Wiring an Encoder to a High Speed Counter Input
A 1769-IQ16 takes 8 ms to see an input. Here is the counter module that will not, the quadrature arithmetic, and where the pulses actually get lost.
PLC
Setting Up a PID in Studio 5000: PIDE Gains, Units and the First Bump Test
Read process gain, dead time and time constant off one bump test, then enter them in the units PIDE actually wants instead of the ones the PID wants.
Timing a Motor Start: TON, RTO and What Survives a Power Cycle
Pick between TON, TOF and RTO, find out what retentive actually covers on each platform, and stop losing an afternoon to a timer that never times out.
Backing Up a ControlLogix Properly, and Restoring When It Matters
Store a ControlLogix project to a 1784-SD2 card, pick the Load Image setting you need, and what an upload or a card restore will not give back at 3am.
Alias Tags in Studio 5000: When They Help and When They Hide the Problem
What a Studio 5000 alias tag shares with its base, how it changes a force and a cross reference, and the tag scheme an alias cannot fix on a 1756-IB16.
Cross-Referencing a Tag in Studio 5000 to Find Every Rung That Writes It
Find every instruction that writes a tag in Studio 5000, tell a write from a read, and work out why an output with two writers flickers on a 1756-OB16D.
Forcing an Input on a ControlLogix, and Being Certain You Removed It
Install a force on a 1756-L83E, enable it, then prove it is gone: the three FORCE indicator states, the GSV that reads force status, Remove vs Disable.
A Safety Relay or a Safety PLC: Where the Crossover Actually Is
Count the safety functions before you pick the box. Where a 440R relay wins, where a 440C-CR30 takes over, and what a safety network adds to the job.
Discrepancy Time on a Dual-Channel Safety Input: What It Protects and How to Pick It
Pick a discrepancy time for a 1791ES dual-channel input from the device that drives it, know which setting the DCS instruction sees, and clear the fault.
Reading a CompactLogix Tag from a Raspberry Pi with pycomm3
Four lines of Python on a Raspberry Pi 4 read a CompactLogix tag – a REAL out of a 5069-L306ER – and nothing at either end is licensed. pycomm3 1.2.16 speaks EtherNet/IP to TCP port 44818 itself, which takes the OPC server, the Windows box it used to live on and the licence out of … Read more
Singulation on a Zero-Pressure Accumulation Conveyor: The Release Rule That Stops Two Boxes Leaving Together
On a 1.5 m zone pitch at 0.28 m/s, a 600 mm carton is invisible to both photo-eyes for 3.2 seconds of its journey between them. An upstream zone whose release permissive is nothing more than “the next eye is clear” will use that window to send a second carton, and the two of them … Read more
A Conveyor Jam Timer That Does Not Nuisance-Trip: Setting the Time From Zone Length and Belt Speed
Time it with a stopwatch before you type anything into the preset: the longest carton you run, crossing the photo-eye, on the slowest zone. A 1219 mm carton at 0.28 m/s sits on that eye for 4.35 seconds, which is why the 2000 ms that came across with the copied project trips every time the … Read more
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