4. Scenarios, Objectives and Scoring

A scenario is a saved exercise: where the plant starts, how fast the clock runs, which faults come in and when, and what the trainee has to achieve to pass. Scenarios live inside the flowsheet file, so the same exercise can be run by any instructor with the file.

What you will learn

• Creating a scenario with scheduled malfunctions
• The four kinds of objective and how each is scored
• Loading and running a scenario, ending the exercise, reading the report

Prerequisites

• Page 3: you have injected a fault by hand

The Scenarios tab

The list on the left holds the scenarios in the file. New adds one, Delete removes the selected one, Save all writes them to the flowsheet (remember to save the file afterwards), Load makes the selected scenario the active one.

Fields of a scenario:

Field	Meaning
Name, Description	What the trainee is told, and what you tell yourself
Schedule	The dynamics schedule to run
Initial state	The stored flowsheet state to restore when the exercise starts (page 2 snapshots appear here)
Speed (x)	The speed factor the exercise starts with
Scheduled malfunctions	Rows of Malfunction, Target, Severity (0-1), Ramp (s), At (s): the fault fires automatically At that many simulated seconds after Start
Objectives and scoring	Rows described below

Objectives

Each objective has a Kind, a Condition (the same building block the interlocks use: a Target tag, a Property, an operator and a value, or an alarm level), Points for passing and, for two of the kinds, a Penalty. Deadlines and hold times are simulated seconds after Start; values are in the flowsheet's display units.

Kind	Passes when	Scoring
Reach	The condition becomes true before Deadline s and stays true for Hold s	Full points on success; zero if the deadline passes
Avoid	The condition never becomes true	Each occurrence costs Penalty points; with a penalty of zero, one occurrence fails the objective
KeepInRange	The property stays between Min and Max for at least the required fraction of the exercise (90 % by default)	Each second outside the range costs Penalty; the fraction decides pass or fail
OperatorAction	The trainee does something whose journal text contains Action text, before the deadline	Full points on success

The Condition column also accepts Alarm active with a level (LL, L, H, HH) on a gauge, and Interlock tripped with an interlock name, which makes objectives such as "never let PIT-001 reach HH" or "do not trip the SIS" one row each.

Build the first exercise

Scenario Feed valve fails open:

• Initial state a, schedule schedule1, speed 5
• Scheduled malfunction: ValveFailOpen on FV-001, severity 1, ramp 20, at 60
• Objectives:

Name	Kind	Condition	Deadline	Hold	Points	Penalty
Hold the pressure	KeepInRange	PIT-001 / Monitored Value, Min 150, Max 400			30	0.1 per s
No HH pressure	Avoid	Alarm active HH on PIT-001			20	0
Take PID-012 to manual	OperatorAction	Action text PID-012 mode -> MANUAL	240		10
Pressure back to 2 bar	Reach	PIT-001 / Monitored Value < 250	600	30	20

Press Save all, then save the flowsheet.

Action text

The text an objective looks for is the text the journal records. Do one action on the operator panel, read its line in the Journal tab, and copy the part that identifies it. PID-012 set point matches any set point change on that controller; LV-001 opening matches any manual opening.

Run it

1. Select the scenario and press Load. The initial state is restored, the faults are armed, the objectives reset; the journal says so.
2. Start. At 60 s the feed valve begins to open; the trainee (you, for now, through the operator panel of page 5) has to keep the separator inside limits.
3. The Exercise tab shows every objective with its status (Pending, Passed, Failed), points so far and a detail column ("outside for 42 s", "met at 00:03:10").
4. End exercise and score freezes the session and decides pending objectives on what happened so far: a Reach that has not happened fails, an Avoid that never fired passes. Penalties never take an objective below zero.
5. Report... opens the exercise report, a Markdown document with the score, each objective's result, counts (operator actions, alarms raised, interlock trips, faults injected, failed steps) and the full timeline. Save it as .md and hand it to the trainee.

Designing good scenarios

• One fault per scenario at first. Combine faults only after the trainee handles each alone.
• Give the trainee a quiet minute before the first fault: the At column exists for that.
• Use ramps. A step change is a puzzle; a ramp is a plant.
• Score what matters: an Avoid on the HH alarm, a KeepInRange on the product spec, an OperatorAction for the procedure step you are teaching.
• Keep the deadline generous the first time and tighten it in the next scenario.

The next page moves to the trainee's side of the room.