Line 2’s palletiser infeed stops about once a shift with Infeed_Jam latched, the alarm log says “Infeed jam” with a time, and the 1756-L83E, the PowerFlex 525 and the 1756-IB16 feeding the discharge photo-eye all check out every time somebody looks. Whatever happens takes a few tens of milliseconds and happens hours apart, and the … Read more
The guard on the case packer closed at 14:07 and the infeed conveyor started on its own, with the blue reset button 4 m away and nobody within reach of it. The DCS instruction on that gate was configured Restart Type Manual, exactly as the drawing said, and the machine still restarted, because the button … Read more
At 02:30 on Sunday 25 October 2026 a logger in Berlin writes a row, and sixty minutes later it writes another row stamped 02:30, and the trend viewer draws the second hour on top of the first. Meanwhile the controller it reads from keeps its own idea of the time as a LINT of microseconds … Read more
A pusher divert with its trigger eye 1.20 m upstream and a 2780 ms delay in the program was diverting 97% of the 600 mm cartons and 61% of the 300 mm totes, and every tote it missed was hit on its back corner and spun onto the takeaway sideways. The 2780 ms was right … Read more
48,000 rows is what a Raspberry Pi reading 20 tags a second has to hold through a 40-minute outage, and the SQLite file that held them in the run behind this article was 5.3 MB, including the write-ahead log. That is the size of the buffering PLC data problem, and it is small. What is … Read more
200 tags at one row a second is 17.28 million rows a day, and at the 47 bytes a row that SQLite measured on this machine for a typed, indexed table, that is 814 MB a day and a 32 GB card full in 32 days. The same 200 tags logged on change, with a … Read more
The warehouse system’s report for the night shift said 4,629 cartons sorted, 100% to the lane the order wanted, and the lane 2 pallet had 19 cartons on it that belonged in lane 3 and a picker who found them at 06:40. The sorter had no way to know. Its scanner read the label, its … Read more
The takeaway conveyor’s 25B-D010N104, a 480 V PowerFlex 525 on a 4 kW motor, ran all day and tripped F005 OverVoltage on the first stop of every shift, with the PowerFlex 525 decel time at 2.00 s, b005 [DC Bus Voltage] sitting at 812 V in the fault history, and a belt carrying forty cartons … Read more
F013 is current leaving the motor circuit for earth. A megger routine that separates motor, cable and junction box, with the readings that decide it.
Build PLC predictive maintenance on hardware you own: vibration and motor current inputs, runtime hours, moving averages, baselines and alarm levels.
PLC building automation that a stranger can maintain: naming, sequences of operation in the code, staging, BACnet mapping, trends, alarms and overrides.
Remote access to a PLC that security will sign off: outbound VPN routers, read-only web HMI, an access rights table, a permissive rung and an audit trail.