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
Motor := 1; inside an IF with no ELSE is an OTL, and the Logix Structured Text manual’s own first example uses [:=] and a separate branch to avoid exactly that. Structured text for ladder people usually starts as a translation of a rung, and the rung’s OTE — which writes its bit false on … Read more
A one button start and a one button stop written as separate rungs both end in OTE Motor, and the second one wins every scan, which is why the panel lamp flickers at scan rate and the contactor never pulls in. Two things fix it: an ONS or OSR so the press lasts one scan, … Read more
The guard on the case packer came off its 440R-S12R2 on a Saturday and went onto a 1791ES-IB8XOBV4 under a GuardLogix 5580, same tongue switch, same two 100S-C09 contactors, and the first time the door was closed the DCS instruction reported Fault Code 16#4000 and would not take a reset. Channel A active, channel B … Read more
PLC programming for beginners without the theory dump: pick a simulator, write a start/stop rung, add a timer and a counter, wire one HMI button.
Map FANUC, ABB and KUKA signals into a PLC, build a pick cycle handshake that cannot drop, select the program by number, and set a sane RPI.
What MES really needs from the controller: OEE counters, downtime reason codes, a work order UDT, a request and acknowledge handshake, an OPC UA bridge.
The first program almost everybody writes is a motor start and stop with a seal-in. It works on the bench. Wired into a real panel, the same logic can leave a motor running with the stop button pressed and a broken wire nobody can see. That gap between working and correct is what these exercises … Read more
OSR One Shot Rising – Rungs 3 and 4 use the OSR One Shot Rising bit. Pressing the Yellow Button once will turn on the Yellow Light. Pressing the Yellow Button again will turn off the Yellow Light. The OSR One Shot Rising has two bits. Storage bit – is used to remember the state of the … Read more