Modbus TCP on ElectroTAS Controllers: Industrial Integration

In day 11 we covered Ethernet I/O boards with a built-in web panel: ETHER8R and ETHER8R8I3A. Those shine when people drive relays and read inputs from a browser (or the Android app on the 8R) without standing up a full SCADA stack. Today we move to Modbus TCP — the dialect many PLCs, HMIs, and SCADA systems expect on industrial Ethernet. The focus product is ElectroTAS’s

: eight relays, eight digital inputs, and a configurable web server aimed at ETHER ModBus 8R8I .industrial integrationIf you arrive from show lighting, keep what you already know: Art-Net still moves DMX universes; Modbus TCP moves

. They can share a plant when the network stays orderly — the same IP and switch habits from automation points and day 10 . day 9 topologies.

What Modbus TCP is (without inventing register maps)

Modbus TCP. On a real plant floor:Ethernet / TCP-IPCompared with a human-only web panel, Modbus TCP lets the supervisor treat the board as

• A client (historically “master”) starts the conversation — typically your SCADA, PLC, or HMI.
• A server (historically “slave”) answers — here, the ElectroTAS board exposing field I/O.
• Data lives in Modbus’s abstract model: coils (discrete bits) and registers (16-bit values). That is the protocol vocabulary, not a product-specific address book.

: tags, alarms, recipes, historians. The web server still helps commissioning; production contracts usually ride the Modbus client.another citizen on the plant bus this article does

Critical: publish invented register maps or function-code tables “for this board.” Concrete addressing (which coil or register maps to which relay or input) comes from the product documentation and ElectroTAS support. Integrators must use that official source — not a generic internet example and not anything fabricated here.notNot every industrial job needs Modbus. Sometimes the day-11 web-panel boards are the right tool — and forcing Modbus “because it sounds more industrial” only adds engineering cost.

When you need Modbus TCP (and when a web panel is enough)

Quick decision table (no invented extras):

• Web panel is enough when operators open a browser, toggle relays by hand, read inputs on the same LAN, and no SCADA/PLC must own those points as official tags.
• Modbus TCP belongs when the supervisory system already speaks Modbus (or the client requires it): plant tags in SCADA, PLC logic, HMI screens, centralized alarms, historians.
• Same physical I/O family, different software contract: 220 V / 7 A relays and digital inputs are still contacts and signals; what changes is how plant software consumes them.
• Honest hybrid: many sites start with a web panel in the lab and move to a Modbus client when SCADA arrives on site. Pick the product for the final contract, not for day-one demo convenience.

Practical summary: if the deliverable is “the electrician opens a browser and starts the extractor,” stay with day 11. If the deliverable is “SCADA writes the tag and the PLC reads the interlock,” this is your post.

Need	Web-panel line (day 11)	ETHER ModBus 8R8I
Operate from a browser	Yes (both); Android app on ETHER8R	Yes (configurable web server)
SCADA / PLC / HMI client over Modbus TCP	Not the focus of those models	Yes — Modbus-primary design
8 relays at 220 V / 7 A	Yes	Yes
Digital inputs	8 on ETHER8R8I3A; none on ETHER8R	8
Analog inputs 0–3.3 V	3 on ETHER8R8I3A	—
Power	5 V 1 A (8R) / 12 V 1 A (8R8I3A)	12 V (~500 mA)

The

Product deep-dive: ETHER ModBus 8R8I

is ElectroTAS’s Modbus TCP Ethernet controller with ETHER ModBus 8R8I and eight relay outputs. It targets industrial rooms where a Modbus TCP client must read status and command loads, with a eight digital inputs for commissioning.configurable web serverShop EN:

Feature	Confirmed value
Model	ETHER ModBus 8R8I
Integration protocol	Modbus TCP (Ethernet)
Web server	Built-in, configurable
Relays	8 outputs, 220 V, 7 A max
Digital inputs	8
Buttons	Reset + factory default
Network identity	Unique MAC address

Power supply 12 V Typical current ~500 mA Operating temperature −20 °C to 50 °C Weight / dimensions 195 g · 153×110×25 mm Package Board

. Category: ETHER ModBus 8R8I. Web-panel contrast: Automation (8R+8I+3A) and ETHER8R8I3A (8R + Android app). ETHER8R What we

claim here: coil/register maps, specific function codes, PoE, analog inputs, an Android app, GPIO maps, serial baud rates, or any undocumented feature. Need project-level addressing? Ask ElectroTAS for the official docs.do notThe pattern is easy to sketch and hard to fake in documentation:

Integration patterns: SCADA, PLC, and HMI

If the same site also runs show lighting, the Ethernet backbone can be shared or segregated by policy — the non-negotiable is orderly addressing. Art-Net context remains in

1. The client (SCADA / PLC / HMI) opens a Modbus TCP session to the board’s IP.
2. The board answers as a server: digital inputs are read; relays are commanded/read according to the official product map.

