Casambi PWM lighting control uses a Casambi-enabled PWM dimmer, such as the CBU-PWM4-LR family, to control 12–24 VDC constant-voltage LED strips and modules. Up to four common-positive output channels can be configured for independent dimming, tunable white, RGB, RGBW or two tunable-white loads, subject to the selected fixture profile and combined current limit. The numerical specifications in this article apply specifically to the CBU-PWM4-LR and CBU-PWM4-4-LR. Other Casambi Ready PWM controllers may use different input voltages, channel counts, PWM frequencies and current limits.

Quick Facts

• Covered hardware: CBU-PWM4-LR and CBU-PWM4-4-LR
• Load type: 12–24 VDC constant-voltage LED loads
• Output style: four common-positive PWM channels
• Typical modes: independent dimming, tunable white, RGB, RGBW, 2×TW
• Combined current: 6 A for CBU-PWM4-LR; 4 A for CBU-PWM4-4-LR
• PWM frequency: 400 Hz for the CBU-PWM4-LR family
• Enclosure rating: IP20 indoor device
• Profile note: the device uses one selected fixture profile at a time

What Is Casambi PWM Lighting Control?

Casambi PWM lighting control is a wireless control method for constant-voltage LED loads. In this article it is explained through the CBU-PWM4-LR family, a four-channel PWM dimmer used for 12–24 VDC LED strips and modules. A Casambi PWM controller receives commands from the Casambi network and modulates DC output channels for dimming or color mixing.

For clarity, this page does not claim that every Casambi Ready PWM product shares the same current limit, wiring arrangement or installation class. In specification work, a Casambi PWM controller should always be identified by exact model rather than by brand name alone. The discussion is intentionally centered on the CBU-PWM4-LR family.

Which Casambi PWM Controllers Are Covered?

This page focuses on the CBU-PWM4-LR family rather than the entire Casambi ecosystem. That distinction matters because Casambi Ready products also include third-party PWM controllers and other control formats.

The original Casambi CBU PWM4 has been discontinued. Its current long-range successors include the 6 A CBU-PWM4-LR for the EU and related markets and the 4 A CBU-PWM4-4-LR for the United States and Canada. When 12–24 VDC input, 400 Hz PWM, common-positive behavior, 4 A or 6 A combined current or North American Class 2 constraints are discussed below, those points refer to the CBU-PWM4-LR family rather than to all Casambi Ready PWM devices.

CBU-PWM4-LR vs CBU-PWM4-4-LR

The two current LR models serve similar applications but are not identical.

• CBU-PWM4-LR: current long-range 6 A model for the EU and related markets
• CBU-PWM4-4-LR: current long-range 4 A model for the United States and Canada
• Original Casambi CBU PWM4 4 naming may still appear in older documents, but the active North American model is CBU-PWM4-4-LR. In older search language, buyers may still look for a Casambi 4 channel controller even when they specifically need the LR family.

A practical comparison is:

• Input voltage: 12–24 VDC constant-voltage supply on both LR models
• Output channels: four PWM channels on both LR models
• Combined output current: 6 A on CBU-PWM4-LR, 4 A on CBU-PWM4-4-LR
• PWM frequency: 400 Hz for the CBU-PWM4-LR family
• Load style: common-positive constant-voltage LED loads
• North American note: the CBU-PWM4-4-LR is described as a UL Listed Open-Type device and is intended for use with a Class 2 power supply with maximum output power of 100 VA

How Does the Power and Control Architecture Work?

The control path and power path should be understood separately.

Control Path

Casambi-enabled apps, switches, sensors, timers and automations operate as network nodes inside the Casambi system. They do not connect to a dedicated sensor terminal on the CBU-PWM4-LR. Instead, they trigger control actions over the shared Casambi network, and the controller responds as one device on that network.

The CBU-PWM4-LR has no dedicated switch or sensor input. Dimming, scenes, color control and automation can be triggered by separate Casambi-enabled switches and sensors on the same network. Because the controller is powered through an external DC power supply, Casambi’s Smart Switching feature for direct-mains devices does not apply.

Power Path

The electrical path is separate: AC mains feeds a constant-voltage power supply; the power supply feeds the CBU-PWM4-LR family controller; and the controller modulates the LED load. The controller does not replace the power supply, and it does not convert one DC voltage into another.

How Does 400 Hz PWM Dimming Work?

The CBU-PWM4-LR family modulates output at 400 Hz. PWM dimming works by switching each output channel on and off rapidly within each PWM period while maintaining the nominal DC supply for the LED load.

A 50% PWM duty cycle means that the output is electrically switched on for approximately half of each PWM period. It should not automatically be interpreted as 50% perceived brightness or exactly 50% measured lumens, because the fixture profile, dimming curve, LED characteristics, optics and human visual response also affect the result.

