dead bus / synchro-check close permissive (graphical LD)¶


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

Authored for this suite, modeling a breaker close permissive gated by dead-bus or synchro-check

What is proved¶

From benchmarks/power_substation/g_dead_bus_close_check/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`	`!breaker_close \|\| !bus_live \|\| sync_check_ok`	A breaker may close onto a live bus only after synchro-check passes; closing onto a dead bus needs no check.

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	`1b4b53688a74`
`bomb.xml`	ladder program, PLCopen XML	3.0 KB	`7c1dd8485528`
`clean.xml`	ladder program, PLCopen XML	2.5 KB	`554438481289`
`props.yaml`	property file	0.3 KB	`de3b3aeaae7d`

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_dead_bus_close_check_bomb
VAR_INPUT
    close_request : BOOL;
    bus_live : BOOL;
    sync_check_ok : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    breaker_close : BOOL;
END_VAR


breaker_close := ((close_request AND NOT bus_live) OR (close_request AND sync_check_ok) OR (close_request AND maint));

END_PROGRAM

PROGRAM g_dead_bus_close_check_clean
VAR_INPUT
    close_request : BOOL;
    bus_live : BOOL;
    sync_check_ok : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    breaker_close : BOOL;
END_VAR


breaker_close := ((close_request AND NOT bus_live) OR (close_request AND sync_check_ok));

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_dead_bus_close_check__bomb (props.yaml, expected VIOLATION): v8.4 VIOLATION
g_dead_bus_close_check__clean (props.yaml, expected SAFE): v8.4 SAFE