measurement of displacement without physical contact. Featuring a continuous thread with an integrated oscillator, this sensor is built for reliable operation in demanding industrial environments.

This model, order code IN-081/4/070/50/0/205, has a sensor length of 70 mm and a cable length of 5 meters, providing flexibility for installation in various machinery and equipment layouts. The Bruel-Kjaer IN-081 Non-Contact Displacement Sensor uses the G 3/8″-24 UNF-2A thread specification, allowing secure and standardized mounting. Its robust construction ensures stable performance even under high vibration, dust, and temperature fluctuations.

Non-contact sensing technology offers significant advantages over traditional contact-based sensors. By avoiding direct contact with the measured surface, the Bruel-Kjaer IN-081 Non-Contact Displacement Sensor reduces mechanical wear and extends operational life. This makes it ideal for continuous monitoring in predictive maintenance applications, where early detection of misalignments, wear, or displacement changes can prevent costly downtime.

The integrated oscillator enables stable signal generation and high measurement accuracy, ensuring consistent readings even in challenging industrial conditions. This sensor can be integrated seamlessly into existing monitoring systems, making it suitable for applications in power generation, oil and gas, marine, manufacturing, and other sectors requiring precise displacement measurement.

With its 5-meter cable length and no additional cable protection, the IN-081 offers installation versatility while minimizing unnecessary weight or complexity. Its compact design makes it suitable for areas with limited space, while its durable housing protects against environmental stressors.

Operators and maintenance teams rely on the Bruel-Kjaer IN-081 Non-Contact Displacement Sensor for dependable performance, accurate data collection, and compatibility with advanced condition monitoring systems. Whether for shaft position monitoring, structural displacement measurement, or high-speed machine analysis, this sensor delivers the precision and reliability that Bruel-Kjaer products are known for.

By implementing the Bruel-Kjaer IN-081 in your monitoring setup, you enhance operational safety, extend machinery lifespan, and improve maintenance efficiency, making it a valuable investment for any industrial facility.

Technical Specifications

The Brüel & Kjær Vibro IN-081 is a non-contacting eddy-current displacement sensor from the IN-08x family, distinguished by having its oscillator/driver electronics built directly into the sensor body rather than requiring a separate oscillator unit — simplifying the measuring chain compared with sensor families like the SD-16x that need a matched external oscillator. It provides a calibrated linear measurement range of 1.5mm, a frequency response of 0–2600Hz, and a sensitivity of -8mV/mm calibrated against 42CrMo4 steel target material. The sensor operates from an -18 to -30V DC supply and is rated for 0°C to +110°C operation.

Mechanically, the IN-081 features an adjustable thread length of 70–250mm with a full-length threaded probe body, giving installation flexibility across different casing thicknesses without needing a separate part number for every mounting depth. This base IN-081 configuration is not rated for hazardous (ATEX/IECEx) area installation — a separate “INA-08x” variant exists for that purpose.

Standards and Applications

The IN-08x family complies with the accuracy requirements of API 670 and DIN 45670, the industry-standard specifications for machinery-protection transducer performance. It is used for relative shaft vibration, relative shaft displacement (radial and thrust position), and rotor speed measurement on rotating machinery such as turbines, compressors, and pumps — typically feeding a VIBROCONTROL 6000 or similar protection and condition-monitoring rack.

Why Seven Star LLC

Seven Star LLC supplies genuine Brüel & Kjær Vibro eddy-current displacement sensors, including the IN-081, to power generation, oil & gas, and petrochemical customers across Oman and the wider GCC, and confirms the exact probe length and installation configuration required to match the customer’s existing machine before confirming an order.

Integrated vs Separate Oscillator Design

Building the oscillator/driver electronics directly into the IN-081’s sensor body reduces the number of separately certified components in the measuring chain and simplifies spares management, since a maintenance team only needs to stock and match one part rather than a sensor plus a separate oscillator unit matched to it. The tradeoff is that if the electronics inside the sensor fail, the entire sensor assembly must be replaced rather than swapping only the oscillator — a design consideration worth weighing against the SD-16x/OD-16x separate-oscillator architecture when planning spares strategy for a new installation.

Target Material and Calibration

Eddy-current displacement sensors are calibrated against a specific target material — in this case 42CrMo4 shaft steel — because the eddy currents induced in the target, and therefore the sensor’s output voltage per unit of gap, depend on the target’s electrical conductivity and magnetic permeability. Installing the IN-081 against a shaft made from a significantly different alloy without accounting for the material difference will introduce a calibration offset, so Seven Star LLC confirms the customer’s actual shaft material before quoting to flag any recalibration or correction factor the installation may need.

Ordering Notes

Because the IN-08x family spans multiple probe lengths and both hazardous and non-hazardous area variants (IN-08x vs INA-08x), Seven Star LLC confirms the exact machine casing thickness and area classification before quoting, ensuring the correct variant is supplied rather than assuming one configuration fits every installation, which is exactly where a mismatched spare causes the most delay.

Request a Quote for Bruel-Kjaer -IN-081

Submit a formal inquiry through our RFQ page with your required probe length and monitoring system compatibility. We will confirm the correct IN-081 configuration and provide a formal quotation.

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