independent high-pressure trip (graphical LD)¶


suite id	`g_independent_hp_trip`
domain	chemical_batch
language	LD-graphical
difficulty	medium
validation status	validated
origin	authored
license	CC-BY-4.0

Authored for this suite, modeling a single independent overpressure trip layer distinct from the existing 2-of-3 voted trip

What is proved¶

From benchmarks/chemical_batch/g_independent_hp_trip/props.yaml. What each kind claims, and what it becomes on either route, is on The properties we prove.

id	kind	claim	requirement
`P1`	`invariant`	`!pressure_high \|\| vent_valve`	The independent high-pressure trip must vent whenever pressure is high, regardless of what the batch sequencer is doing.

Variants¶

file	expected verdict	violates	method
`clean.xml`	SAFE	none	expert
`bomb.xml`	VIOLATION	`P1`	fault-injection

Files¶

file	what it is	size	sha256
`benchmark.yml`	benchmark metadata	1.1 KB	`1e73b0ef5cb5`
`bomb.xml`	ladder program, PLCopen XML	2.5 KB	`f1efeeda1cb1`
`clean.xml`	ladder program, PLCopen XML	1.8 KB	`067497f30cc1`
`props.yaml`	property file	0.2 KB	`272e188ff6a7`

Structured text, derived¶

Read off the ladder graph by runner/ld_to_st.py: every rung's contacts and coils rewritten as IEC 61131-3 assignments, in the same series/parallel logic the PLCopen XML encodes. This is a reading aid, not a second source of expected verdicts; ESBMC verifies the ladder program shown above, never this rendering.

bomb.xmlclean.xml

PROGRAM g_independent_hp_trip_bomb
VAR_INPUT
    pressure_high : BOOL;
    sequence_step_active : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    vent_valve : BOOL;
END_VAR


vent_valve := ((pressure_high AND NOT maint) OR (pressure_high AND sequence_step_active));

END_PROGRAM

PROGRAM g_independent_hp_trip_clean
VAR_INPUT
    pressure_high : BOOL;
    sequence_step_active : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    vent_valve : BOOL;
END_VAR


vent_valve := pressure_high;

END_PROGRAM

Recorded runs¶

A task can carry two routes. ld is ESBMC's ladder front end reading the program directly. via C is the same solver reached through Beremiz and MatIEC, which is the only route that reaches ST, IL, FBD and SFC; see How ESBMC-PLC works.

g_independent_hp_trip__bomb (props.yaml, expected VIOLATION): v8.4 VIOLATION
g_independent_hp_trip__clean (props.yaml, expected SAFE): v8.4 SAFE