System

Remote Weapon Station (RWS), {{entity:se-remote-weapon-station-rws}}. Decomposition phase, final session: two remaining pending subsystems — {{entity:Communications Interface Unit}} (SIL 0) and {{entity:Power Distribution Unit}} (SIL 0) — were decomposed this session, bringing the spec tree to 8/8 complete. The project now holds 145 requirements across 6 documents and 107+ trace links.

Decomposition

Communications Interface Unit ({{hex:50F57258}} TDP, {{hex:D4F57018}} VCNI, {{hex:50E57008}} CPG, {{hex:C6851058}} EMC):

The CIU separates external data link functions from the safety-rated FCS, a decision documented in {{sub:ARC-REQ-004}}. It decomposes into four components. The {{entity:Tactical Data Link Processor}} handles MIL-STD-6016 (STANAG 5516) message encoding/decoding for BMS integration. The {{entity:Video Compression and Network Interface Module}} provides H.264/H.265 compression and RTP streaming at 15fps per {{sub:SUB-REQ-035}}. The {{entity:CAN Bus and Serial Protocol Gateway}} bridges the ISO 11898 vehicle CAN bus to internal Ethernet and distributes GPS NMEA-0183 data at 10Hz per {{sub:SUB-REQ-036}}. The {{entity:EMC Filter and Surge Protection Assembly}} provides MIL-STD-461G CE101/CE102 and IEC 61000-4-2 Level 4 ESD protection at the CIU boundary per {{sub:SUB-REQ-037}}.

flowchart TB
  EMC["component<br>EMC Filter and Surge Arrester"]
  TDP["component<br>Tactical Data Link Processor"]
  VCNI["component<br>Video Compression and NI Module"]
  CPG["component<br>CAN Bus and Serial Protocol Gateway"]
  EMC --> TDP
  EMC --> VCNI
  EMC --> CPG
  VCNI -->|GigE metadata| TDP
  CPG -->|GPS UDP 10Hz| TDP
  TDP -->|MIL-STD-6016| BMS["external<br>Battle Management System"]

Power Distribution Unit ({{hex:C6853058}} PIFC, {{hex:D6D51018}} DCDC, {{hex:D6B53018}} PDPM, {{hex:D5F77018}} PMCU):

The PDU separates passive filtering ({{entity:Primary Power Input Filter and Surge Arrester}}) from active switching ({{entity:Power Distribution and Protection Module}}) and secondary rail conversion ({{entity:DC-DC Converter Array}}) to allow LRU-level replacement per SYS-REQ-015. The {{entity:Power Monitor and Control Unit}} runs a supervisory control loop reporting 10Hz power telemetry to the Fire Control Computer per {{sub:SUB-REQ-041}}. A critical interface requirement {{ifc:IFC-REQ-028}} mandates an always-on, non-load-shedded 28VDC branch to the Safety Interlock System — load faults on any other branch cannot interrupt the SIS supply, ensuring the SIL 3 safety function remains available through all PDU fault scenarios.

flowchart TB
  PIFC["component<br>Primary Power Input Filter"]
  DCDC["component<br>DC-DC Converter Array"]
  PDPM["component<br>Power Distribution and Protection Module"]
  PMCU["component<br>Power Monitor and Control Unit"]
  VEH["external<br>Vehicle 28VDC"]
  VEH --> PIFC
  PIFC --> DCDC
  PIFC --> PDPM
  PDPM -->|always-on SIS rail| SIS["subsystem<br>Safety Interlock System"]
  PDPM -->|switched loads| FCS["subsystem<br>FCS/TDA/EOSA/OCU/CIU"]
  PMCU -->|RS-422 telemetry| FCC["subsystem<br>Fire Control Computer"]

Analysis

{{trait:Powered}} classification on the Dual-Channel Safety Controller and Hardware Firing Interlock Relay produced two high-severity lint findings; both were acknowledged in session 619. The IFC-REQ-028 always-on SIS supply requirement directly addresses the architectural concern those findings surfaced — the PDU decomposition provides the missing engineering artifact.

The CAN Bus and Serial Protocol Gateway has a {{trait:System-integrated}} and {{trait:Processes Signals/Logic}} profile ({{hex:50E57008}}) consistent with industrial protocol gateway architectures. Cross-domain analogs in the Factory corpus (autonomous vehicle CAN-to-Ethernet gateways) confirm the 5ms latency budget is achievable with standard embedded bridge hardware.

The two homeless VER entries (REQ-SEREMOTEWEAPONSTATIONRWS-001/002) resulted from specifying --document verification-plan (incorrect slug — should be verification-requirements). Proper VER-REQ-023 and VER-REQ-024 were created. The homeless entries reside structurally in section-1774572686361 but their document reference is null; they were not deleteable via CLI and will require QC session cleanup.

Requirements

{{sub:SUB-REQ-034}}–{{sub:SUB-REQ-041}}: 8 subsystem requirements across CIU and PDU. {{ifc:IFC-REQ-025}}–{{ifc:IFC-REQ-029}}: 5 interface requirements. VER-REQ-023–VER-REQ-026: 4 verification entries. All have rationale and verification methods. Trace links created from SYS-REQ-012, SYS-REQ-013, SYS-REQ-016, SYS-REQ-017. The SIS always-on supply chain (SYS-REQ-009 → IFC-REQ-028 → VER-REQ-025) is the most safety-significant new trace chain established this session.

Next

Spec tree is 8/8 complete. The 26 orphan requirements (primarily ARC entries and several IFC/SUB from prior sessions) and the 2 homeless VER entries warrant a QC pass. High-severity lint findings are acknowledged; medium findings are pervasive but expected for a system of this complexity. Quality Engineer flow should run next to address orphan trace coverage and close the fetchErrors metric.