AC-LVDT Position Sensor LA-20.6 Series

The LA-20.6 is a heavy-duty AC-LVDT with a 0.812-inch (20.6 mm) OD housing that occupies a deliberate middle position in the LA series lineup. Its housing provides slightly more winding space — and therefore higher output sensitivity — than the 19 mm series, while remaining compact enough for installations where the larger LA-25 will not fit. For engineers working within tight mechanical envelopes who still need strong signal output, the LA-20.6 fills a gap that would otherwise force a compromise between size and sensitivity.

The sensor's core bore diameter and mechanical interface are compatible with the broader LA series accessory ecosystem. The same end fittings, coupling hardware, and mounting brackets used with other LA series sensors apply directly, which simplifies specification for OEMs standardizing on the LA platform across multiple sensor sizes.

Why Winding Space Determines Sensitivity

An AC-LVDT generates its output through transformer coupling between a primary winding and two secondary windings. The more turns of wire the housing can accommodate in its secondaries, the more output voltage the sensor produces for each unit of core displacement. Housing diameter is the limiting factor: a larger bore leaves more radial space for windings. The LA-20.6's additional 1.6 mm of diameter over the 19 mm series translates directly into more winding volume and a higher sensitivity figure, expressed in mV/V/mm — millivolts of output per volt of excitation per millimeter of core travel.

Output Sensitivity and Signal Conditioner Compatibility

Higher sensitivity improves the signal-to-noise ratio at the signal conditioner input without requiring higher gain settings. This matters because amplifying a weak signal amplifies the noise along with it; starting with a stronger signal from the sensor itself is always the better path. In electrically noisy environments — motor drive cabinets, welding areas, facilities with large switching loads — the LA-20.6's sensitivity margin reduces the minimum detectable displacement, effectively improving measurement resolution with no change to the signal conditioner hardware.

As a passive AC-LVDT, the LA-20.6 requires external signal conditioning to provide excitation and convert its AC output to a usable DC signal. Both the SC-200 bench-top signal conditioner and the S2A DIN-rail module are fully compatible, and the sensor integrates into existing multichannel LVDT systems built around standard excitation frequencies.

Typical Applications

The LA-20.6 is frequently specified in precision test stands and materials testing machines where engineers want more sensitivity than the 19 mm series provides but the installation geometry cannot accommodate the LA-25's larger diameter. Load frame crosshead position feedback is a representative example: the measurement demands high resolution, the electrical environment near servo drives is noisy, and mounting space alongside the frame column is limited.

The sensor also appears in OEM positioning applications where a specific sensitivity target drives the selection and the slightly larger housing is not a constraint — precision valve position monitoring in laboratory process equipment, actuator feedback in test instrumentation, and dimensional measurement fixtures. Because an AC-LVDT's sensing element contains no electronics, the LA-20.6 also suits applications with elevated ambient temperatures that would exceed the ratings of sensors with built-in signal conditioning, with the electronics located remotely in a cooler environment.

Selecting Within the LA Series

Choose the 19 mm series when space is the overriding constraint and standard sensitivity is sufficient. Choose the LA-20.6 when the application needs additional sensitivity or noise margin and can accept the marginally larger diameter. Choose the LA-25 when maximum winding space, output level, or mechanical robustness takes priority and mounting space allows. For help matching a sensor and signal conditioner to your application, speak with an ASG application engineer at 856-727-0250.