USB to 4 Relays and DMX–RGB: Automation and Color Without the Mystery
In day 13 , relays lived in the DMX universe: the lighting console fired fog, curtains, and loads through D21R / D28R. Day 11 was the Ethernet web panel; day 12was Modbus TCP. Today we add two complementary local tools — not the same bus —: the U24R (USB to 4 relays from a PC) and the DMX-RGB-AIO (DMX to common-anode RGB, 4 modes). Dry contacts for the bench or home automation, and LED color from the console, without mixing contracts.
The practical rule is simple: who owns timing. If PC software is master, use USB. If the show lives in DMX cues, use DMX-driven RGB. Shop categories: USB – Relay and DMX – RGB.
Two paths, two owners of time
This is not “USB versus DMX” as a contest. They are different layers that often sit in the same workshop or venue:
- U24R (USB → 4 relays): the PC opens and closes dry contacts. Ideal for bench robotics, home automation, light industrial control, and tests without a lighting console.
- DMX-RGB-AIO (DMX → RGB): the lighting universe paints common-anode RGB strips or fixtures. The lighting director moves color like any other DMX fixture.
- Day 13 (DMX → relay): if you need contacts from the console (fog, curtain), stay with D21R / D28R — not U24R.
Choose USB when a script, a .NET panel, or a lab owns timing. Choose DMX–RGB when color must live next to the wash and the mover in the patch. If the plant already lives in SCADA, go back to day 12; if the electrician operates from a browser, day 11.
- PC / USB side
- Notebook or PC with a USB port
- Included software plus open-source .NET and VB6 examples
- U24R: four relays at 220 V / 7 A
- Use: automation, home automation, industrial control
- Show / DMX side
- Console or DMX interface / Art-Net node into DMX512
- DMX-RGB-AIO: common-anode RGB output
- 4 DMX modes (3 / 4 / 7 channels) via a 2-way DIP
- Automatic or DMX mode; Power + DMX signal LEDs
- What not to mix
- U24R does not speak DMX, Ethernet, or lighting-console language
- DMX-RGB-AIO does not speak USB, relays, or web panel
U24R: four contacts from the USB port
The U24R is ElectroTAS’s USB-to-4-relay converter: you drive four relay states from a computer USB port. Think bench robotics, automation, home automation, and light industrial control where the “master” is PC software — not a console fader.
| Feature | Confirmed value |
|---|---|
| Model | U24R — USB to 4-Relay Converter |
| Control | 4 relays via USB |
| Typical use | Automation / home automation / industrial control |
| Software | Included; open-source .NET and VB6 examples |
| Contact rating | 220 V, 7 A |
| Cable | USB Type-B included |
| Temperature | −20 °C to 50 °C |
| Weight / size | 72 g · 87×60×25 mm |
| Package | Board + USB Type-B cable |
Shop EN: U24R. Shop ES: U24R (ES). Category: USB – Relay.
What we do not claim: DMX, Art-Net, Ethernet, PoE, Modbus, a web panel, lighting-console control, invented API maps, or undocumented pinouts. This is USB → 4 relays. Command details, drivers, and examples live in the included software and the open-source .NET / VB6 material — we do not invent an API in this article.
- Control origin
- PC or notebook with an app / .NET or VB6 examples
- Local software owns timing (script, UI, bench logic)
- USB link
- PC USB port
- USB Type-B cable (included in the package)
- U24R board
- Four relays rated 220 V / 7 A
- Compact format 87×60×25 mm · 72 g
- Thermal range −20 °C to 50 °C
- Loads
- Contacts toward loads within rating, or a contactor coil when power is higher
- Bench tests, home automation, signals to other racks
DMX-RGB-AIO: LED color from the DMX universe
The DMX-RGB-AIO is a compact board for driving RGB LED devices with a DMX signal. Common-anode output, up to 4 A per channel (Imax = 12 A), 12 V DC supply, Automatic or DMX modes, plus Power and DMX signal LEDs for a quick visual check.
