BAS-502 Visual Aid Library
Figure-use rule
Each figure is an orientation and reasoning aid, not a project drawing. Learners must pair it with the current sequence, point list, wiring/piping documents, manufacturer instructions, and as-found evidence.
Normal-rule anchor
Speed begins with a trustworthy baseline; unknown dependencies, unsupported combinations, or unproved recovery are stop conditions.
Case overlay
A supervisor sees three stations but one has different modules, another has wrong time, and no one can identify the last known-good backup.
Calculation/evidence callout: Reconcile versions, capacity/headroom, clock offset, backup age, certificate expiry, issue counts, and proposed change blast radius.
Normal-rule anchor
A working insecure connection is a critical defect; trust, identity, authorization, availability, and emergency access must all be engineered and tested.
Case overlay
A certificate replacement breaks one peer, an old service account remains active, and a shared admin credential appears in a handoff note.
Calculation/evidence callout: Calculate renewal lead, role coverage, privilege exceptions, session/revocation time, certificate chain dates, and permitted service paths.
Normal-rule anchor
An alarm exists only when the right condition reaches the right responsible person with context, timing, action, audit, and verified return-to-normal behavior.
Case overlay
A single communication loss creates 800 alarms, while the actual root event is buried and after-hours routing is inactive.
Calculation/evidence callout: Calculate event rate, peak flood, persistence/deadband, delivery latency, nuisance percentage, and residual coverage after proposed rationalization.
Normal-rule anchor
A query result is evidence only after scope, type, time, quality, units, expected count, representative validation, and known gaps are documented.
Case overlay
A fleet energy report mixes units, hides stale values, and loses short cycling because intervals differ by station.
Calculation/evidence callout: Calculate sampling adequacy, storage and retention, gap percentage, time offset, rollup error, and report reconciliation.
Normal-rule anchor
Query before clicking, but never treat the result set as authorized targets until representative validation, exclusions, owners, pilot, and rollback are complete.
Case overlay
A BQL query returns 460 points for a batch extension change, including 14 wrong types and six customer-specific exceptions.
Calculation/evidence callout: Compare expected/actual counts, sample confidence, false-positive/negative rate, target coverage, exception count, and reconciliation after pilot.
Normal-rule anchor
Tags are governed data, not labels; vocabulary, relationships, scope, source, validation, version, and change ownership determine meaning.
Case overlay
Two campuses use the same tag spelling differently and a query silently omits VAVs with an older template.
Calculation/evidence callout: Calculate required/actual tag coverage, orphan and collision counts, query precision/recall, exception rate, and migration completeness.
Normal-rule anchor
Reuse is safe only when its interface contract and state matrix are explicit and regression-tested on representative variants.
Case overlay
A fleet VAV template works on ten boxes but writes to the wrong priority on two older controllers and hides stale airflow.
Calculation/evidence callout: Measure binding/interface coverage, variant pass rate, task steps/errors, state coverage, and changed-case regression results.
Normal-rule anchor
A batch operation combines target selection, authorization, timing, resource impact, write semantics, process consequence, exceptions, and restoration; success count alone is insufficient.
Case overlay
A tuning-policy change reduces traffic but causes startup output blips on legacy controllers after a power event.
Calculation/evidence callout: Calculate target count, job duration, poll/write load, queue growth, exception rate, response latency, and before/after resource margin.
Normal-rule anchor
Read the complete exception chain and correlate time, component, service, resource, physical symptom, and changed case before concluding cause.
Case overlay
A station becomes slow after a graphics release; output shows repeated binding exceptions, a full history queue, and intermittent driver timeouts.
Calculation/evidence callout: Calculate event rate, resource trend, queue growth, error concentration, response latency, and whether timing supports the proposed causal chain.
Normal-rule anchor
The professional result is a reproducible evidence package: what changed, why, where, under whose authority, what was tested, what failed, how recovery was proved, and what remains open.
Case overlay
A fleet optimization passes initial checks, then one station fails after reboot and another retains a temporary command.
Calculation/evidence callout: Reconcile planned/applied/failed/rolled-back targets, checksum and version state, RPO/RTO, functional pass rate, temporary-state count, and open risk ownership.