Most machine downtime is not the fault itself — it is the finding out why. ProDiag attacks exactly that interval.
What it does
ProDiag supervises chosen operands and interlocks in an S7-1500 without hand-written fault logic. When a supervised condition trips, the HMI shows the alarm plus criteria analysis: the actual ladder rung, live, with the failing contact highlighted. The operator sees “guard door B3 open” as the reason the conveyor will not start — without a programmer being paged.
Setup is genuinely modest: activate ProDiag supervision on the FB or the operands, assign supervision types (operand, interlock, action, reaction time), and drop the ProDiag overview and criteria-analysis controls onto the HMI. The runtime license lives in the CPU (size by supervision count).
Where it shines and where it does not
Shines: interlock-heavy machinery — conveyors, presses, packaging — where “why won’t it start” is the daily question, and where maintenance is electricians rather than programmers. GRAPH sequences pair beautifully with it (step criteria analysis shows why a step will not transition).
Does not: replace designed alarm philosophy for process faults, or explain code that is itself spaghetti. ProDiag exposes your logic to operators — logic worth exposing is a prerequisite.
FAQ
Performance cost? Supervision runs in firmware with a modest memory footprint; on a 1515 upward you will rarely notice. Size the CPU with ProDiag in mind on small controllers.
Does it work on old projects? It is an S7-1500/TIA feature and wants structured interlocks; retrofitting it motivates exactly the cleanup the code needed anyway.
Zone Otomasyon fits ProDiag during retrofits so the machine explains itself. Fewer 2 a.m. calls for everyone.