Or: How I Learned to Stop Worrying and Love Industrial IoT
By Patrick Ryan, CTO @ Fireball Industries
"Making industrial automation slightly less painful since whenever I started this company"
Look, I'm not saying this OPC UA Server is over-engineered, but it supports 9 industrial protocols simultaneously. That's right, NINE. Because apparently "just use OPC UA" wasn't enterprise-y enough for 2026.
Is it overkill? Absolutely. Will it save your bacon when some legacy PLC from 1997 insists on MODBUS? Also yes.
┌──────────────────────────────────────────────────────────────────────┐
│ │
│ OPC UA Server Core (Port 4840) │
│ Tag Simulation + Real-time Updates │
│ │
└─────────────────────────┬────────────────────────────────────────────┘
│
│ PublisherManager orchestrates all protocols
│
┌───────────────────┴───────────────────┐
│ │
▼ ▼
┌─────────────┐ ┌────────────────┐
│ INBOUND │ │ OUTBOUND │
│ (Server) │ │ (Clients) │
└─────────────┘ └────────────────┘
│ │
│ │
├─► OPC UA Server ├─► OPC UA Client ⭐ NEW
│ (Clients connect to us) │ (We push to servers)
│ Port: 4840 │ → Ignition
│ │ → Historians
│ │ → Cloud platforms
│ │
├─► MODBUS TCP Server ├─► MQTT Publisher
│ (PLCs poll us) │ (We publish to broker)
│ Port: 502 │ → Cloud (AWS/Azure)
│ Registers: 0-1000 │ → Node-RED
│ │ → IoT platforms
│ │
├─► REST API Server ├─► Sparkplug B Publisher
│ (HTTP clients query us) │ (We publish to broker)
│ Port: 5001 │ → Ignition Edge (native)
│ GET/POST endpoints │ → Cirrus Link
│ │
├─► WebSocket Server ├─► Apache Kafka Producer
│ (Browsers connect to us) │ (We publish to topics)
│ Port: 9001 │ → Data lakes
│ Real-time push │ → Stream processing
│ │
│ └─► AMQP Publisher
│ (We publish to exchange)
│ → RabbitMQ
│ → Enterprise bus
│
└─► Total: 4 Server Modes └─► Total: 5 Client Modes
The Scorecard of Our Protocol Addiction
| # | Protocol | Type | Port | Direction | Use Case | Millennial Translation |
|---|---|---|---|---|---|---|
| 1 | OPC UA Server | Server | 4840 | ← Inbound | SCADA systems connect | "Y'all can read my data" |
| 2 | OPC UA Client ⭐ | Client | N/A | → Outbound | Push to Ignition, historians | "I'm sliding into your DMs" |
| 3 | MQTT | Client | N/A | → Outbound | IoT/cloud brokers | "Publishing my thoughts online" |
| 4 | Sparkplug B | Client | N/A | → Outbound | Ignition Edge native | "Speaking Ignition's language" |
| 5 | Apache Kafka | Producer | N/A | → Outbound | Enterprise streaming | "Screaming into the void (at scale)" |
| 6 | AMQP | Publisher | N/A | → Outbound | RabbitMQ messaging | "Enterprise-grade texting" |
| 7 | WebSocket | Server | 9001 | ← Inbound | Real-time browsers | "Live streaming my data" |
| 8 | REST API | Server | 5001 | ← Inbound | HTTP GET/POST | "The API everyone understands" |
| 9 | MODBUS TCP | Server | 502 | ← Inbound | Legacy PLCs poll | "Talking to grandpa's PLC" |
| 10 | GraphQL | Server | 5002 | ← Inbound | Modern query interface | "REST but you pick the fields" |
| 11 | InfluxDB | Client | N/A | → Outbound | Time-series database | "Remembering everything forever" |
| 12 | Alarms | Monitor | N/A | → Outbound | Notifications | "Screaming when things break" |
Tag Update: Temperature = 25.5°C
│
├─► OPC UA Server (Port 4840)
│ └─► UaExpert reads value
│
├─► OPC UA Client ⭐
│ ├─► Writes to Ignition server (ns=2;s=Gateway/Temperature)
│ ├─► Writes to Historian (ns=1;s=Plant/Temp)
│ └─► Writes to Cloud server (ns=1;s=Devices/Edge001/Temp)
│
├─► MQTT Publisher
│ └─► Publishes to industrial/opcua/Temperature
│ ├─► Node-RED subscribes
│ ├─► AWS IoT Core receives
│ └─► Azure IoT Hub receives
│
├─► Sparkplug B Publisher
│ └─► Publishes DDATA message
│ └─► Ignition MQTT Engine receives
│
├─► Apache Kafka Producer
│ └─► Publishes to industrial-data topic
│ ├─► Kafka Streams processes
│ └─► Data lake ingests
│
├─► AMQP Publisher
│ └─► Publishes to industrial.data exchange
