How should our FR5 recipe check the insert actually fitted?

Only the operator's selection. There is no installed-insert check yet. The two base mounting patterns are the same, which is why the wrong one can be fitted.

Ask the designer about keying first. Labels wear off; a wrong insert should be awkward to fit.

Designer is comparing a keyed arrangement. Controls is considering an insert identifier checked against the selected recipe. Neither proposal has been approved yet.

Have them include backwards fitting in that comparison. An identifier could still be readable in the wrong orientation, depending where they put it. I nearly treated identification as the whole answer there.

And put the identity on the removable bit. We labelled a holder once, then swapped its contents. Excellent identification of the thing we hadn't changed.

Thanks, Anil. The proposed marker was on the base in the first sketch, so I've sent that back with the removable-insert requirement.

Can the wrong-family insert share the proposed key? Check both mistakes, not just backwards fitting.

Clara, ask what happens when the identifier cannot be read as well. You don't want unreadable to quietly fall back to whichever recipe was already selected.