, 220 V, and the

.

Modbus TCP does not forgive a chaotic LAN. The same rules you apply to Art-Net nodes apply here: what Art-Net isNo need to reinvent topologies: day 9 already covered stars and backbones; day 10 covered universe and IP habits. Bring that checklist into automation. USB–DMX vs Art-Net The relays switch TH-2U guide.

Network hygiene: same as Art-Net, different protocol

per contact. That is mains power, not a panel LED.

• Fixed IP or documented DHCP per device; label switch port and MAC.
• Segregate guest Wi‑Fi for the public / visitors away from the control network.
• A decent switch on the control backbone; avoid hubs and “magic adapters” without a plan.
• Firewall / ACL when plant policy requires it: the Modbus client talks to the board IP, not to the whole internet.

Not necessarily. The configurable web server helps commissioning and checks; Modbus TCP is the contract toward SCADA/PLC/HMI. Different roles, often used together.

Electrical safety: 220 V relays, inputs, and 12 V power

Day 11 presented ETHER8R / ETHER8R8I3A as 7 A controls. If the requirement is an industrial Modbus TCP client, the natural path is the 1. Does Modbus TCP replace the ETHER ModBus 8R8I web panel?.

• Respect the rating: if the load exceeds 7 A / 220 V, use the board relay to pilot a properly sized contactor coil — not the load directly.
• Digital inputs: meant for contact / field logic signals — do not feed them 220 V.
• 12 V supply: power the board as specified (~500 mA typical draw). Undersized adapters and “whatever fits the barrel” are not a plan.
• Temperature: −20 °C to 50 °C; give closed cabinets reasonable airflow.
• Mains work: if you are not qualified for 220 V wiring, hire someone who is. Reset and factory-default buttons recover configuration — they do not fix unsafe cabling.
• Terminal order: visually separate power (relay contacts) from logic (inputs, Ethernet, 12 V). A clean rack prevents the next incident.

From the Modbus TCP client (SCADA/PLC/discovery tool), confirm the server answers at the board IP — do not assume coil/register addresses: use the official product map.

Exercise one relay and one digital input on the bench (safe load / dry contact) before plant 220 V wiring.

Document IP, physical location, and SCADA tags. Know reset and factory default if you need a clean config restore.

Only then integrate real loads and supervisor alarms.

FAQ

web-panel
Pilot a contactor with the board relay. Do not push the contact past 220 V / 7 A.

3. Where is the register / coil map for this board?
The ModBus 8R8I datasheet confirms a configurable web server; we do not list an Android app for this model.We do not invent it in the blog. Later in the roadmap, the ETHER ModBus 8R8I.

4. Does it include analog inputs or PoE?
8 relays + 8 digital inputsIf your plant already speaks

12 V
, the 5. Can Art-Net and Modbus share a LAN? puts eight relays and eight digital inputs into that conversation — with a web server for a clean start and the same network discipline you already use for show and industry. Shop: 6. What if my load exceeds 7 A? ·

7. Is there an Android app like ETHER8R?
·

8. What about USB relays on the lab bench?
·

Modbus TCP
.

ETHER ModBus 8R8I
teaser — U24R : when the lighting universe also needs to fire contacts. No post URL yet. Later, local USB control with the U24R.

Wrap-up and next step

If your plant already speaks Modbus TCP, the ETHER ModBus 8R8I puts eight relays and eight digital inputs into that conversation — with a web server for a clean start and the same network discipline you already use for show and industry. Shop: ETHER ModBus 8R8I · Automation · store · blog.

Tomorrow (day 13): teaser — DMX to 1 relay / 8 relays: when the lighting universe also needs to fire contacts. No post URL yet. Later, local USB control with the U24R.