│ └─► RabbitMQ routes to queues
│
├─► WebSocket Server (Port 9001)
│ └─► Broadcasts to connected browsers
│ └─► Dashboard updates in real-time
│
├─► REST API (Port 5001)
│ └─► Stores in memory
│ └─► Responds to HTTP requests
│
└─► GraphQL API (Port 5002)
└─► Stores in memory
└─► Responds to GraphQL queries
└─► GraphiQL IDE available
│
└─► InfluxDB Publisher
└─► Writes to time-series database
└─► Grafana visualizes data
└─► Historical analysis available
│ └─► GET /api/tags/Temperature returns value
│
└─► MODBUS TCP Server (Port 502)
└─► Stores in registers 0-1 (float = 2 registers)
└─► PLC polls holding registers
Goal: Complete Ignition ecosystem integration
Your Server
├─► OPC UA Client → Ignition OPC UA Server (write tags)
└─► Sparkplug B → Ignition MQTT Engine (SCADA protocol)
Ignition connects via:
├─► OPC UA Client → Your OPC UA Server (read tags)
└─► Designer → Your REST API (monitoring)
Configuration:
{
"publishers": {
"opcua_client": {
"enabled": true,
"servers": [{
"url": "opc.tcp://ignition:4841",
"namespace": 2,
"base_node": "ns=2;s=Gateway/"
}]
},
"sparkplug_b": {
"enabled": true,
"broker": "ignition",
"port": 1883,
"group_id": "Sparkplug B Devices"
}
}
}Goal: Log to multiple historians for redundancy
Your Server
├─► OPC UA Client
│ ├─► Primary Historian (OSIsoft PI)
│ └─► Backup Historian (Canary)
└─► Kafka Producer → Enterprise data lake
Configuration:
{
"publishers": {
"opcua_client": {
"enabled": true,
"servers": [
{
"url": "opc.tcp://pi-server:4840",
"name": "Primary PI",
"node_mapping": {
"Temperature": "ns=1;s=Plant.Area1.Temp"
}
},
{
"url": "opc.tcp://canary:4840",
"name": "Backup Canary"
}
]
},
"kafka": {
"enabled": true,
"topic": "historian-backup"
}
}
}Goal: Push from factory floor to cloud platforms
Factory Floor
│
└─► Your Server (Edge Gateway)
├─► OPC UA Client → Cloud OPC UA Server
├─► MQTT → AWS IoT Core
├─► Kafka → Cloud Kafka Cluster
└─► WebSocket ← Cloud dashboard
Configuration:
{
"publishers": {
"opcua_client": {
"enabled": true,
"servers": [{
"url": "opc.tcp://cloud.company.com:4841",
"username": "edge-device-001",
"password": "${CLOUD_PASSWORD}"
}]
},
"mqtt": {
"enabled": true,
"broker": "mqtt.cloud.com",
"port": 8883,
"use_tls": true
}
}
}Goal: Bridge modern and legacy systems
Modern Systems
├─► Your OPC UA Server ← SCADA reads via OPC UA
└─► Your REST API ← Web dashboard reads via HTTP
Legacy Systems
└─► Your MODBUS TCP Server ← Old PLC polls via MODBUS
Configuration:
{
"publishers": {
"modbus_tcp": {
"enabled": true,
"port": 502,
"register_mapping": {
"Temperature": {"register": 0, "type": "float"}
}
},
"rest_api": {
"enabled": true,
"port": 5001
}
}
}Goal: Local testing with all protocols
Your Server (localhost)
├─► OPC UA Server (4840) ← UaExpert connects
├─► OPC UA Client → Test server (4841)
├─► MQTT → Local Mosquitto (1883)
├─► WebSocket (9001) ← Browser connects
├─► REST API (5001) ← Postman tests
└─► MODBUS TCP (502) ← QModMaster polls
Configuration:
{
"publishers": {
"opcua_client": {"enabled": true},
"mqtt": {"enabled": true},
"websocket": {"enabled": true},
"rest_api": {"enabled": true},
"modbus_tcp": {"enabled": true}
}
}✅ Use when:
- Pushing to Ignition's OPC UA server
- Writing to historians (PI, Canary)
- Edge-to-cloud OPC UA connectivity
- Data replication to multiple OPC UA servers
- Centralized OPC UA server aggregation
❌ Don't use when:
- Need publish/subscribe (use MQTT instead)
- Need high-throughput streaming (use Kafka)
- Target doesn't support OPC UA
✅ Use when:
- IoT cloud platforms (AWS IoT, Azure IoT)
- Node-RED workflows
- Lightweight messaging
- Publish/subscribe needed
- Mobile app connectivity
❌ Don't use when:
- Need guaranteed delivery (use AMQP)
- Need high throughput (use Kafka)
- Target expects OPC UA
✅ Use when:
- Ignition Edge (primary use case)
- Need birth/death certificates
- Need store-and-forward
