The Wattstopper LMDC-100 is a Digital Lighting Management (DLM) ceiling-mount occupancy sensor that combines two detection technologies, passive infrared (PIR) and ultrasonic, in one low-profile housing. Rock Lighting stocks the LMDC-100 as part of the Wattstopper DLM line. Here is what the part number covers and where it fits against single-technology sensors.
What "dual technology" means on the LMDC-100
PIR sensors detect the heat signature of motion in a direct line of sight; they can miss small or slow motion, and they lose coverage around obstructions like cubicle partitions. Ultrasonic sensors detect motion by sound-wave reflection and cover around obstructions, but can be more prone to false triggers from HVAC airflow or vibration in isolation.
The LMDC-100 requires both technologies to agree before it commits to an occupied or vacant state, per Wattstopper's own detection signature processing. That combination is why Wattstopper positions the LMDC-100 for spaces like conference rooms, private offices, open offices, and classrooms, where a single-technology sensor is more likely to produce false triggers or gaps in coverage.
Specs (per manufacturer datasheet)
- Sensor type: digital dual technology, passive infrared + ultrasonic
- Coverage: 1,000 sq ft at a standard ceiling mount
- Viewing angle: 360°
- Sensitivity: 90% PIR, 70% ultrasonic
- Ultrasonic response frequency: 40 kHz
- Voltage: 24 VDC
- Amperage: 20 mA
- Time delay: 1 to 30 minutes (field adjustable)
- Connection: RJ45, on a free-topology Category 5e DLM local network
- Control output: automatic ON/OFF
- Dimensions: 4-1/4" diameter x 2" deep
- Operating temperature: 32°F to 104°F
- Listings: UL 244A, cUL Listed, FCC Part 15 compliant, RoHS compliant
How it wires into a DLM system
The LMDC-100 is not a standalone line-voltage sensor. It is a DLM component, meaning it plugs into a free-topology Category 5e local network alongside other DLM devices (room controllers, switches, photosensors), daisy-chained rather than home-run wired. Configuration happens either through the pushbuttons and LCD display behind the sensor's snap-off front cover, or wirelessly using Wattstopper's IR configuration tool, with Plug n' Go automatic configuration available for a fast initial setup.
For the room controller that a DLM sensor like the LMDC-100 typically pairs with, see our explainer on the Wattstopper LMRC-211 single-relay room controller.
Where the LMDC-100 fits versus a single-technology sensor
If a space has a simple, unobstructed layout with clear sightlines (a small private office, a storage room), a single-technology PIR sensor is often sufficient and lower cost. Reach for a dual-technology sensor like the LMDC-100 when the room has partitions, irregular seating, or occupants who sit relatively still for long stretches (conference rooms, classrooms with desk work), where PIR alone risks a false "vacant" reading and turning the lights off on someone still in the room.
Rock Lighting stocks the Wattstopper DLM line, including the LMDC-100 and its companion room controllers and switches. See also our Commercial Occupancy Sensor Buying Guide and Legrand Wattstopper DLM Explained.
Frequently asked questions
What does "dual technology" mean on the Wattstopper LMDC-100?
It combines passive infrared (PIR) and ultrasonic detection in one sensor. Wattstopper's detection signature processing requires signals consistent with both technologies before changing occupancy state, which reduces false triggers compared to a single-technology sensor.
What area does one LMDC-100 cover?
1,000 sq ft at a standard ceiling mount, with a 360° viewing angle, per the manufacturer datasheet.
Does the LMDC-100 run on standard line voltage?
No. It operates at 24 VDC as part of a Wattstopper DLM (Digital Lighting Management) system, connected via RJ45 on a free-topology Category 5e local network alongside other DLM devices.
How is the LMDC-100 configured?
Through pushbuttons and an LCD display behind the sensor's snap-off front cover, or wirelessly with an IR configuration tool. It also supports Plug n' Go automatic configuration for initial setup.
What spaces is the LMDC-100 recommended for?
Wattstopper recommends it for conference rooms, private offices, open offices, and classrooms, where relying on a single detection technology raises the risk of false triggers or missed occupancy.
Does Rock Lighting stock the Wattstopper LMDC-100?
Yes. Rock Lighting carries the LMDC-100 and the broader Wattstopper DLM line. Browse the Wattstopper collection or contact us for current stock.
Building out a DLM zone and need help pairing sensors to controllers? Request a quote, contact us, or register for a contractor account.
This guide is general information. Specifications are sourced from the Wattstopper/Legrand LMDC-100 manufacturer datasheet and may change without notice; confirm current figures against the manufacturer spec sheet or your quote before final purchase.