The LA-21-A series AC LVDTs offers the robust designs for which Alliance Sensors Group is known in typical industrial packages, with full ranges from 3 inches (75 mm) to 15 inches (375 mm). They are supplied in a zinc-plated steel 0.805 inch (20.5 mm) diameter housing with 4-inch (100 mm) stripped-and-tinned axial leads. Each LVDT’s core is enclosed in a 3/8 inch (9.5 mm) diameter extension rod from which it cannot break loose and has a 5/16-24 UNF or M8 X 1.25 male thread for easy attachment.
LA-21-A AC-LVDTs are ideal for stamping or drawing press die opening, injection molding machine platen position, process valve controls, and roller gap feedback in steel or aluminum mills. Mated with ASG’s SC-200 industrial LVDT DIN-rail-mountable analog output signal conditioner, and LA-21-A LVDT becomes an ideal solution for typical industrial applications requiring rugged, accurate position sensors.
- - Mildly Radiation Resistant
- - Stock Ranges from 3 Inches to 15 Inches (75 mm to 375 mm) Full Scale
- - Core Totally Enclosed in 3/8 Inch (9.5 mm) Diameter Core Extension Rod
- - Environmentally Sealed to IP-68
| Available Full Ranges: | 0 to 3, 6, 9, 12, or 15 inches (0 to 75, 150, 225, 300, and 375 mm) |
| Excitation Frequency: | 3 kHz nominal |
| Excitation Voltage: | 3.0 V ACrms (nominal) |
| Full Scale Output: | 0.83 ±10% V ACrms output (nom.) from differentially connected (S1-S2) secondaries (ref: 3 Vrms excitation); sum of secondaries output is constant over range for ratiometric (S1-S2)/(S1+S2) operation |
| Linearity Error: | ≤±0.5% of FSO |
| Operating Temperature: | -40 to 175 C (-40 to 350°F) |
| Temperature Coefficient: | ≤±0.025% FSO/degree K |
| Humidity: | 95% RH non-condensing |
| Shock: | 1000 g, 11 msec. |
| Vibration: | 5-20 Hz 0.5 inch p-p; 20-2000 Hz 4.2 g p-p |
Series | Range inches | Termination |
LA-21-A- | XX- | XX |
03 - 3" | 04 - 4" leads | |
06 - 6" | ||
09 - 9" | ||
12 - 12" | ||
15 - 15" |
If you are looking for CAD drawings of our LA-21-A sensor, simply call us at 856-727-0250 or use the online contact us form by clicking here.
How the 21mm Form Factor Delivers Superior Durability in Demanding Applications
The LA-21 Series AC-LVDT position sensor bridges the gap between compact sensors and heavy-duty industrial requirements, offering a robust 21mm diameter housing that provides enhanced durability without excessive bulk. This optimized size delivers superior mechanical strength, improved thermal management, and extended stroke capabilities while maintaining compatibility with standard industrial mounting configurations. Manufacturing engineers specify the LA-21 Series when applications demand more robustness than smaller sensors provide but space constraints prohibit larger alternatives.
The 21mm diameter represents a carefully engineered sweet spot in sensor design. The increased cross-sectional area compared to 19mm sensors allows thicker housing walls, and more substantial internal components. These dimensional advantages translate directly to improved reliability in high-vibration environments, better resistance to side loading, and extended service life in continuous-duty applications.
Mechanical Advantages of the 21mm Platform
Understanding why the LA-21 Series excels requires examining how the 21mm form factor enhances fundamental design elements. The robust housing permits high reliability in harsh environments.
Enhanced Stroke Length Capabilities
The 21mm platform enables extended stroke lengths impractical in smaller designs. Available measurements to 1000mm maintain excellent linearity. This capability proves invaluable in large machinery, civil engineering structures, and process equipment requiring long-range position feedback.
Industrial Applications Leveraging LA-21 Advantages
Steel manufacturing particularly benefits from the LA-21 Series' robust construction. In continuous casting operations, these sensors monitor roller positioning in extreme heat, vibration, and contamination. The mechanical durability survives years of 24/7 operation while maintaining accuracy essential for product quality and equipment protection.
Mobile hydraulic equipment represents another primary application area. Excavators, cranes, and mining equipment subject sensors to severe shock, vibration, and environmental exposure. The LA-21 Series' combination of pressure rating, mechanical strength, and environmental sealing meets these challenges while providing feedback essential for precise control and safety systems.
Installation Best Practices for Industrial Environments
Successful LA-21 implementation requires attention to mounting rigidity and alignment. The sensor's enhanced capabilities only deliver value when properly installed. Using substantial mounting brackets prevents resonance amplification in high-vibration applications.
Cable management proves especially important given the LA-21's typical installation in heavy machinery. Armored cables protect against mechanical damage from moving equipment parts. Proper strain relief prevents work hardening at connection points. These installation details determine whether sensors achieve their 20-year design life or fail prematurely from preventable causes.
Connector Selection for Reliability
Industrial environments demand robust electrical connections. The LA-21 Series accommodates various connector types from MS military specifications to premium stainless steel designs. Selecting appropriate connectors based on environmental exposure and maintenance requirements prevents the majority of field failures.
Environmental sealing at the connector interface deserves special attention. While the sensor body achieves IP68 protection, improper connector sealing creates vulnerability. Potted connections or environmental splice kits ensure protection continuity throughout the measurement system. This attention to system-level protection distinguishes successful installations from problematic ones.
Predictive Maintenance Through Continuous Monitoring
The LA-21 Series' robust signal output enables sophisticated condition monitoring beyond simple position measurement. Signal quality analysis reveals developing mechanical issues before they impact measurement accuracy. Increasing noise levels indicate bearing wear, while DC offset changes suggest contamination ingress.
Implementing continuous monitoring requires minimal additional hardware. Modern PLCs include signal analysis capabilities that track sensor health parameters. Establishing baseline performance during commissioning provides comparison data for trend analysis. This proactive approach transforms position sensors from simple feedback devices to diagnostic tools preventing unexpected failures.
Integration with IIoT Platforms
Industrial Internet of Things (IIoT) initiatives leverage sensor data for comprehensive equipment monitoring. The LA-21 Series' analog outputs integrate easily with PLCs, enabling cloud-based analytics and remote monitoring. This connectivity supports predictive maintenance programs spanning entire facilities or equipment fleets.
Real-time alerts based on sensor performance degradation enable intervention before failures impact production. Maintenance teams receive notifications of developing issues with sufficient lead time for planned repairs. This capability proves especially valuable for remote or unmanned equipment where regular inspection isn't practical.
Total Value Proposition for Industrial Applications
The LA-21 Series demonstrates value through reduced total ownership costs despite higher initial investment than other sensors. Extended service life in harsh conditions, reduced calibration requirements, and predictive maintenance capabilities combine to lower lifecycle expenses. Standardizing on the robust LA-21 platform simplifies spare parts inventory while ensuring consistent performance across diverse applications.
The LA-21 Series AC-LVDT position sensor represents the optimal balance of size, durability, and performance for demanding industrial applications. Its 21mm form factor provides tangible advantages in mechanical strength, thermal stability, and measurement range while maintaining practical installation dimensions. Engineers seeking maximum reliability in harsh industrial environments consistently choose the LA-21 Series for its proven ability to deliver accurate position feedback year after year in conditions that destroy lesser sensors.
Download AC-LVDT Position Sensor LA-21-A Datasheet