It offers 4 DMX modes with 3 / 4 / 7 channels, selected via a 2-way DIP. Here we only state that those modes exist and how the datasheet frames selection: concrete DIP tables, per-mode channel maps, and addressing live in the official manual in the box — we do not invent truth tables or channel maps in the blog.
| Feature | Confirmed value |
|---|---|
| Model | DMX-RGB-AIO — DMX to RGB Controller (4 modes) |
| Function | Control RGB LED devices via DMX |
| Current | 4 A max per channel (Imax = 12 A) |
| DMX modes | 4 modes · 3 / 4 / 7 channels (2-way DIP) |
| Supply | 12 V DC |
| Operating modes | Automatic or DMX |
| Indicators | Power LED + DMX signal LED |
| RGB output | Common-anode |
| Temperature | −20 °C to 50 °C |
| Weight / size | 50 g · 130×35×25 mm |
| Package | Board + manual |
Shop EN: DMX-RGB-AIO. Shop ES: DMX-RGB-AIO (ES). Category: DMX – RGB.
What we do not claim: USB, Ethernet, PoE, onboard Art-Net, Modbus, relays, a web panel, or an app. This is DMX → common-anode RGB. If your console speaks Art-Net, use a node into DMX512 and then hang this board on the bus — context in what Art-Net is and USB–DMX vs Art-Net.
- Control origin
- Physical console or PC with a DMX interface / Art-Net node
- Patch: lighting fixtures plus an RGB receiver in the same universe
- DMX512 link
- Universe DMX bus
- The board appears as a field RGB device
- DMX-RGB-AIO board
- 12 V DC supply
- 2-way DIP: pick one of 4 modes (3 / 4 / 7 channels) per the manual
- Automatic or DMX mode; Power + DMX signal LEDs
- Common-anode RGB output · up to 4 A/channel (Imax 12 A)
- Optical load
- Common-anode RGB strips or fixtures within current rating
Quick comparison: U24R vs DMX-RGB-AIO
| Aspect | U24R | DMX-RGB-AIO |
|---|---|---|
| Control bus | USB from a PC | DMX512 from console / universe |
| What it drives | 4 relays (contacts) | Common-anode RGB output |
| Key rating | 220 V / 7 A per contact | 4 A/channel (Imax 12 A) |
| Software / modes | Included software; .NET / VB6 examples | 4 DMX modes (3/4/7 ch) via DIP; Auto or DMX |
| Indicators | (datasheet: USB control + relays) | Power LED + DMX signal LED |
| Logic supply | Via USB / board design | 12 V DC |
| Weight / size | 72 g · 87×60×25 mm | 50 g · 130×35×25 mm |
| Package | Board + USB Type-B cable | Board + manual |
| When to pick it | PC software owns contact timing | Console owns show color |
Golden rule: if you need contacts from the console, do not force the U24R — use the day 13 path (D21R / D28R). If you need color from a PC over USB, this post does not invent a USB RGB driver: the DMX-RGB-AIO is DMX.
Use cases: bench, home, and show
- Robotics bench / lab: U24R fires small motors (via contactor if needed), solenoids, or test signals from a .NET script without standing up a DMX universe.
- Home automation: four contacts for service lights, pumps, or zones — always within 220 V / 7 A or through a contactor.
- Light industrial control: a line-side PC opens/closes process contacts; included software and open-source examples speed the prototype.
- Small-stage RGB wash: DMX-RGB-AIO paints common-anode strips from the same patch as the rest of the show.
- Fixed install with a resident console: architectural or room color lives in DMX; effect relays stay on D21R/D28R when the trigger is console-side.
- Hybrid show: USB backstage for load tests; DMX on stage for color — two buses, no mystery.
If relay triggers must come from a PLC or SCADA tag, day 12. If the operator is the electrician with a laptop on the LAN, day 11. If the fog machine must live in the lighting cue, day 13.
- Install the included software and review the open-source .NET / VB6 examples before wiring real loads.
- Connect the USB Type-B cable (included) between the PC and the board.
