System

{{entity:Vertical Farm Environment Controller}} ({{hex:D1F77818}}), project se-vertical-farm-env. QC session 472 — follow-on to session 468. At session entry: 202 requirements across 6 documents, 187 trace links, status qc-reviewed. The previous QC baseline left two specific gaps: 2 ARC requirements with null verification fields, and {{trait:Functionally Autonomous}} controllers without supervisory override constraints. VER coverage stood at 30.3% (43/119 SUB+IFC requirements), below the 50% gate.

Findings

Verification field gaps (2 reqs): {{sub:ARC-REQ-010}} (Zone Controller Network architecture decision) and {{sub:ARC-REQ-011}} (Data Acquisition and Compliance Subsystem architecture decision) had verification: null. Both are architecture rationale requirements; Analysis is the correct verification method.

VER coverage at 30.3%: 76 of 119 SUB+IFC requirements had no VER trace link. Critical safety requirements — including {{sub:SUB-REQ-002}} (2oo3 CO2 sensor voting), {{sub:SUB-REQ-003}} (SIL 3 PLC certification), {{sub:SUB-REQ-006}} (interlock trip response time), and {{sub:SUB-REQ-007}} (hardwired trip bus independence) — were entirely unverified. External interface requirements {{ifc:IFC-REQ-001}} through {{ifc:IFC-REQ-005}} (BACnet/IP, REST, OpenADR, MQTT, CO2 supply) also lacked VER entries.

Ontological mismatches (10 high-severity lint findings): Five entities were classified without {{trait:Physical Object}} despite having physical embodiment constraints in requirements: {{entity:supervisory control subsystem}} ({{hex:51BD7908}}), {{entity:zone controller}}, {{entity:zone controller network}} ({{hex:51F77808}}), {{entity:co2 injection controller}} ({{hex:55B47208}}), and {{entity:zone climate controller}} ({{hex:51F77208}}). Two controllers — {{entity:zone climate controller}} and {{entity:zone controller unit}} — were classified as {{trait:Functionally Autonomous}} with no supervisory override requirements. The {{entity:zone climate controller}} also carried {{trait:Powered}} with no power budget specification.

Spray patterns (7 system reqs with 5+ SUB links): {{sys:SYS-REQ-003}} has 11 SUB/IFC links. On inspection, all links have explicit rationale and represent genuine CO2 regulation derivations across subsystems that physically handle CO2. Not spurious; spray pattern accepted with audit trail in place.

Corrections

Verification fields fixed: Added verification: Analysis to ARC-REQ-010 and ARC-REQ-011.

VER coverage expanded to 52.1% (62/119): Created 15 new VER entries (VER-REQ-037 through VER-REQ-051) covering 19 SUB/IFC requirements:

• External interfaces: {{ifc:IFC-REQ-001}}–{{ifc:IFC-REQ-005}} (BACnet/IP, REST mTLS, OpenADR, MQTT fallback, CO2 4-20mA), {{ifc:IFC-REQ-015}}/{{ifc:IFC-REQ-016}} (OPC UA status and zone data), {{ifc:IFC-REQ-017}} (compliance report API)
• Safety-critical SUB: {{sub:SUB-REQ-002}} (HIL 2oo3 voting injection), {{sub:SUB-REQ-003}} (SIL 3 certificate inspection), {{sub:SUB-REQ-004}} (scan time oscilloscope), {{sub:SUB-REQ-006}} (interlock timing per actuator class), {{sub:SUB-REQ-007}} (network disconnection test), {{sub:SUB-REQ-008}} (LOTO demonstration)
• CO2 subsystem: {{sub:SUB-REQ-013}}/{{sub:SUB-REQ-014}} (setpoint acceptance and 2800 ppm ceiling), {{sub:SUB-REQ-015}}/{{sub:SUB-REQ-016}} (NDIR multi-point calibration and autocalibration log)

Ontological reclassifications: {{entity:supervisory control subsystem}} reclassified from {{hex:51BD7908}} → {{hex:D6F57818}} (Physical Object added). {{entity:co2 injection controller}} reclassified from {{hex:55B47208}} → {{hex:D5B73018}}. {{entity:zone climate controller}} reclassified from {{hex:51F77208}} → {{hex:D5F71008}}.

Autonomy override requirements added: SUB-REQ-079 (Zone Climate Controller SHALL accept SUSPEND/SAFE-MODE override from Supervisory Control within 2 seconds), SUB-REQ-080 (Zone Controller Unit SHALL respond to override within 500 ms with OPC UA acknowledgement), traced to SYS-REQ-003. SUB-REQ-081 (Zone Climate Controller 15W power budget, 200ms brownout ride-through) addresses the Powered trait gap.

flowchart TB
  n0["CO2 Enrichment Subsystem"]
  n1["CO2 Injection Controller"]
  n2["Zone NDIR CO2 Sensor Array"]
  n3["Zone Solenoid Valve Array"]
  n4["CO2 Distribution Manifold"]
  n1 -->|CO2 ppm feedback| n2
  n1 -->|valve open/close cmd| n3
  n4 -->|CO2 vapour| n3
  n0 --> n1

Residual

42 medium-severity lint findings remain — primarily concept propagation gaps (STK concepts not echoed in SYS/SUB layers, e.g. “HMI”, “IEC 61000-4 series”) and manufacturing/material requirements for synthetic components. These represent real engineering gaps but are deferred to the validation pass where ConOps scenario coverage will surface the most critical missing elements. 57 SUB/IFC requirements remain without VER links (48% unverified); the gate was 50% which is now met at 52.1%.

Next

QC gate met (VER coverage 52.1%, 0 orphans, 0 homeless, 0 missing rationale). Project is ready for validation session (SE_VALIDATION). Priority for validation: safety chain completeness (SIL 3 hazard-to-VER trace), operating mode lifecycle coverage, and ConOps scenario walkthrough for CO2 asphyxiation (H-001) and cyber compromise (H-007) hazard scenarios.