DMX to 1 Relay and 8 Relays: Automating Loads from the Console

In  day 12 we covered Modbus TCP and SCADA — relays driven by an industrial client. In day 11, the path was an Ethernet web panel. Today the trigger is different: the lighting console and the DMX universe. When the show needs fog, motors, work lights, curtains, or effects fired as DMX channels alongside fixtures, ElectroTAS’s  D21R  (1 relay) and D28R  (8 relays) converters step in.

The idea is straightforward: the operator does not open a browser or a PLC — they move a fader or fire a cue, and a DMX channel changes a contact state. Same language you already use for movers and LED. Shop category:  DMX – Relay.

Why fire relays from DMX (instead of Ethernet I/O or Modbus)

Ethernet I/O and Modbus are not “wrong.” They are different contracts:

• Web panel / Ethernet I/O (day 11): a human (or light automation) drives relays from a browser on the LAN.
• Modbus TCP (day 12): SCADA, PLC, or HMI as the industrial client.
• DMX → relay (today): the lighting universe is master. The fog cue sits next to the wash cue. The lighting director fires loads without leaving the console.

Choose DMX→relay when show timing lives in the console, when the lighting crew already owns the DMX patch, and when you refuse to add another software layer just to close a contact. If the plant already lives in SCADA, go back to day 12. If the electrician operates from a notebook browser, day 11. If the show lives in DMX cues, stay here.

How it fits the universe: DMX channel, not an invented map

Conceptually, one or more DMX channels drive relay state (open/closed depending on how you wire NO/NC and program the cue). That is enough to design the show: patch, base address, and a bench test.

Critical: this article does not publish invented addressing tables or “per-model channel maps.” Concrete address, thresholds, and Automatic vs DMX behavior come from the official manual shipped with the board and from ElectroTAS support. Use that source — not a generic internet example and not anything fabricated here.

If your console arrives over Art-Net to a node and then to DMX512, the relay hangs on the DMX leg like any other fixture. Useful context: what Art-Net is, USB–DMX vs Art-Net y la TH-2U guide.

Producto: D21R — Conversor DMX a 1 Relay

The D21R is the compact choice when you need a single contact triggered from DMX: one fog machine, a service cut, a small motor within rating, an auxiliary signal. Ideal for adding “one effect channel” without filling a rack of I/O.

Shop ES: D21R. Shop EN: D21R (EN).

Producto: D28R — Conversor DMX a 8 Relay

The D28R scales the same contract to eight contacts: multiple effect machines, zone cuts, curtain motors, and work lights on the same universe. Same DMX→relay philosophy, more density for a show or fixed install with several synchronized triggers.

Shop ES: D28R. Shop EN: D28R (EN).

How to wire the load: NO, NC, and the contactor

The board does not magically power the equipment: it switches a contact. Choose NO (normally open) if you want the load off until the cue; choose NC (normally closed) if your safety logic needs the opposite state. The decision is electrical and operational, not just software.

• NO: open circuit at rest; closes when the relay acts.
• NC: closed circuit at rest; opens when the relay acts.
• Contactor: for loads or currents beyond direct contact use, use the relay to drive the contactor coil.

Flujo de trabajo: del patch al contacto

1. Define which load you want to trigger and whether D21R or D28R is appropriate.
2. Reserve DMX channels for automation and document them in the patch.
3. Connect the console, DMX universe, and board according to the official manual.
4. Test without a load first: verify Power, DMX signal, mode, and relay actuation.
5. Wire NO or NC to the load, or to a contactor coil where appropriate.
6. Program cues and faders with safe timings; test the full show before opening doors.

Checklist de puesta en marcha

• Is the 12 V DC supply correctly sized?
• Does the DMX bus have correct polarity, termination, and wiring?
• Does the reserved channel avoid overlap with another fixture?
• Does the load stay within 220 V / 7 A, or is it controlled by a contactor?
• Does the NO/NC rest state match your safety criterion?
• Did you test signal loss and recovery before the show?

Preguntas frecuentes

Do I need a PLC?

Not necessarily. If the sequence belongs to the show, the DMX console can be the master. If you need industrial logic, recipes, histories, or complex interlocks, consider PLC/SCADA and the day 12 Modbus approach.

Can I connect any 220 V load?

No. Check voltage, current, load type, and rating. The published figure is 7 A; for motors, heating, or inductive loads consult a professional and use a contactor/appropriate protection.

D21R or D28R?

D21R for one specific contact; D28R when you want eight outputs in the same device and universe. The choice depends on load count, space, power, and show documentation.

Where do I find the exact addressing?

In the official manual supplied with the board and through ElectroTAS support. Do not use a generic table: Automatic/DMX mode, thresholds, and address must be checked for your unit.

Conclusion

DMX does more than move lights: it can also trigger contacts to integrate fog, curtains, motors, work lights, and other effects into the cue language. With D21R for one relay or D28R for eight, the console retains the show’s timing control and the installation keeps a clear boundary between DMX signal and electrical load.

Document the patch, test without a load, respect the 7 A limit, and use a contactor where appropriate. To buy or ask questions, visit ElectroTAS.