Trace machine, sensor, and maintenance-event context

Question for this chapter

What machine context should accompany CNC-03's alert in the maintenance handoff?

Why this matters now

If you hand over only one alert row, the crew must rediscover which sensors belong to the machine and whether a maintenance event exists. The ontology connects those parts of the same incident.

Try it

Run the ontology_materialization pipeline under processed. Confirm the resulting row counts.

In Graph Explorer, inspect CNC-01's complete sensor configuration first.

MATCH path=(s:iot_sensor)-[:iot_reads_from]->(m:iot_machine)
WHERE m.machine_id = 'CNC-01'
RETURN path

CNC-01 connects to vibration, temperature, and pressure sensors, but it has no current HIGH event. Sensor count and risk are different concepts.

Now inspect the first target, CNC-03.

MATCH path=(m:iot_machine)-[:iot_triggers]->(e:iot_maintenance_event)
WHERE m.machine_id = 'CNC-03'
RETURN path

The result should connect CNC-03 to the maintenance event created by its HIGH vibration alert.

flowchart LR
    accTitle: Separate sensor configuration from maintenance incidents
    accDescr: CNC-01 connects to three sensors but no current incident, while CNC-03 connects from its vibration sensor to a HIGH maintenance event.
    s1["Three CNC-01 sensors"] --> m1["CNC-01"]
    s3["CNC-03 vibration sensor"] --> m3["CNC-03"]
    m3 --> e3["HIGH maintenance event"]

Interpret the result

The first query answers machine configuration; the second answers current incident. More sensors do not make CNC-01 a higher priority. CNC-03 has only two sensor types, but its vibration alert and maintenance event provide the context the crew needs.

Next decision

You have the source signal, statistical check, health score, and relationship context. In the next chapter, review the four core decisions briefly. Then explain why all three machines remain in scope while CNC-03 goes first.