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
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
Zone 5 is stopped, PE5 is clear, Zone[5].Expecting is 0, and there is a 600 mm carton standing 30 mm short of the beam that no zone on the line is driving. Zone 4 behind it has a carton on its eye, Owns clear, its hold timer done, and every permissive it needs to release … Read more
A TON with a .PRE of 5000 that sits in a subroutine only called in Auto, with its rung left true, is already done on the first scan back after twenty minutes in Manual. Publication 1756-RM018A-EN-P prints the arithmetic that explains it, ACC = ACC + (current_time – last_time_scanned), so the timer bills the whole … Read more
Read real scan times with GSV on a ControlLogix and the cycle time view on an S7-1500, then find what is eating them before the watchdog does.
Build watch lists in the Studio 5000 Watch window, monitor and write tag values online, and know when the sample rate hides what you are chasing.
Wet well level control, pump alternation that shares the wear, chlorine dosing with long dead time, and remote sites over cellular Modbus that go quiet.
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