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Ethernet I/O Controls: Relays + Digital/Analog Inputs

Ethernet I/O Controls: Relays + Digital/Analog Inputs

So far this blog has lived in DMX and Art-Net territory: universes, IPs, topologies, and nodes such as the TH-2U. That stack moves lights. When the room also needs to start a fan, trip a contactor, open a curtain, or read a wall pushbutton, you leave the DMX map and enter Ethernet I/O: boards with a built-in web server, relays, digital inputs, and—on the fuller model—analog inputs. This guide introduces two ElectroTAS boards — ETHER8R8I3A and ETHER8R— aimed at room automation and light industrial automation. Modbus stays a day-12 teaser only.

What Ethernet I/O is (and what it is not)

An Ethernet I/O controller sits on your LAN and exposes physical I/O through an embedded web panel:

  • Relay outputs: dry contacts that switch a load circuit—service lights, contactor coils, small motors, valves—within the contact voltage/current rating.
  • Digital inputs: on/off sensing for pushbuttons, switches, door contacts, dry sensors.
  • Analog inputs: a voltage within a tight range (on ETHER8R8I3A: 0–3.3 V) for proportional sensors or pots already conditioned to that span.

It does not replace an Art-Net node or a lighting desk. Art-Net carries DMX universes; Ethernet I/O carries room loads and feedback. The networking habits still transfer: one planned IP per device, web panel on the same subnet—see universes & IPs and network topologies.

When you need relays + inputs (vs lights-only Art-Net)

Art-Net / DMX is enough when the job is lighting. Choose USB–DMX or an Ethernet node based on distance and universe count—classic debate: USBDMX vs Art-Net, grounded in what Art-Net is and the TH-2U guide (EN shop: TH-2U).

  • Switch non-DMX loads (extractors, service circuits, contactor coils) within 220 V / 7 A per contact—or pilot a larger contactor.
  • Read local pushbuttons, limit switches, presence contacts.
  • Bring in a 0–3.3 V analog (ETHER8R8I3A only) without standing up a full PLC.
  • Operate from a browser—and on ETHER8R, also from an Android app—without a lighting console.

Many venues run both: Art-Net for show light, Ethernet I/O for “housekeeping” loads and simple feedback.

Mental map: show light vs room loads
  • Art-Net / DMX: console or PC software, lighting switch, node and fixtures.
  • Ethernet I/O: laptop, tablet, or phone on the LAN, switch, ETHER8R or ETHER8R8I3A, relays, pushbuttons and sensors.

Side-by-side: ETHER8R vs ETHER8R8I3A

Both include a built-in web server, 8 relay outputs (220 V, 7 A max per contact), reset and factory-default buttons, a unique MAC, and 20 °C to 50 C operating range. Inputs and recommended PSU differ.

FeatureETHER8RETHER8R8I3A
Web panelYesYes
Relays8 outs, 220 V, 7 A max.8 outs, 220 V, 7 A max.
Digital inputs—8
Analog inputs—3 (0–3,3 V)
Typical consumption300 mA500 mA
Recommended PSU5 V 1 A12 V 1 A
App AndroidYes—

Pick ETHER8R for eight networked relays plus Android control. Pick ETHER8R8I3A when you need local digital feedback and three 0–3.3 V analogs. Shop ETHER8R · Shop ETHER8R8I3A.

Use cases: rooms, buildings, light industry

Rehearsal room / small venue

  • Relays for work lights, “ON AIR signs, extractors, or contactor coils (stay inside 7 A / 220 V or pilot a sized contactor).
  • With ETHER8R8I3A: wall pushbuttons for service scenes without touching the DMX desk.
  • Same documented LAN discipline you use for Art-Net—labeled IPs, no public guest Wi‑Fi.

Building / home automation

  • Irrigation, blinds (via motor/contactor), non-DMX corridor lighting, simple dry-contact alarms.
  • Local web panel; hardware reset / factory default when someone breaks the config.

Light industrial automation

  • Test benches, small lines, machine signaling, basic interlocks on digital inputs.
  • 0–3.3 V analogs for pots or sensors already scaled to that range (we do not claim 4–20 mA or 0–10 V natively).

When you later need Modbus TCP toward a SCADA/PLC, see the Modbus TCP 8R8Ideep dive on day 12.

Diagram: PC or tablet → switch → board → loads / sensors
  • Operator: Browser to the web panel; Android app (ETHER8R only).
  • LAN switch: Operator port; Ethernet I/O board port.
  • Board: PSU per model; 8 relays to loads or contactor coils; ETHER8R8I3A: 8 digital inputs + 3 analog inputs 0–3.3 V.

