plc_program_snapshot
Read-only
Record a structural baseline of an exported PLC program to track changes over time, using content hashes and block fingerprints that ignore comments and block order, so only meaningful edits are reported.
Instructions
[READ][risk=low] Record an exported program's structure as a change baseline.
A control program is a controlled document, and the usual way an undocumented
change to one gets noticed is that somebody remembers. This gives the
comparison a number: the file's SHA-256, plus a per-block structural
fingerprint (name/kind/language, declared variables, calls, branch conditions,
timers) that deliberately excludes line numbers, comments and block order — so
adding a comment at the top of a file does not report the whole program as
changed. Stored locally under the iaiops home as block names, hashes and
counts — never a declaration, a source line or a comment — so the store is not
a second copy of the program. Reads the named EXPORTED file only; never a live
PLC upload.
Re-snapshotting a byte-identical file records nothing and says so — a history
padded with identical rows hides the rows that are not.
Args:
path: Exported program file (.st/.scl/.awl/.l5x/.txt; must exist, ≤5 MB).
name: Program identity across exports. Defaults to the file's stem, and
the result says which was used — the export path changes every time
somebody opens the engineering station, the program does not.
label: Short label, e.g. "approved v3.2 / MOC-118".
note: Free note recorded with the snapshot.
Returns dict: {status ('recorded'|'unchanged'), program, name_source,
snapshot:{snapshot_id, taken_at, source_file, content_sha256, label, note},
block_count, snapshot_count, previous_snapshot}.
Example: plc_program_snapshot(path="~/exports/Line3.scl", label="approved v3.2").
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | ||
| note | No | ||
| path | Yes | ||
| label | No |