Analysis of Three Major Development Trends of PLC Technology — 2026 Update
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What are the major development trends in PLC technology?
Four trends have reshaped PLC platforms since 2024: edge AI (AI-assisted engineering tools and on-device inference are now standard procurement criteria), OPC UA over TSN plus MQTT/Sparkplug B as the de-facto factory data backbone, IEC 62443 cybersecurity as a procurement gate (signed firmware, role-based access, zone-and-conduit architecture), and the convergence of soft-PLC and virtual PLC runtimes that decouples control logic from specific hardware. The 2024 framing of "smaller, networked, programmable" still holds but now reads as baseline rather than trend.
This page was first published in 2024 covering three broad trends (compact hardware, industrial networking, richer programming languages). The 2026 update replaces that framing with the four specific trends below and adds the soft-PLC convergence axis the original missed.
Trend 1: Edge AI and on-device inference
AI-assisted engineering tools (code completion, review assistants in Studio 5000, TIA Portal and GX Works3) are now shipping features rather than slideware. On the analytics side, current mid-range and flagship CPUs run anomaly detection, vibration FFT and motor-current signature analysis directly on the controller, publishing results over MQTT or OPC UA without a separate gateway. This means procurement specifications now name AI capability as a criterion, not a bonus.
Trend 2: OPC UA over TSN and MQTT
OPC UA Pub/Sub over time-sensitive networking has moved from emerging to shipping on mainstream flagships: ControlLogix 5580, S7-1500, iQ-R and M580 all expose it as a first-class protocol. On the northbound side, MQTT with the Sparkplug B payload convention has replaced vendor-specific telemetry links for new installations; most current PLCs ship with a built-in MQTT client. Wireless for mobile assets is shifting from industrial Wi-Fi toward private 5G campus networks. The information-model side is standardising too: OPC UA Companion Specifications (EUROMAP, ADI, Weighenstephan) replace vendor-specific tag structures.
Source: IEC and IEEE standards publications; manufacturer documentation for TSN-capable controller families.
Trend 3: IEC 62443 cybersecurity
Cybersecurity moved from a footnote to a procurement gate. Three forces pushed it: OT incident frequency (including the 2024 ransomware wave against water utilities), the EU NIS2 directive taking effect, and the publication of IEC 62443-4-2 component-level certification guidance. What buyers now expect on every new PLC quote: IEC 62443-4-1 process certification at the vendor and 4-2 at the component, signed firmware with secure boot, role-based access with multi-factor authentication for remote access, zone-and-conduit network architecture, and a documented software bill of materials with patch cadence.
For legacy installed bases (SLC 500, S7-300, MELSEC-Q, Modicon Quantum), component-level certification is limited to newer firmware revisions. The strategy for legacy hardware is isolation (separate VLAN, no internet route) rather than a controller-level fix.
Bonus: soft-PLC and vPLC
Soft-PLC (an IEC 61131-3 runtime on an industrial PC, from vendors including Beckhoff, CODESYS, Siemens and Schneider) and virtual PLC (a containerised control runtime on a hypervisor) have moved from niche to mainstream. Why it matters: the same control program can be redeployed to a different host when the original hardware reaches end of life; the spare-parts strategy simplifies to one industrial PC; and IT-style DevOps (Git version control, CI/CD, container images) becomes feasible inside OT with disciplined change control. For customers migrating from EOL systems, a soft-PLC target is often the cleanest landing pad that also reaches OPC UA over TSN, edge AI and modern cybersecurity in the same project.
What changed since 2024
| Topic | 2024 framing | 2026 reality |
|---|---|---|
| Hardware | Compact, integrated | Compact + edge AI accelerator + TSN port on the same module |
| Communication | Multiple protocols | OPC UA over TSN + MQTT/Sparkplug B + 5G coexistence |
| Programming | Advanced languages | IEC 61131-3 updated edition + AI-assisted engineering |
| Cybersecurity | Footnote | IEC 62443-4-1/4-2, signed firmware, zone-and-conduit |
| Soft-PLC | Not mentioned | Default for new greenfield OT builds |
Scroll the table horizontally to view all columns.
Source: manufacturer documentation and IEC standards publications. Confirm current feature availability per CPU model.
Common questions
Do I need all four trends on every project?
No. The trends are directions, not requirements. Match them to the application: a discrete machine may need none of the edge or AI features; a process line feeding a historian needs OPC UA and MQTT from day one; a regulated environment needs the IEC 62443 baseline regardless.
Is TSN worth specifying now?
For greenfield lines with mixed traffic (motion, safety, data on one network), yes: TSN-enabled controllers are shipping on real lines. For retrofit or small-machine projects, the existing fieldbus remains adequate. TSN switch management adds engineering effort that must be budgeted.
What is the simplest way to start with soft-PLC?
Identify one non-critical application as a pilot, choose a runtime platform that matches the plant's existing programming standard (CODESYS for multi-vendor, vendor-native for single-brand sites), and run it alongside the existing hardware before committing a production line.
Sourcing help
Planning a 2026 PLC upgrade or migration? Send the BOM (current and target hardware) for one quote covering active stock, EOL stock and cross-references across the nine core brands.
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