End-to-End Architecture

How Data Flows from PLC Registers to MQTT

A robust, non-intrusive architecture that polls factory controllers on local plant LANs and streams structured JSON payloads to cloud brokers without compromising OT air-gapped security.

// Field-to-Cloud Telemetry Flowchart

1 Plant Floor Controllers

Direct socket drivers read registers over local industrial Ethernet (no intermediate OPC server required).

Modbus TCP MELSEC SLMP Siemens S7 Omron FINS

2 Techfics Edge Gateway

Sub-50ms polling loop, byte/word swap, deadband filtering, and encrypted SQLite disk buffer spooling.

32-bit Float Big/Little Endian swap
Change-of-State / Deadband filters
Node-Locked AES-256 IP Shield

3 Secure Telemetry Stream

Outbound-only encrypted pipeline. Zero inbound open ports on plant firewall; automatic reconnect backoff.

TLS 1.3 / mTLS MQTT Sparkplug B REST / Webhook

4 Brokers & Platforms

Consume real-time telemetry across enterprise SCADA, analytics engines, ERP/MES databases, and dashboards.

EMQX / HiveMQ AWS IoT Core TimescaleDB / SQL

⚡

Sub-50ms Polling Latency

Optimized asynchronous socket loops query dozens of registers in parallel, eliminating the multi-second lag typical of legacy OPC-DA/UA wrapper bridges.

🛡️

Air-Gapped Store-and-Forward

If the factory internet or corporate WAN disconnects, telemetry queues safely to encrypted local SQLite disk storage and backfills automatically upon reconnect.

🔐

Edge IP & Runtime Hardening

Gateway runtime is hardened with PyArmor AES-256 bytecode encryption and hardware MAC/UUID node-locking, preventing unauthorized tampering on customer IPCs.

Protocol Matrix

Supported Industrial Hardware & Protocols

Native drivers written directly in high-performance socket layers without requiring third-party licensing or heavy runtime dependencies.

Protocol / Standard	Supported Hardware Families	Accessible Memory & Register Areas	Data Types Handled
Modbus TCP / RTU	Schneider Electric, WAGO, Delta, Advantech ADAM, Moxa, Phoenix Contact	Holding Registers (40001+), Input Registers (30001+), Coils (00001+), Discrete Inputs (10001+)	INT16, UINT16, INT32, UINT32, Float32 (Big/Little Endian swap), Bitmasks
Mitsubishi MELSEC (SLMP)	MELSEC iQ-R, iQ-F (FX5U), Q-Series, L-Series (MC Protocol 3E / 4E Frames)	D (Data Registers), W (Link Registers), R / ZR (File Registers), M (Internal Relays), X/Y (I/O)	16-bit Words, 32-bit DWords, 64-bit Double, BCD, Single-bit flags
Siemens S7 (RFC 1006)	Siemens S7-1200, S7-1500, S7-300, S7-400 (ISO-on-TCP direct socket)	DB (Data Blocks), M (Merker memory), I (Digital Inputs), Q (Digital Outputs), Timer/Counter	Real, DInt, Int, Word, DWord, Byte, Boolean bit offsets
Omron FINS (TCP/UDP)	Omron CJ2, CS1, CP1H, CP1L, NJ/NX Series (via FINS gateway bridge)	DM (Data Memory), CIO (Core I/O), WR (Work Area), HR (Holding Area)	16-bit Signed/Unsigned, Float32 IEEE-754, Hexadecimal channels

Dynamic Configuration

Human-Readable Tag & Polling Declarations

Define holding registers, SLMP blocks, and Siemens DB tags in clean JSON or YAML schema. The gateway loads configurations dynamically with hot-reload capabilities, meaning tag additions never require stopping plant production lines.

Deadband Filtering: Only publish MQTT payloads when value variance exceeds user threshold (e.g. ≥ 0.5°C).
Endianness Control: Configure word swap (AB CD vs CD AB) per tag for non-standard 32-bit industrial transmitters.
Scale Multipliers: Convert raw integer counts to engineering units (e.g. raw 4000 counts → 40.00 PSI).

