PLC CPU and Memory in 2026: ARM Cortex, MRAM, ECC | KOEED
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PLC CPU and Memory in 2026: ARM Cortex, MRAM, ECC | KOEED
Two years after our 2024 primer, the heart of every modern PLC has changed. ARM Cortex multicore SoCs, on-chip ECC, MRAM retain storage, and secure boot are now baseline on every major platform. This 2026 update walks through what changed, what to specify in your next BOM, and which
Detail
Modern PLC CPUs are now ARM Cortex-A/M multicore SoCs with on-chip ECC and hardware-assisted motion control.
Retain memory has shifted from battery-backed SRAM to MRAM and supercap-buffered DDR4 with wear-leveling.
Program and asset storage is moving to encrypted, secure-boot NOR/NAND with OPC UA PKI integration.
Legacy architectures (microprocessor / microcontroller / PGA / ASIC) still ship in mid- and low-end controllers and remain relevant for service and migration.
Sourcing the right replacement starts with part number, firmware revision, and retain-memory type , send the BOM to
Today’s PLCs pair ARM Cortex multicore CPUs with ECC-protected DDR, MRAM or supercap-buffered retain, and encrypted secure-boot flash. Knowing each subsystem helps engineers pick the right module for new builds and source clean replacements for legacy racks.
The original 2024 article framed CPUs in four families: microprocessor, microcontroller, FPGA/PGA, and ASIC. That taxonomy is still valid for understanding inventory, but in 2026 the silicon has moved on. A 2024-era S7-1500 CPU, a ControlLogix 1756-L7x, or a Mitsubishi iQ-R CPU was already an ARM Cortex-A9 / A15 single-core. A current ControlLogix 1756-L8x, a SIMATIC S7-1500 G2, or a MELSEC iQ-R n-CPU now ships as a Cortex-A53 / A72 multicore SoC with dedicated motion coprocessors, hardware-accelerated OPC UA Pub/Sub, and on-chip ECC. In other words, the difference between a 2024 PLC and a 2026 PLC is the same magnitude as the difference between a 2014 PLC and a 2024 one.
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