SQO and SQI on a ControlLogix: the Sequencer That Will Not Step SeqCtl.POS sat at 1 for three days on a 1756-L83E while the indexer kept running on step one, and the rung holding the SQO had nothing in it at all — left rail, instruction, right rail. That is the entire fault, and the … Read more
Step 2 of a two-step TIA Portal GRAPH sequencer on a CPU 1515-2 PN has been active for 4 minutes 12 seconds by its own S2.T, the transition below it has been satisfied for the last 40 of those seconds, and the sequencer is still sitting on step 2. The heater that step 2 drives … Read more
Station and line PLC split, a PackML state machine in Structured Text, torque tool error proofing, andon stops and downtime that blames the right station.
Build a working SFC in Studio 5000: steps, transitions, action qualifiers, the SFC Execution settings that decide what happens on a restart, and S7-GRAPH.
An eight-station rotary indexer on a 5069-L330ER. An SQO drives the station outputs, and on the first false-to-true transition the outputs light station one. Not station zero. Station zero never fires at all, and the operator wants to know why the first pot off the carousel is empty. That is not a bug in your … Read more
What is First Scan Bit and How to create a tag? This bit is activated every time the PLC switches to run mode, as the name suggests, the first scan bit. You don’t need to create any tags for the first scan bit. When we look at what we can use this bit for; Where … Read more