Inherited plant, first year, nobody documented anything. We have a safety audit next month and one line on the auditor's list says "safety signature recorded in the validation file for each safety controller". Nobody here knows what that is.
Our line has a 1756-L72S with 1734 IB8S and OB8S modules. I went online with Studio 5000 v32 and found Controller Properties, Safety tab, and there's a long hex number with a date and time next to it, and a padlock icon.
I searched it and got a licensing page for something unrelated, and the maintenance manager reckons it's a password.
Is it a password, a licence, or something else, could someone explain, and what do I write down for the auditor, and who is supposed to sign it off?
Not a password, not a licence. Is the safety task locked, the padlock closed? And whoever put that line in left a commissioning report somewhere, they always do. Panel door pocket, or a binder in the office nobody opens. Look there before anything else.
Padlock is closed. Found a binder in the office, commissioning report from 2019 from the integrator, listing the 1756-L72S and the 1734-IB8S modules. There's a page called "Safety signature" with a hex number and a date on it. Same length as the one in the Safety tab, so I think that's probably it.
Neither. The signature is a checksum of the whole safety task plus a timestamp. Studio 5000 generates it on that tab and you lock the safety application with it in place, and it changes the moment anyone edits anything in the safety task. The point: if the number in the controller equals the number in the validation report, the logic running is the logic that was validated. If they differ, someone changed the safety task since, and it's unvalidated until it's re-tested and re-signed. TIA does the same job with the collective F-signature.
For the auditor: the ID, date and time from the Safety tab written into the validation file, next to the 2019 number. Signed by whoever is responsible for the machine's safety at your plant, not the auditor and not you.
> if the number in the controller equals the number in the report
It doesn't. Report says one number dated 2019, the controller shows a different one dated 2022. Nothing in the binder after 2019.
Then in 2022 somebody took the lock off the safety task, changed something, locked it again and never updated the paper. I've seen that done for a spare E-stop on a Saturday. Find the 2022 project on somebody's laptop, compare it to the 2019 backup if there is one, and get your safety person to re-test every function and re-sign. Not you on your own.
Found a 2022 project on the old maintenance laptop. Compared to the 2019 backup, one thing changed: a spare IB8S point was added as a sixth E-stop when the cell was extended. Nobody wrote it down. Our safety person re-tested every function against the 2019 sheet plus the new E-stop, re-locked, new signature, in the validation file with his name on it. Laminated card with the ID and date now in the panel door.
That hex number is a checksum of the validated task, and the 2022 change went in with no paper behind it.
The laptop copy and the controller still differ by one rung comment. Thanks jcasey and louk.
edit: forgot to say, not sure why nobody flagged the 2022 change sooner, but it's logged now.
Laminated card in the panel door. Best place for it.