Overview¶

The taktora workspace builds a soft-real-time runtime stack on iceoryx2, in two layered pieces:

taktora-executor turns IPC events, intervals, and request/response activity into deterministic, observable schedules of executable items.
taktora-connector-* exposes typed channels behind a uniform plugin surface, so application logic talks to EtherCAT, Zenoh, and any future fieldbus through the same ChannelReader / ChannelWriter types.

System context¶

The diagram below maps the full taktora workspace at a glance; see Soft-RT PLC runtime heart (PLC runtime heart on iceoryx2 (FEAT_0010)), Connector framework (Connector framework (FEAT_0030)), Connector framework — architecture (arc42), and Motion — trajectory core architecture for detailed breakdowns of each layer.

        %%{init: {"flowchart": {"rankSpacing": 60, "nodeSpacing": 40}}}%%
flowchart TB

  subgraph BUILD["Build-time codegen (not present at runtime)"]
    direction LR
    ESI["ESI device-codegen\n(FEAT_0050)\nethercat-esi → typed driver structs"]
    CAN_CG["CANopen codegen\n(FEAT_0060)\nEDS → typed driver structs"]
    NETCFG["ethercat-netcfg\n(FEAT_0080)\nnetwork.yaml → &'static bus tables"]
  end

  subgraph RUNTIME["taktora runtime"]
    direction TB
    IOX[("iceoryx2\nzero-copy IPC")]
    EXEC["taktora-executor\ncyclic · event · req-resp dispatch\nof ExecutableItems"]
    IOX <--> EXEC

    subgraph CONN["taktora-connector-* plugin surface\n(ChannelReader / ChannelWriter)"]
      direction LR
      EC["connector-ethercat"]
      ZN["connector-zenoh"]
      CN["connector-can\n(SocketCAN)"]
      MQ["connector-mqtt"]
    end

    EXEC <--> CONN

    MOTION["taktora-motion-core\n(no_std, alloc-free)\nCSP setpoint generation"]
    MOTION -->|"commanded position"| EC
  end

  subgraph INFRA["Cross-cutting workspace infrastructure"]
    direction LR
    ALLOC["taktora-bounded-alloc\n#[global_allocator]\n(FEAT_0040)"]
    LOG["taktora-log + taktora-log-dlt\nlogging facade · DLT backend\n(FEAT_0070)"]
  end

  APP["Application logic\nExecutableItems"]
  APP <--> EXEC

  subgraph EXT["External systems"]
    direction TB
    EBUS["EtherCAT bus\n+ CiA 402 drives (CSP)"]
    ZNET["Zenoh network"]
    CBUS["CAN bus"]
    MQTT["MQTT broker"]
  end

  EC -->|"PDO process data"| EBUS
  ZN <--> ZNET
  CN <--> CBUS
  MQ <--> MQTT

  ESI -.->|"&'static driver tables"| EC
  CAN_CG -.->|"&'static driver tables"| CN
  NETCFG -.->|"&'static bus tables"| EC

  INFRA -.->|"workspace-wide"| RUNTIME

This specification frames the workspace as the runtime heart of a soft-real-time PLC: a foundation for non-safety industrial automation, robotics control loops, machine-monitoring runtimes, and R&D testbeds where occasional jitter is acceptable. The framing follows directly from a gap analysis (recorded in Soft-RT PLC runtime heart) that distinguishes the capabilities taktora already provides from those that must be added before it can credibly call itself a soft-RT PLC.

What is out of scope for the runtime heart:

Hard-real-time guarantees (cycle deadlines bounded to microsecond jitter under any load).
IEC 61508 / 26262 functional safety certification or SIL / ASIL claims.
IEC 61131-3 frontends (ladder logic, function block diagram, structured text).
Hot-standby, redundancy, online change.
Specific fieldbus protocols (EtherCAT, Modbus, Profinet, CIP); only the integration interface is in scope.

This document is structured as engineering artefacts. Top-level capabilities are feat directives; individual obligations are req directives that :satisfies: their parent feature. Every artefact carries a stable ID (FEAT_NNNN, REQ_NNNN) and a lifecycle :status:.

Reading order¶

Start with Soft-RT PLC runtime heart for the full feature/requirement decomposition. Work-in-progress sections — Architecture and Verification — will land alongside the implementation work that closes the gap requirements.

Status legend¶

open — drafted; not yet reviewed.
draft — under active authoring (used during edits).
reviewed — passed at least one structured review.
approved — accepted into the baseline.

All artefacts in this initial drop are authored at open until they are reviewed; the status lifecycle is honest about provenance rather than optimistic.