- Confirm the OS sees the device per the package instructivo — we do not invent driver steps here.
- Bench-test each relay with a safe load (lamp or test contactor coil) before installation mains.
- Document which software output moves which physical contact. Label terminals.
- Respect 220 V / 7 A; if the load is heavier, pilot a contactor.
- Only then integrate the real automation (home, bench, or line).
- Power with 12 V DC sized for strip / fixture current (respect 4 A/channel and Imax 12 A).
- Confirm your LED is common-anode — this board’s datasheet requires it.
- Connect the DMX bus; confirm Power and DMX signal LEDs.
- Select the mode (3 / 4 / 7 channels) with the 2-way DIP per the official manual — no invented tables in this post.
- Choose Automatic or DMX mode per the instructivo.
- Patch the base address on the console following the manual; test color on the bench at limited current.
- Document DIP mode + address + physical fixture. Only then take it into the show.
Safety: 220 V on relays and amperage on RGB
Two different risks, two disciplines:
- U24R — 220 V power: contacts handle up to 7 A. If the load exceeds rating, use a contactor. If you are not qualified for mains wiring, hire someone who is.
- DMX-RGB-AIO — LED current: 4 A per channel and Imax 12 A are not “a panel LED.” Size the 12 V supply, cabling, and dissipation; do not overload the strip or the board.
- Separate the buses: keep PC USB away from 220 V terminals; keep the DMX bus away from undersized strip power.
- Temperature: both products: −20 °C to 50 °C; reasonable airflow in rack or enclosure.
- Common-anode: wrong RGB polarity can damage the load or the output — check LED and receiver datasheets.
How this fits Art-Net, USB–DMX, and the rest of the roadmap
The U24R does not replace a USB–DMX interface: it does not create a lighting universe. To take a PC into the DMX world, follow USB–DMX vs Art-Net and Art-Net basics. The DMX-RGB-AIO hangs on the DMX512 leg like any color fixture — if you arrive over Art-Net, the node converts and then RGB joins the bus.
“Who is master” summary:
- Day 11: Ethernet web panel (LAN operator).
- Day 12: Modbus TCP (SCADA / PLC).
- Day 13: DMX → relay (console fires contacts).
- Today: USB → 4 relays (PC fires contacts) + DMX → RGB (console paints color).
FAQ
1. Can the U24R be driven from a lighting console?
No. It is USB from a PC. For relays from DMX, use D21R / D28R (day 13).
2. Does the DMX-RGB-AIO connect over USB?
No. It is a DMX-to-RGB receiver. USB is not on this model’s datasheet.
3. Where is the DIP table / 3-4-7 channel map?
We do not invent it in the blog. Use the official manual included with the board and ElectroTAS support.
4. What software ships with the U24R?
Included software plus open-source .NET and VB6 examples. We do not publish an invented API or undocumented pinouts here.
5. Common-anode or common-cathode?
The datasheet confirms common-anode output. Verify your strip / fixture is compatible.
6. Can I power the RGB over PoE or onboard Art-Net?
We do not claim PoE or onboard Art-Net on this board. Supply is 12 V DC; Art-Net arrives via a node to DMX512.
7. What if my relay load exceeds 7 A?
Pilot a contactor with the U24R relay. Do not push the contact past 220 V / 7 A.
8. When do I choose U24R vs DMX-RGB-AIO?
Contacts from PC software: U24R. LED color from the lighting universe: DMX-RGB-AIO. They are not interchangeable.
Wrap-up and next step
Two tools, two clear contracts: the U24R puts four 220 V / 7 A contacts under your PC software; the DMX-RGB-AIO puts common-anode color under the DMX patch with four modes (3 / 4 / 7 channels) documented in the manual. Shop: U24R · DMX-RGB-AIO · USB – Relay · DMX – RGB · store · blog.
Contrast with DMX→relay (day 13), Ethernet I/O (day 11) and Modbus TCP (day 12) depending on who owns timing. Tomorrow (day 15): teaser — Mini DMX512 tester. No post URL yet.