Chapter 28 — Field practice | Technologist OT, IoT and cyber-physical security

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Chapter 28 — Field practice

Lesson map

Lesson 28 published. Map, example, EX082.

flowchart TD
  N0["Learning outcomes"]
  N1["28.1 Site safety first"]
  N2["28.2 Permits and lock-out"]
  N3["28.3 Communication"]
  N4["28.4 Reflection"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5
  N5 --> EX["Worked example"]
  EX --> Q["Exercise EX082"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["28.1 Site safety first"]
  N2["28.2 Permits and lock-out"]
  N3["28.3 Communication"]
  N4["28.4 Reflection"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX082"]

[Learning outcomes]
    |
    v
[28.1 Site safety first]
    |
    v
[28.2 Permits and lock-out]
    |
    v
[28.3 Communication]
    |
    v
[28.4 Reflection]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX082]

Learning outcomes

You will (1) work safely on an industrial site under supervision; (2) follow site rules for permits, PPE and lock-out; (3) communicate with operators, contractors and managers; and (4) reflect on field experience.

28.1 Site safety first

An ammonia refrigeration plant has hazards a computing student may not expect: toxic gas, moving machinery, cold rooms where exposure is limited, forklifts on the dock. Before any visit: site induction, required PPE, knowledge of alarm signals and muster points, and an escort. Never enter the machine room without the refrigeration engineer's permission.

Priya's visits always start at the gatehouse induction, and she enters the machine room only with the contractor or refrigeration engineer.

The induction covers ammonia alarms and muster points, which apply to her as to anyone.

28.2 Permits and lock-out

Work on panels may require a permit-to-work and, for electrical isolation, lock-out/tag-out by qualified staff. A technologist reading a front-panel display may need an escort; touching anything inside a live panel is not part of the role.

At NCS, Priya read PLC-R2's version from its front-panel display with the contractor beside her; that is observation, not work on the panel. The MP-2 cellular router was photographed, not unplugged: removing it was the facilities manager's decision, made after the contractor confirmed what it was for.

28.3 Communication

Operators know the plant; listen first. Explain what you will do, how long it takes and how it could affect them. Before leaving, tell the shift lead what you did and what you found that matters to them today.

On her third visit, when an operator asked her to reset a frozen HMI, Priya explained why she would not and what she could do instead: check the switch port counters, which was permitted read-only, and call the contractor. Before leaving, she told the shift lead the cause, a failing power supply, and that no security issue had been found.

28.4 Reflection

After each visit, write: what I did, what I observed, what I would do differently, and any safety or ethical question. Reflection is assessed in this chapter because it is how field judgement grows.

Priya's entry for her third visit might read: did, checked switch port counters for a frozen HMI and called the contractor; observed, a failing power supply as the cause, confirmed by the contractor; differently, ask on arrival who handles HMI faults on that shift; ethical question, the operator's request that she reset the HMI as "the IT person", which she declined because a reset could destroy evidence and was not her task under the site procedure. Assessors look for the last line most.

Worked example (synthetic NCS)

On Priya's third visit an operator asks her to "quickly reset" a frozen HMI because she is "the IT person". She declines: HMI resets are the operator's or contractor's task under the site procedure, and a reset might destroy evidence if the freeze has a cyber cause. She helps by checking the switch port counters (permitted read-only) and calls the contractor, who finds a failing power supply.

Synthetic case — Northgate Cold Storage. The visit is invented.

Errors and limits

Field placements vary; follow the host's rules even where they differ from this book. Reflection notes must not include customer data or credentials.

Exercises

EX082 — Pre-visit checklist. List four things to have before entering NCS's machine room. Rubric: 3 = induction, PPE, escort/permission, alarm/muster knowledge; 2 = three; 1 = laptop; 0 = none.
EX083 — Declining the reset politely. Write what Priya says to the operator. Rubric: 3 = declines, explains role and evidence reason, offers help, calls right person; 2 = partial; 1 = refuses curtly; 0 = resets.
EX084 — A reflection entry. Write the "what I would do differently" line for that visit. Rubric: 3 = specific, actionable improvement; 2 = vague; 1 = minimal attempt; 0 = none.

Synthesis

Field practice builds the habits that keep people safe and keep the plant trusting security staff: preparation, staying in role, clear communication and reflection.

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