The LRS-18 series of LVIT (Linear Variable Inductance Transducer) spring-loaded position sensors by Alliance Sensors Group are contactless devices designed for dimension or position measuring applications in factory automation and in various industrial and commercial applications, such as: automotive testing, mil/aero test stands, robotic arms, and packaging equipment. An ideal solution for when the sensing element cannot be attached to the object being measured. LRS-18s are offered in full scale ranges from 0.5 to 4.0 inches (12.5 to 100 mm) with excellent resolution and high stroke-to-length ratios. The maximum tip force on the item being measured is 1 pound.
LRS-18 sensors have a 0.75 inch (19 mm) diameter aluminum or stainless steel body with an M18 x 1 thread and come with two hex jam nuts for easy installation in place of an 18 mm analog prox sensor. These sensors use a 0.25 inch diameter probe equipped with an AGD No. 9 contact tip, and are offered with either an axial cable or a connector. Operating from a variety of DC voltages. These sensors are available with a choice of four analog outputs and they all include ASG’s proprietary SenSet™ field recalibration feature.
For more information see the technical datasheet below.
- - Spring-loaded LVIT Technology™ (Linear Variable Inductance Transducer)
- - Ranges from 0.5 to 4.0 Inches (12.5 to 100 mm)
- - Contactless Operation Prevents Internal Wearout from Dithering or Rapid Cycling
- - Excellent Stroke-to-Length Ratio
- - Proprietary SenSet™ Field Adjustable Range Scaling
| Analog I/Os: | 0 - 5 V or 0.5 - 4.5 V DC output with 8 - 30 V input, 35 mA max. 0 - 10 V DC output with 12 - 30 V input, 35 mA max. 4 - 20 mA (3-wire) output with 18 - 30 V input, 60 mA max. (75 C max.) |
| Measuring Ranges: | 12.5 mm to 100 mm (0.5 to 4.0 inches) full scale (nominal) |
| Linearity Error: | ±0.15% of Full Scale Output (FSO) typical, ±0.25% max. |
| Resolution: | 0.025% of FS |
| Operating Temperature: | -20 to 85 C (-40 to 105 C Extended Range) |
| Temperature Coefficient: | ≤±0.015% of FS/K |
| Vibration: | 5-20 Hz 0.5 inch p-p; 20-2000 Hz 4.2 g p-p |
| Shock: | 1000 g, 11 msec. |
| Terminations: | IEC IP-67 |
| Humidity: | 95% RH, non-condensing |
Position Sensor Terminations LRS-18
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LRS | X- | XX- | XXX- | X- | XX- | XX | X- |
| E- voltage | 18 - M18 | 013 (12.7 MM) | A- Axial | 00- 1 m cable | 05- 0.5 to 4.5 V DC | A- Aluminum |
| I- Current |
| 025 | 01- 5-pin M-12 | 06- 4.5 to 0.5 V DC | S- 300 Series SS | |
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| 050 |
| 02- 6-pin PT02 | 10- 0 to 10 V DC |
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| 075 |
| 03- 3 m cable | 11- 10 to 0 V DC |
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| 100 |
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| 20- 4 to 20 mA |
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| 21 - 20 to 4 mA |
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| 50 - 0 to 5 V DC |
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| 51 - 5 to 0 V DC |
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Wiring Table | ||
I/O Function | M12 Pin | Cable Color |
+24 V DC input | 1 | Red |
Ground | 2 | Black |
LRSE voltage output | 3 | Green |
LRSI current output | 4 | Green |
SenSet™ | 5 | White |
'A' Nominal Range | 'B' Body Length | Spring Rate | Max. Force |
inches [mm] | inches [mm] | Lbf/in [kgf/cm] | Lbf [kgf] |
0.5 [13] | 3.50 [88.9] | 0.75 [0.134] | 0.9 [0.41] |
1.0 [25] | 4.00 [101.6] | 0.75 [0.134] | 0.9 [0.41] |
2.0 [50] | 5.08 [129.0] | 0.43 [0.077] | 1.0 [0.45] |
3.0 [75] | 6.16 [156.5] | 0.30 [0.054] | 1.0 [0.45] |
4.0 [100] | 7.25 [184.1] | 0.23 [0.041] | 1.0 [0.45] |
If you are looking for CAD drawings of our LRS-18 sensor, simply call us at 856-727-0250 or use the online contact us form by clicking here.
