SoftPLC

A software intermediary that decouples IEC 61131-3 control logic from the underlying physical hardware. This layer translates generic control instructions into hardware-specific calls, enabling the same application to execute across diverse industrial PCs, IPCs, and embedded systems without modification.

• Eliminates vendor lock-in by separating runtime from silicon
• Supports real-time Linux kernels and hypervisor-based partitioning
• Enables seamless migration between x86 and ARM64 architectures

A deterministic execution environment that compiles and runs the five standard PLC programming languages: Ladder Diagram, Structured Text, Function Block Diagram, Sequential Function Chart, and Instruction List. The runtime manages task scheduling, I/O scanning, and program execution within strict cycle time constraints.

• Supports multi-tasking with configurable priority and cycle times
• Provides online editing without stopping production processes
• Maintains backward compatibility with legacy PLC codebases

The ability to execute trained neural network models directly alongside deterministic control logic on the same industrial PC. This eliminates the latency and complexity of separate AI accelerator hardware by leveraging ONNX Runtime or TensorRT within the SoftPLC process space.

• Enables real-time quality inspection integrated with reject actuator control
• Supports predictive maintenance models that adjust machine parameters autonomously
• Uses shared memory for zero-copy data transfer between control and inference

A software-defined I/O abstraction that maps physical sensor and actuator signals to logical tags without hardwired addressing. SoftPLC platforms connect to distributed I/O modules over EtherCAT, PROFINET, and EtherNet/IP using standard network interface cards rather than proprietary backplanes.

• Supports hot-plugging of I/O modules during runtime
• Enables software-configurable signal conditioning and filtering
• Bridges legacy fieldbuses to modern OPC UA Pub/Sub architectures

Packaging the entire SoftPLC runtime, including its control application and AI models, as a lightweight container managed by orchestration platforms like K3s or Docker. This enables version-controlled, reproducible deployments across factory fleets with automated failover and scaling.

• Supports blue-green deployments for zero-downtime control updates
• Enables shadow mode validation of new logic against live production data
• Integrates with GitOps workflows for auditable change management

Guaranteed bounded latency for control loop execution through real-time operating system extensions like PREEMPT_RT or dedicated hypervisor cores. SoftPLC platforms achieve cycle times comparable to hardware PLCs while running on general-purpose compute, essential for motion control and high-speed packaging.

• Achieves sub-millisecond cycle times with proper kernel tuning
• Isolates control tasks on dedicated CPU cores via affinity masking
• Implements watchdog timers for fail-safe state transition on deadline miss

The deterministic software foundation upon which a SoftPLC executes. Unlike general-purpose operating systems, an RTOS guarantees that critical control tasks complete within strict, microsecond-level deadlines. This is non-negotiable for safety-critical loops where a missed cycle could mean a missed stop signal. Key characteristics include:

• Preemptive scheduling: High-priority control threads immediately interrupt lower-priority tasks.
• Minimal jitter: Consistent, predictable timing for I/O scans and logic solves.
• Priority inversion handling: Mechanisms to prevent a low-priority task from blocking a high-priority safety function.

A set of IEEE 802.1 Ethernet standards that bring deterministic, low-latency communication to standard network hardware. For a SoftPLC, TSN is the nervous system that ensures sensor data arrives and actuator commands are delivered on a guaranteed schedule, even when sharing bandwidth with video streams or best-effort traffic. Core components include:

• 802.1AS (Timing): Precise clock synchronization across all devices on the network.
• 802.1Qbv (Scheduling): A time-aware shaper that gates traffic queues based on a global schedule.
• 802.1CB (Redundancy): Seamless frame replication and elimination for ultra-reliable data delivery.

A discrete measure of risk reduction provided by a safety function, defined by standards like IEC 61508. When a SoftPLC is used in a safety-critical application, the entire software stack, from the RTOS to the application logic, must be certified to a target SIL level (e.g., SIL 3). This imposes rigorous constraints:

• Diagnostic Coverage (DC): The percentage of dangerous failures detected by built-in self-tests.
• Hardware Fault Tolerance (HFT): The ability to continue safe operation in the presence of one or more hardware faults.
• Software diversity: Using independently developed, dissimilar code paths to protect against systematic errors.

A hardware-isolated, trusted execution environment within the processor that protects sensitive code and data from the host OS. For a SoftPLC, this is critical for safeguarding proprietary control algorithms and cryptographic keys. Even if the general-purpose OS is compromised, the logic executing inside the enclave remains confidential and unmodified. Key capabilities:

• Memory encryption: Transparently encrypts enclave memory regions in DRAM.
• Remote attestation: Cryptographically proves to a remote manager that the correct, untampered SoftPLC runtime is executing.
• Sealing: Binds data to a specific enclave identity, ensuring it can only be decrypted on that exact device.