For photography, broadcasting, high-speed video or machine-vision environments, actual flicker testing should be performed instead of assuming that 400 Hz guarantees suitability in every case.

CBU-PWM4 Fixture Profiles and Channel Mapping

Fixture profile selection is one of the most important parts of Casambi PWM lighting control because it defines how the four physical outputs are interpreted by the app and by the luminaire.

Typical examples include:

• one-channel dimming profile for a single constant-voltage load
• multi-channel profile for two, three or four independent outputs
• tunable-white profile for one warm-plus-cool luminaire
• RGB profile for red, green and blue channels
• RGBW profile for red, green, blue and white channels
• 2×TW profile for two separate tunable-white loads using four outputs

Current documentation indicates that RGBW Profile 4027 is the default factory profile for current products. A Casambi 4 channel controller can therefore look like one RGBW luminaire, one tunable-white luminaire or several independent channels depending on the selected profile.

A CBU-PWM4-LR fixture profile is changed while the device is unpaired. After changing the profile, verify the physical channel wiring before adding the controller back to the network and recommissioning its scenes and controls.

Tunable White vs RGB vs RGBW Control

The same hardware platform can be configured for different output behaviors, but only one selected fixture profile is active at a time.

Tunable White

Tunable-white control uses two channels, normally mapped to warm white and cool white. The Casambi profile coordinates those channels in the user interface, but the actual minimum and maximum CCT depend on the LED source, drive ratios, LED binning, optics, mixing behavior and thermal state. In project language this is the operating basis of Casambi tunable white control. Good Casambi tunable white control also depends on correct warm/cool channel mapping and luminaire-level photometric validation.

RGB

RGB control uses three channels for red, green and blue mixing. The selected profile maps those outputs to app controls and scenes. For decorative applications, Casambi RGB control depends on correct channel order and combined load calculations. Reliable Casambi RGB control also requires the selected profile to match the actual red, green and blue wiring order.

RGBW

RGBW adds a fourth white channel to the RGB set. This can improve scene flexibility and separate white illumination from colored mixing. In practice, Casambi RGBW control still depends on the actual LED load, not on the controller alone. Stable Casambi RGBW control therefore requires both correct profile assignment and correct total-load sizing.

The same CBU-PWM4-LR hardware can be configured for tunable white, RGB or RGBW, but it uses one selected fixture profile at a time. Four physical outputs cannot simultaneously provide a two-channel tunable-white output and a full four-channel RGBW output.

Common-Positive Wiring

The CBU-PWM4-LR family is intended for common-positive constant-voltage LED loads. In this arrangement, the positive supply is shared, while the controller modulates the individual channel outputs.

This makes correct channel order essential. The physical wiring sequence must match the selected fixture profile and the official wiring diagram. If warm and cool channels are reversed, or if RGBW outputs are connected in the wrong order, control behavior will not match the intended result. This is also why a Casambi LED strip controller must be matched carefully with the strip’s wiring format. A Casambi LED strip controller should never be selected by voltage alone without checking channel arrangement and total current.

How to Calculate Voltage, Current and Total Load

The core electrical checks are straightforward.

First, match voltage across the LED load, the power supply and the controller input. The CBU-PWM4-LR family is designed for 12–24 VDC constant-voltage systems. It does not convert 24 V to 12 V, and it must not be connected directly to mains.

Second, calculate each channel load from the maximum connected wattage. Third, add the maximum simultaneous channel loads to determine combined current demand. For the CBU-PWM4-LR family, the published 6 A or 4 A value is a combined controller limit, not a per-channel entitlement. In other words, Casambi multi channel lighting control must always be checked against the worst-case simultaneous load. Safe Casambi multi channel lighting control is based on maximum simultaneous demand, not on a favorite scene preset.

Fourth, check the selected power supply, wire size, cable length, enclosure temperature and any regional supply-class rules.

Worked 24 V Load-Sizing Example

Example: A 24 V RGBW load has maximum channel loads of 18 W red, 18 W green, 18 W blue and 24 W white. Maximum simultaneous load = 78 W. Total current = 78 W ÷ 24 V = 3.25 A.

That 3.25 A total is below the 6 A combined limit of the CBU-PWM4-LR and also below the 4 A combined limit of the CBU-PWM4-4-LR. However, the installer still needs to confirm conductor size, LED strip ratings, power-supply capacity, thermal conditions and, in North America, the Class 2 power-supply limit of 100 VA where applicable.

The calculation should always use maximum possible simultaneous output, not just a typical everyday scene. If a strip is rated in watts per meter per channel, all channels that may operate together must be included in the total.

