transformer protect interlock (graphical LD)¶


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

Authored for this suite to cover this domain with genuine control logic

What is proved¶

From benchmarks/power_substation/g_transformer_protect/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`	`!(transformer_on && oil_temp_high)`	The transformer must never be energised while oil temperature is high.

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	1.0 KB	`ecb62836be05`
`bomb.xml`	ladder program, PLCopen XML	3.2 KB	`7a3e194e072d`
`clean.xml`	ladder program, PLCopen XML	2.7 KB	`9a5889d29e2a`
`props.yaml`	property file	0.2 KB	`93c3ea4c40ff`

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_transformer_protect_bomb
VAR_INPUT
    energize_cmd : BOOL;
    oil_temp_high : BOOL;
    lockout : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    transformer_on : BOOL;
    trip : BOOL;
END_VAR


transformer_on := (((NOT oil_temp_high OR (oil_temp_high AND maint)) AND energize_cmd) AND NOT lockout);
trip := oil_temp_high;

END_PROGRAM

PROGRAM g_transformer_protect_clean
VAR_INPUT
    energize_cmd : BOOL;
    oil_temp_high : BOOL;
    lockout : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    transformer_on : BOOL;
    trip : BOOL;
END_VAR


transformer_on := ((NOT oil_temp_high AND energize_cmd) AND NOT lockout);
trip := oil_temp_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_transformer_protect__bomb (props.yaml, expected VIOLATION): v8.4 VIOLATION
g_transformer_protect__bomb__viac via C (props.yaml, expected VIOLATION): master VIOLATION
g_transformer_protect__clean (props.yaml, expected SAFE): v8.4 SAFE
g_transformer_protect__clean__viac via C (props.yaml, expected SAFE): master SAFE