Download LVIT Spring-Loaded Position Sensor LRS-18 DatasheetThe LRS-18 is a compact spring-loaded LVIT with a 19 mm OD housing and an industry-standard M18 threaded body. It offers the contact-following capability of an integrated return spring in a smaller, lower-cost package than larger spring-loaded sensors like the GHS-19 series. The M18 thread makes it a direct mechanical drop-in replacement for proximity sensors and potentiometers in automation fixtures and OEM mechanisms where space is tightly constrained. The spring-loaded mechanism also eliminates the need for external return springs in surface contact measurement applications.
Why Replace a Proximity Sensor or Potentiometer with the LRS-18?
Drop-In Replacement for 18 mm Threaded Sensors
Many industrial automation systems use 18 mm diameter proximity sensors or resistive potentiometers for position feedback. These devices have significant limitations: proximity sensors provide only discrete on/off switching, while potentiometers suffer from mechanical wear and signal degradation over time. The LRS-18's M18 threaded body fits directly into the existing mounting hardware designed for these sensors, allowing engineers to upgrade to continuous, contactless LVIT position measurement without modifying the mechanical installation.
This upgrade path is particularly valuable in quality control stations, automated assembly lines, and packaging equipment. In these settings, replacing a worn potentiometer with an LRS-18 eliminates the recurring maintenance cycle while adding higher-resolution, wear-free position data to the control system.
Contactless LVIT Sensing vs. Potentiometric Wear
Potentiometers rely on a resistive wiper that degrades with every cycle, introducing noise and signal dropout and eventually requiring replacement. The LRS-18's contactless LVIT sensing principle uses an inductive coil and spoiler with no physical contact between sensing elements. As a result, it delivers consistent output over millions of cycles without the maintenance intervals that potentiometers demand. In high-cycle applications like automated gauging or repetitive assembly verification, this translates directly into reduced downtime and lower total cost of ownership.
Compact Spring-Loaded Design for OEM Integration
Self-Contained Sensor with Integrated Return Spring
The LRS-18's self-contained design benefits OEM equipment designers who need a spring-loaded position sensor in a compact package. The sensing element, guide bearing, return spring, and signal conditioning electronics are all housed in the 19 mm OD body; the only external connections are the power supply and output wiring. This simplifies the OEM's mechanical design by eliminating the need to specify and source a separate return spring, and to mount it in a location that maintains correct spring force and alignment throughout the sensor's travel.
LRS-18 vs. GHS-19: When Does the Smaller Package Matter?
The GHS-19 is ASG's full-featured spring-loaded LVIT in a 19 mm housing. The LRS-18 provides comparable spring-loaded functionality at a lower price point, with an M18 threaded body that matches standard metric instrumentation cutouts. For applications where M18 thread compatibility, lower cost, or a more compact profile are priorities, the LRS-18 is the better fit. For applications requiring the GHS-19's extended stroke range or heavier spring force, the larger sensor remains the right choice.
Output Options and System Integration
DC-In/DC-Out with Standard Industrial Outputs
The LRS-18 provides the same DC-in/DC-out output options as the rest of the ASG LVIT family — ratiometric voltage, unipolar voltage, or 4–20 mA — and connects directly to a downstream instrument or PLC without external signal conditioning. This simplifies wiring and reduces system cost compared to AC-LVDT alternatives, which require a separate signal conditioner.
Typical Applications for the LRS-18
- Automated gauging and dimensional inspection stations
- OEM packaging, labeling, and assembly equipment
- Drop-in replacement for 18 mm proximity sensors and potentiometers
- Surface contact measurement with automatic return-to-zero
- Quality control fixtures in automotive and electronics manufacturing
SenSet™ Field Programmability
Like all ASG LVITs, the LRS-18 includes SenSet™ field programmability for zero and span adjustment at the point of installation. This allows engineers to match the sensor's full-scale output to the actual range of motion in the application, maximizing measurement resolution and eliminating the need for factory recalibration when the mechanical setup changes.
