PLC Reliability in 2026: IEC 61709 MTBF & 62443-4-2
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PLC Reliability in 2026: IEC 61709 MTBF & 62443-4-2
The seven reliability factors we listed in March 2024 , hardware, programming, environment, power, data, installation, maintenance , are still the right checklist. The 2026 update is sharper: published
Detail
exists to prevent. This Engineering Note revisits every factor against current standards and 2026 flagship hardware , Allen-Bradley ControlLogix 5580, Siemens S7-1500 / S7-1200 G2, Mitsubishi iQ-R, Schneider M580 ePAC, Omron NX/NJ.
The seven 2024 reliability factors remain valid; each one now has a 2026 standard or measurement attached ,
in 2026 is published at the system level, rather than just the CPU , vendors quote MTBF figures that include chassis, power supply, and I/O.
certified components and patch-managed firmware are part of reliability engineering, not a separate IT concern.
Predictive maintenance , vibration, thermal, current signature , is a budgeted line item on a 2026 reliability roadmap, not a future nice-to-have.
Obsolete / EOL controllers are the single largest reliability risk in 2026: no firmware patches, no security updates, dwindling spare stock. Plan a migration path with KOEED before the part fails.
When this article was first published on 2024-03-07, the seven reliability factors read like field-tested advice. Two years later, five shifts have rewritten what each factor means in practice:
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