Legrand Wattstopper DLM Explained

Wattstopper Digital Lighting Management (DLM) is Legrand's room-based lighting control platform. Legrand describes it as "an intelligent, distributed control system designed to meet Energy Codes and the control needs of commercial spaces." This guide covers how a DLM room is built, how it sets itself up, how wired and wireless DLM differ, and the model numbers you will see on a DLM submittal.

What DLM does

According to Legrand's DLM System Guide, "the DLM system integrates load control with occupancy sensors, daylight sensors, switches, dimmers, and other devices to provide simple code compliant solutions for lighting and plug load control." Each room is a self-contained DLM local network: the load controllers manage communication between the room's sensors and switches, and rooms can be networked together if desired.

How wired DLM connects

Wired DLM devices plug together with low-voltage Cat 5e cables that have standard RJ-45 connectors. Wattstopper sells these as LMRJ cables. The System Guide describes the in-room wiring as free-topology: "devices can be connected in any order (but devices should not be connected in a loop)." The same cable carries low-voltage power to the devices. Legrand allows up to 150 feet of cable per intelligent DLM device and a maximum of 1,000 feet of total cable in a room.

Room size limits, per the System Guide: a room with 110, 210 or 220 series controllers supports up to 48 DLM devices and 64 loads. A room with only 100-series controllers (or an LMPB-100 power booster) supports up to five controllers and 24 DLM devices. Total device power draw also has limits, so check the System Guide when a room is large.

Plug n' Go: how a room sets itself up

DLM devices ship pre-set for Wattstopper's Plug n' Go. Per the System Guide, "upon initial power up, the DLM system automatically identifies the devices on the Local Network, then PnG configures devices to provide the most energy efficient operation." The guide gives a wired-DLM example: in a room with two loads, a two-button switch and an occupancy sensor, load 1 turns on automatically with occupancy, load 2 must be turned on at the switch, and both turn off when the sensor's time delay expires.

Plug n' Go can be customized. Once loads are changed with Push n' Learn, the LMCT-100 configuration tool or the LMCS-100 software, Plug n' Go is locked for that room. Wireless devices are paired first, with the DLM Configuration App, LMCS-100 or button presses on the devices.

Dimming

The LMRC-21x room controllers have 0-10V dimming outputs. For loads that need forward- or reverse-phase dimming, the System Guide lists converter devices that translate the 0-10V signal, and the LMRC-22x controllers provide forward-phase dimming directly. Legrand's product guide also lists the LMAC-131-M phase-adaptive auxiliary dimming controller. Check the fixture's driver before choosing a controller.

Wired vs wireless DLM

Legrand announced the Wattstopper Wireless DLM system on May 14, 2019. According to Legrand's Wireless DLM brochure, wireless devices use a "6LoWPAN mesh, based on the IEEE 802.15.4 standard" and are paired with the DLM Configuration App over Bluetooth or by push-to-pair. The brochure says wireless DLM is "fully compatible with wired DLM room products."

There is a limit. The System Guide states that "a single room network cannot contain both wired and wireless controllers." A hybrid room is a wired load controller plus one or more wireless switches or occupancy sensors. Hybrid rooms need an LMBC-650 wireless bridge, and the wireless switches are assigned to loads with LMCS software, so a hybrid room is not plug-and-play. For a broader look at the trade-offs, see our wired vs wireless lighting controls guide.

Connecting rooms to the building

Individual rooms can be networked. The LMBC-300 wired network bridge "provides MS/TP BACnet segment wire connectivity to one DLM local network," and the System Guide explains that "wired rooms are networked together using BACnet over MS/TP running on RS-485." According to Legrand, one MS/TP segment supports up to 40 bridges or 340 devices, and Legrand recommends designing about 20% below that. For building-level control, Legrand's current DLM network controllers are the LMJA-9125-SM and LMJA-9300-SM, which Legrand's product guide lists for up to 125 and 300 rooms respectively. Older sites may have an LMSM-3E Segment Manager, which Legrand lists as discontinued.

Common DLM parts

• LMRC-211 / LMRC-212: 1- and 2-relay dimming room controllers with current monitoring.
• LMDC-100: dual-technology ceiling-mount occupancy sensor. LMPC-100: PIR ceiling-mount occupancy sensor.
• LMLS-500-L: multi-zone open-loop photosensor for daylight switching or dimming, up to three zones. This is the extended-tube version for 5/8" to 1-1/4" ceilings.
• LMPS-104: 4-button partition switch for rooms with movable walls.
• LMZC-301: zone controller that supplies network power and scheduling. It has no relays, so it does not switch loads itself.
• LMBC-300: wired network bridge to BACnet MS/TP.
• LMCT-100-2: handheld infrared configuration tool for wired DLM devices.

Discontinued: the System Guide lists the LMSW-10x switches, LMDM-101, LMSW-605 and LMDM-601 as discontinued. For the LMDM-101 dimmer, technical support on Legrand's LMDM-101 product page names the LMSW-211 or LMSW-222 as replacements.

Energy savings and codes

Legrand says DLM is "designed by default to provide maximum energy savings" and that "optimizing energy performance with DLM makes it easy to meet the latest code requirements." Which controls a project needs depends on the energy code your jurisdiction has adopted, so confirm the sequence of operations with your design team.

Get DLM from Rock

Rock Lighting & Electric stocks Wattstopper DLM room controllers, sensors, switches and bridges. Comparing platforms? See DLM vs nLight and DLM vs Lutron Vive. Create a contractor account for project pricing, request a quote, or contact us with your room list and we will match parts to it.

Related guides

• Wattstopper DLM vs nLight compared
• Wattstopper LMRC-211 room controller
• Wattstopper LMDC-100 dual-tech sensor
• Wattstopper LMSW-105 Scene Switch: Specs, and What Replaced It

Frequently asked questions

What does DLM stand for in Wattstopper DLM? Digital Lighting Management. Legrand describes Wattstopper DLM as an intelligent, distributed control system that combines load control with occupancy sensors, daylight sensors, switches and dimmers for commercial spaces.

How are wired DLM devices connected? With low-voltage Cat 5e cables with RJ-45 connectors, sold as LMRJ cables. Legrand's DLM System Guide says devices can be connected in any order but should not be connected in a loop. The cable also carries low-voltage power, and Legrand allows up to 150 feet of cable per intelligent DLM device and 1,000 feet of total cable in a room.

What is Plug n' Go? Wattstopper's automatic setup for DLM. In a wired room, on first power-up the system identifies the devices on the room network and Plug n' Go configures them for the most energy-efficient operation. Wireless devices must be paired first, with the DLM Configuration App, LMCS-100 software or button presses. Customizing loads with Push n' Learn, the LMCT-100 tool or LMCS-100 software locks Plug n' Go.

Is there a wireless version of Wattstopper DLM? Yes. Legrand announced Wireless DLM in 2019. It uses a 6LoWPAN mesh based on IEEE 802.15.4, and devices are paired with the DLM Configuration App over Bluetooth or by push-to-pair. Per Legrand's DLM System Guide, one room cannot contain both wired and wireless controllers. A hybrid room pairs a wired load controller with wireless switches or occupancy sensors through an LMBC-650 bridge, and the wireless switches are assigned to loads with LMCS software.

Is the Wattstopper LMDM-101 dimmer discontinued? Yes. Legrand's DLM System Guide lists the LMDM-101 as discontinued. Technical support on Legrand's LMDM-101 product page names the LMSW-211 or LMSW-222 as replacements. Confirm the replacement against your room's controllers before ordering.

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