elevator door interlock (graphical LD)¶


suite id	`g_elevator_door`
domain	elevator
language	LD-graphical
difficulty	easy
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/elevator/g_elevator_door/props.yaml. What each kind claims, and what it becomes on either route, is on The properties we prove.

id	kind	claim	requirement
`P1`	`mutual_exclusion`	never true together: `door_open`, `drive`	The door must never be open while the car is driving.

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	`a8647f5eca65`
`bomb.xml`	ladder program, PLCopen XML	3.2 KB	`3a7c07acb28c`
`clean.xml`	ladder program, PLCopen XML	2.7 KB	`c106fb097ac9`
`props.yaml`	property file	0.2 KB	`99cf55c29e79`

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_elevator_door_bomb
VAR_INPUT
    open_req : BOOL;
    move_req : BOOL;
    at_floor : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    door_open : BOOL;
    drive : BOOL;
END_VAR


door_open := (((NOT move_req OR (move_req AND maint)) AND open_req) AND at_floor);
drive := move_req;

END_PROGRAM

PROGRAM g_elevator_door_clean
VAR_INPUT
    open_req : BOOL;
    move_req : BOOL;
    at_floor : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    door_open : BOOL;
    drive : BOOL;
END_VAR


door_open := ((NOT move_req AND open_req) AND at_floor);
drive := move_req;

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_elevator_door__bomb (props.yaml, expected VIOLATION): v8.4 VIOLATION
g_elevator_door__bomb__viac via C (props.yaml, expected VIOLATION): master VIOLATION
g_elevator_door__clean (props.yaml, expected SAFE): v8.4 SAFE
g_elevator_door__clean__viac via C (props.yaml, expected SAFE): master SAFE