Wiring and safety: mains, isolation, analogs

Relays switch 220 V at up to 7 A per contact. That is mains energy—not a panel LED.

  • Respect the rating: 220 V / 7 A max. Larger loads: use the board relay to drive a properly sized contactor coil.
  • Keep logic away from load chaos: Ethernet/MCU/inputs share a board with power contacts. Neat wiring, tight terminals; if you are not qualified for 220 V work, hire someone who is.
  • Digital inputs: pushbutton/switch style contacts. Do not feed them 220 V.
  • Analog inputs (8R8I3A only): 0–3.3 V. A 0–10 V or 4–20 mA sensor needs external conditioning.
  • PSU: ETHER8R wants 5 V 1 A; ETHER8R8I3A wants 12 V 1 A. Matching barrels are not interchangeable voltages.
  • Temperature: −20 °C to 50 °C; give sealed racks some airflow.
First-boot checklist for the web panel
  1. Connect the correct PSU (5 V 1 A for ETHER8R; 12 V 1 A for ETHER8R8I3A) and RJ45 to the control switch.
  2. Put your PC/tablet on the same subnet as the board (same habit as Art-Net nodes).
  3. Open the Ethernet controller web panel; identify the unit by MAC / label.
  4. Exercise relays one by one with a safe test load (or status LEDs before mains wiring).
  5. On ETHER8R8I3A: toggle a test pushbutton on a digital input; if needed, apply a known voltage inside 0–3.3 V to an analog channel.
  6. Write IP, relay roles, and input roles on the case or room sheet.
  7. If config is unrecoverable, use factory default and re-document; use reset for clean reboots.

Network habits (same as lighting)

Confirmed specs do not claim VLAN creation or PoE on these boards—they join the LAN you provide.

  • Static IP or reserved DHCP; label every board.
  • Prefer the control/automation switch over venue guest Wi‑Fi.
  • Document which relay drives which load.
  • If you share a backbone with Art-Net, keep separate sheets (universe vs relay) even in the same rack.

Refresh: day 10 (IPs) and day 9 (topologies).

How this sits next to lighting gear

Think of Ethernet I/O as the sibling of your lighting backbone, not a replacement. A fixed install might run a TH-2U for two Art-Net universes while an ETHER8R8I3A handles work lights, an extractor contactor, and door contacts—all on the same documented switch fabric, different worksheets.

Touring kits that still lean on USB–DMX for FOH can add an ETHER8R on venue LAN for house cues without dragging another universe into the soft. The rule of thumb: DMX owns fixtures; relays own contacts and coils within rating.

Labeling discipline matters twice as much when both stacks share a rack: one sticker for Art-Net IP/universe, another for I/O IP/relay map. Factory-default and reset on the Ethernet boards are your recovery path when a weekend tech rewrites the panel; they are not a substitute for a printed room sheet.

FAQ

1. ETHER8R or ETHER8R8I3A?
Eight relays plus Android: ETHER8R. Need eight digital inputs and three 0–3.3 V analogs: ETHER8R8I3A.

2. Can these boards drive DMX fixtures?
No. Use USB–DMX interfaces or the TH-2U. El I/O Ethernet es para relays y entradas de sala.

3. Which power supply?
ETHER8R: 5 V 1 A (2.1 mm). ETHER8R8I3A: 12 V 1 A (2.1 mm). Do not cross them.

4. Will the relays handle any 220 V load?
Up to 7 A per contact. Larger loads need an intermediate contactor. Follow local electrical codes.

5. Do the analogs accept 0–10 V or 4–20 mA?
Confirmed range is 0–3.3 V. Other signal types need external conditioning.

6. Do they need cloud internet?
No. The web panel runs on the LAN. “Ethernet I/O” does not mean “SaaS dependency.”

7. What if I need Modbus TCP?
Shop has a dedicatedModbus TCP 8R8I). That is day 12; this post stays on classic web-panel I/O.

8. Is there a USB relay option?
Yes—the U24R (4 USB relays) for local benches; it does not replace an eight-out Ethernet controller in a fixed install.

CTA and related resources

Building room or light-industrial automation with Ethernet relays and optional digital/analog inputs? Start with ETHER8R8I3A or ETHER8R in the shop ElectroTAS · Automation.

Next on the blog: Modbus TCP applied to Ethernet relay and input controllers—the bridge to SCADA/PLC without leaving the same I/O family.

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