            // gateway_tags.json - Dynamic Register Definition

            {

              "node_id": "line_03_sintering_furnace",

              "protocol": "modbus_tcp",

              "ip_address": "192.168.1.50",

              "port": 502,

              "poll_interval_ms": 50,

              "tags": [

                {

                  "name": "zone1_temp_celsius",

                  "register_type": "holding",

                  "address": 40102,

                  "data_type": "float32",

                  "word_swap": true,

                  "scale": 0.1,

                  "deadband": 0.25

                },

                {

                  "name": "press_cycle_active",

                  "register_type": "coil",

                  "address": 00014,

                  "data_type": "boolean"

                }

              ]

            }

            // Outbound MQTT Payload (JSON Envelope)

            {

              "topic": "factory/kl/line03/telemetry",

              "ts": 1728812490150,

              "gateway_id": "TF-GW-04",

              "status": "ONLINE",

              "metrics": {

                "zone1_temp": 1420.4,

                "press_pressure_bar": 210.8,

                "cycle_count": 84291,

                "error_code": 0

              },

              "buffered": false

            }

Resilient Edge Storage

Zero Telemetry Loss During Network Outages

In industrial automation, loss of telemetry during an internet dropout breaks batch traceability records and invalidates ISO/FDA audit trails.

The Techfics Edge Gateway operates an autonomous, transactional local SQLite circular buffer. If connection to the remote MQTT broker drops:

Instant Fallback: Polled registers continue saving locally with microsecond-precision hardware timestamps.
Auto-Replay: Once the outbound network recovers, the gateway replays buffered telemetry in FIFO sequence with a `buffered: true` flag.
Disk Throttling: Configurable retention caps (e.g. 500,000 events) prevent edge IPC flash memory exhaustion.

Field-Proven Industrial Deployment

Case Study: Cleanroom Production Control for Maruwa Malaysia & Japan

Discover how Techfics deployed air-gapped shop-floor edge nodes, automated 2D QR batch travelers, and PLC telemetry lockouts for Tokyo Stock Exchange-listed precision manufacturer Maruwa (TSE: 5344), achieving 100% batch traceability and sub-15s audit queries.

Read Maruwa Case Study →

Engineering FAQs

Frequently Asked Technical Questions

Practical answers for plant automation engineers, OT leaders, and industrial software architects.

Can the gateway operate in a completely air-gapped factory without internet?

Yes. The gateway can publish to an on-premises MQTT broker (e.g. EMQX or Mosquitto installed on the local plant server) or stream directly to local SQL Server / PostgreSQL databases. Zero external internet connectivity is required.

How does the gateway handle 32-bit floating point byte ordering?

Standard Modbus transmits 16-bit words. When reading 32-bit floats, manufacturers use varying endianness formats (Big-Endian `AB CD`, Little-Endian `CD AB`, Mid-Big `BA DC`, or Mid-Little `DC BA`). Our configuration schema includes a per-tag `word_swap` and `byte_swap` boolean flag, converting values accurately to standard IEEE-754 floats.

Can it run alongside existing Kepware / SCADA systems without conflicts?

Yes. Modern industrial PLCs (Siemens S7, MELSEC, Modbus Ethernet couplers) support multiple concurrent TCP socket connections (typically 8 to 64 sockets). Techfics Edge Gateway operates on a dedicated TCP connection, co-existing harmoniously with Kepware, Ignition, or existing Wonderware HMIs.

What hardware does the gateway run on?

The gateway is lightweight and cross-platform. It runs reliably on industrial DIN-rail IPCs (Advantech, Moxa, Siemens Microbox), Raspberry Pi CM4 industrial carriers, standard Linux VMs (Ubuntu/Debian), or Windows Server environments.

Ready to Connect Your Factory Equipment?

Schedule a 30-minute technical demonstration with our industrial systems engineers. We will review your PLC register addresses and test live telemetry streaming.

Schedule 30-Min IIoT Demo Explore Custom ERP & CMMS

Bridging Shop-Floor PLCs To MQTT & Cloud Telemetry