Installation, Thermal and Radio Requirements

The CBU-PWM4-LR family is an IP20 indoor device. It is specified for an ambient temperature range of -20 to +45°C and relative humidity of 0–80% non-condensing. Input and output lead lengths should be kept within the stated product limits, commonly up to 3 m, and suitable conductor sizes should match the relevant specification, such as 0.75–1.5 mm² or 14–22 AWG depending on the documentation version and market context.

These controllers should not be installed inside a metal enclosure or immediately next to large metal structures if wireless range is important. Antenna location, luminaire housing, walls and building materials all influence radio performance.

Published reference figures for Long Range are ideal values of up to about 50 m indoors and up to about 200 m in open line-of-sight conditions, and the network mode and other participating nodes must also support Long Range.

Profile Selection and Commissioning

During commissioning, confirm the voltage class, the constant-voltage power-supply type, the selected fixture profile, the physical channel mapping and the combined current calculation.

If a profile change is needed, unpair the device first, change the profile, verify wiring against the chosen profile and then add the unit back to the network. Common commissioning problems can originate from voltage mismatch, incorrect profile selection, channel mapping, polarity, excessive load or wireless installation conditions.

Troubleshooting Table

• No output: check DC supply voltage, polarity, upstream power supply and network pairing status
• Wrong colors or wrong CCT direction: check fixture profile and channel order
• Unstable behavior at high load: check combined current, wiring length and thermal conditions
• Poor wireless range: check metal enclosure conditions, antenna location and LR compatibility in the network
• Scene works incorrectly after reconfiguration: confirm that the device was unpaired before profile change and recommission scenes afterward

What Can the CBU-PWM4-LR Not Control Directly?

The CBU-PWM4-LR family has clear boundaries. It cannot convert 24 V into 12 V. It cannot connect directly to mains. It cannot directly drive constant-current LED modules. It is not a 0–10 V controller and not a DALI controller. It cannot control addressable or SPI pixel LED strips. With only four outputs, it cannot directly control a full five-channel RGB+CCT or RGBCCT load. Because it is an IP20 device, it is not an outdoor waterproof controller by itself.

Applications

The CBU-PWM4-LR family is commonly suited to architectural LED strips, cove lighting, joinery lighting, hospitality accents, retail displays, tunable-white linear fixtures, RGB decorative luminaires and RGBW constant-voltage lighting systems.

FAQ

What is Casambi PWM lighting control?

Casambi PWM lighting control uses a Casambi-enabled PWM dimmer, such as the CBU-PWM4-LR family, to control 12–24 VDC constant-voltage LED strips and modules through one selected fixture profile and up to four common-positive output channels.

Can the CBU-PWM4-LR drive constant-current LED modules?

No. The CBU-PWM4-LR and CBU-PWM4-4-LR are designed for 12–24 VDC constant-voltage LED loads. They must not be connected directly to a constant-current LED load. Other Casambi Ready controllers and drivers may support different load types.

What is the PWM frequency of the CBU-PWM4-LR?

The CBU-PWM4-LR family uses 400 Hz PWM output according to current product documentation.

Does 50% PWM mean 50% perceived brightness?

No. A 50% duty cycle means the output is electrically on for about half of each PWM period. Perceived brightness and measured lumens also depend on the fixture profile, dimming curve, LED characteristics, optics and human visual response.

Does the CBU-PWM4-LR have a sensor or push-button input?

No. The CBU-PWM4-LR has no dedicated switch or sensor input. Separate Casambi-enabled switches and sensors can trigger actions over the network.

Must the controller be unpaired before changing its profile?

Yes. A CBU-PWM4-LR fixture profile is changed while the device is unpaired. After changing the profile, verify wiring and recommission the device when it is added back to the network.

Can one CBU-PWM4-LR control two tunable-white LED loads?

Yes, if the selected fixture profile supports a 2×TW arrangement and the total electrical load remains within the controller’s limits.

Can the CBU-PWM4-LR control addressable or SPI LED strips?

No. It is a four-channel PWM controller for constant-voltage LED loads, not an SPI or pixel-addressable controller. The CBU-PWM4-LR family is not a universal Casambi PWM controller for every LED protocol.

Can it control five-channel RGB+CCT lighting?

Not directly as a full five-channel load, because the controller has four outputs.

Can the CBU-PWM4-LR be installed outdoors?

Not as an exposed controller. The device is rated IP20 and is intended for indoor use within the specified environmental limits.

Official Technical Sources

This article is based on the CBU-PWM4-LR and CBU-PWM4-4-LR product pages and related technical specifications. Because profile lists, regional approvals and detailed limits can change, final project decisions should always be checked against the latest Casambi documentation for the exact market and model.