A 38 mm roller tube narrows the motor list fast. The Somfy Sonesse 40 RS485 404S2 fits that tube and turns it at 36 rpm with 4 Nm of torque, which suits small interior shades in offices, clinics and classrooms. Specifiers reach for this motor when a job wants addressable wired control in place of radio.
Tube diameter decides this motor
Somfy publishes a minimum internal tube diameter of 1.46 in for the 404S2. The motor body measures 1.39 in across, which leaves clearance for the crown and the drive inside a 38 mm tube. Measure the inside of the tube before you order. A 40 mm octagonal tube with a 0.8 mm wall gives you the inside diameter this motor wants, and a 40 mm round tube with a 1.5 mm wall does the same.
The motor runs 20.24 in long and carries a round head. Somfy sets the riveting position at 19.02 in from the drive end, so plan tube length around that figure. Unwrapped weight comes in at 2.76 lb. A narrow shade on a single motor plate holds it without extra support.
Shade types the 404S2 drives
Four newton meters moves a useful amount of interior fabric on a 40 mm tube. Somfy rates traction force at 15.44 lb. Shade width, fabric weight and roll diameter set the real ceiling, and the 400 Series databook carries the sizing tables for each torque step in the family.
At 36 rpm the shade travels quick, which keeps a bank of narrow windows looking even when they run as a group. The electronic limit switch stores 250 turns of travel, enough for a tall opening on a small tube. Offices, patient rooms, hotel corridors and lecture halls all run this motor, since each one wants a shade that answers a building command instead of a handheld remote.
Verified specs for the 404S2
| Reference | 1240562 |
| Somfy code | 404S2 Sonesse 40 RS485 4/36 FC |
| Torque | 4 Nm |
| Speed | 36 rpm |
| Traction force | 15.44 lb |
| Control | RS485 bus, Somfy Digital Network |
| Power supply | 120V / 60Hz, range 108V to 132V |
| Current | 0.95 A |
| Power consumption | 114 W running, 0.5 W standby |
| Limit switch | Electronic, 250 turns |
| Repeatability | Plus or minus 4 |
| Head type | Round |
| Cable | SVT, 2 wires, 1.64 ft, white, Fast Connector |
| Motor external diameter | 1.39 in |
| Minimum tube inside diameter | 1.46 in |
| Overall length | 20.24 in |
| Riveting position | 19.02 in |
| Weight | 2.76 lb |
| Noise level | 42 dB |
| Protection index | IP 31 |
| Insulation class | Class II |
| Thermal time | 4 min |
| Operating temperature | 32 F to 140 F |
| Storage temperature | -4 F to 167 F |
| Warranty | 5 years |
Figures above come from Somfy's own published data for reference 1240562.
Crowns, drives and brackets for a 40 mm tube
Somfy builds the 400 Series crown and drive sets around this motor family. The Somfy LS40 Crown and Drive Set (9012224) seats the 404S2 in a 40 mm round tube with a 1.5 mm wall. Cutting new tube for the job calls for Somfy 40mm Octagonal Tube (1781154), which ships by the foot in 20 ft increments and pairs with the octagonal rubberized crown set.
On the bracket side, the Somfy RollEase 1.5 inch Bracket Kit R8 Series (9012311) carries the round head on a 40 mm round tube. The head needs a motor plate that matches its pin pattern, so confirm the plate before you fix bracket spacing in the pocket. Use 40 mm parts throughout. Crowns and drives built for 28 mm or 50 mm tubes will not seat on this motor.
SDN wiring, control and commissioning
RS485 gives the 404S2 a two-way link. The motor reports its position and status back up the bus, and a controller addresses it alone or inside a group. Somfy fits a 1.64 ft white SVT cable with two wires, terminated in a Fast Connector. That short tail keeps the headbox tidy and lets an installer plug a prewired harness into the motor without stripping conductors inside the pocket.
Power comes from 120V at 60Hz, with an accepted range of 108V to 132V. The motor draws 0.95 A and 114 W while it drives the shade, then settles to 0.5 W at rest. Somfy rates it Class II with IP 31 protection, which places it inside the building envelope. Noise sits at 42 dB, low enough for a conference room wall or a patient room.
Somfy's animeo IP platform picks the motor up as an addressable device on the same bus, so a building management system can drive a whole facade from one schedule. Larger SDN jobs feed the bus through Somfy power distribution gear rated for the motor count on the run.
Limits on this motor are electronic. An installer sets them with a bus tool, not with screws on the head. The Somfy RS485 Setting Tool (9017142) handles limit setting and addressing at the shade, which earns its place on a lift where a laptop gets awkward. For bench work and floor-wide commissioning, the Somfy USB to RS485 Adaptor for SDN (9015260) links the bus to a PC running Somfy's SDN software.
Somfy publishes repeatability at plus or minus 4, so a row of shades lands even across a run of windows. Thermal time runs 4 minutes of continuous travel before the motor pauses to cool. Operating range covers 32 F to 140 F, and storage holds from -4 F to 167 F.
Order the 404S2 with the parts it needs
The Somfy Sonesse 40 404S2 RS485 SDN Motor (1240562) carries a UL listing and a 5 year Somfy warranty. Order the crown and drive set alongside the motor, since the two ship as separate items and a missing drive stops an install cold. On a job running more than a handful of shades, buy the USB adaptor once and carry it from floor to floor.
Two siblings share this platform at higher torque, the 406A2 at 6 Nm and the 409R2 at 9 Nm. Tube size stays the same across all three, so the choice comes down to fabric weight and roll diameter.
Frequently asked questions
What tube does the Sonesse 40 404S2 fit?
Somfy publishes a minimum internal tube diameter of 1.46 in, which matches a 40 mm tube. A 40 mm octagonal tube with a 0.8 mm wall and a 40 mm round tube with a 1.5 mm wall both clear the 1.39 in motor body. Pair the tube with a 400 Series crown and drive set.
How do you set limits on an RS485 Sonesse 40?
Limits are electronic on this motor. Set them over the bus with the Somfy RS485 Setting Tool at the shade, or with a PC and the USB to RS485 adaptor running Somfy SDN software. The limit switch stores up to 250 turns of travel, and repeatability holds at plus or minus 4.
Does the 404S2 work with an RTS remote?
The 404S2 takes every command over its RS485 bus connection, which is what makes two-way feedback and addressing possible. Somfy builds separate RTS and Zigbee versions of the Sonesse 40 for radio control, so pick the version that matches the control layer the project specifies.
What power does the 404S2 need?
The motor runs on 120V at 60Hz and accepts 108V to 132V. It draws 0.95 A and 114 W while driving a shade, then drops to 0.5 W standby. Somfy rates the motor Class II with an IP 31 protection index, so keep the install inside the building envelope.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