- SCADA-specific features needed
❌ Don't use when:
- Target doesn't support Sparkplug B
- Standard MQTT is sufficient
✅ Use when:
- High-throughput streaming
- Data lake ingestion
- Stream processing pipelines
- Enterprise microservices
- Event sourcing
❌ Don't use when:
- Simple messaging (use MQTT)
- Request/response needed (use REST)
- Low-volume data
✅ Use when:
- Legacy PLCs need to poll data
- SCADA systems expect MODBUS
- Industrial HMIs use MODBUS
- Vendor tools require MODBUS
❌ Don't use when:
- Modern protocols available
- Need event-driven (MODBUS is poll-based)
✅ Use when:
- Web applications
- Mobile apps
- Simple HTTP clients
- Periodic polling acceptable
- No persistent connection needed
❌ Don't use when:
- Need real-time push (use WebSocket)
- High-frequency updates (overhead)
| Protocol | Latency | Throughput | CPU Usage | Best For |
|---|---|---|---|---|
| OPC UA Server | 5-20ms | Medium | Low | SCADA clients |
| OPC UA Client | 10-50ms | Medium | Low | Push to servers |
| MQTT | 5-30ms | High | Low | IoT/cloud |
| Sparkplug B | 5-30ms | High | Low | Ignition Edge |
| Kafka | 10-100ms | Very High | Medium | Streaming |
| AMQP | 10-50ms | High | Medium | Enterprise |
| WebSocket | 5-20ms | Medium | Low | Web browsers |
| REST API | 20-100ms | Low | Low | HTTP clients |
| MODBUS TCP | 50-200ms | Low | Low | Legacy PLCs |
┌─────────────────────────────┐
│ Your OPC UA Server │
│ (All protocols enabled) │
└──────────────┬──────────────┘
│
┌──────────────────────────┼──────────────────────────┐
│ │ │
▼ ▼ ▼
┌──────────┐ ┌──────────┐ ┌──────────┐
│ Ignition │ │ Cloud │ │ Legacy │
│ (OPC UA │ │ (MQTT) │ │ PLC │
│ Client) │ │ │ │ (MODBUS) │
└──────────┘ └──────────┘ └──────────┘
Factory Floor Edge Gateway Cloud
│ │ │
├─► PLC 1 ──┐ │ │
├─► PLC 2 ──┼─► MODBUS ──────┤ │
└─► PLC 3 ──┘ │ │
│ │
┌───────┴────────┐ │
│ Your Server │ │
│ (Multi-Proto) │ │
└───────┬────────┘ │
│ │
├─► OPC UA Client ─────┼─► Cloud OPC UA
├─► MQTT ──────────────┼─► AWS IoT
└─► Kafka ─────────────┼─► Data Lake
│ │
Local Network │
│ │
Ignition Server │
(Reads via OPC UA) │
The Part Where We Pat Ourselves on the Back
🎉 9 Industrial Protocols:
- OPC UA Server (original) - The foundation
- OPC UA Client ⭐ NEW - The plot twist
- MQTT - The IoT darling
- Sparkplug B - Ignition's BFF
- Apache Kafka - The enterprise flex
- AMQP/RabbitMQ - The reliable one
- WebSocket - The real-time enabler
- REST API - The people's champion
- MODBUS TCP - The legacy legend
What This Thing Can Actually Do
✅ Server mode (4 protocols) - Others connect to you (popular kid energy)
✅ Client mode (5 protocols) - You push to others (aggressive networking)
✅ Bidirectional OPC UA - Server + Client (identity crisis resolved)
✅ Multi-cloud - AWS, Azure, Google (cloud-agnostic and proud)
✅ Multi-SCADA - Ignition, Wonderware, etc. (doesn't play favorites)
✅ Legacy support - MODBUS TCP (respecting the ancients)
✅ Modern web - WebSocket + REST (keeping up with the times)
✅ Enterprise - Kafka + RabbitMQ (resume fodder)
The "Why Did We Build This?" Answer Sheet
✅ Ignition Edge integration (complete) - The main event
✅ Historian logging (PI, Canary) - For compliance and paranoia
✅ Cloud platforms (AWS, Azure) - Buzzword compliance achieved
✅ Legacy PLC bridging - Bringing grandpa's hardware to the party
✅ Data lake ingestion - Lake of data, ocean of possibilities
✅ Real-time dashboards - Making stakeholders happy since 2025
✅ IoT gateway scenarios - Edge computing with extra steps
✅ Enterprise data bus - Because "integration" sounds professional
You now have a complete industrial gateway capable of bridging any protocol to any other protocol! 🚀
Now go forth and integrate all the things. Or take a nap. Both are valid choices.
-Patrick Ryan, CTO @ Fireball Industries
"Making industrial automation slightly less painful, one protocol at a time"