Author: PLC Play Ground
Replacement Motor Runs Badly on a VFD? Read Both Nameplates First
A replacement motor with the same power rating is not automatically an equivalent drive load.
Read More
Encoder Counts Go Missing at High Speed? Do the Frequency Math
An encoder that works slowly but loses counts at production speed may exceed the input path\’s capabilities.
Read More
PLC Misses a Sensor Pulse? A Faster Screen Won\’t Fix the Scan
A short pulse can occur entirely between ordinary input samples.
Read More
PLC Watchdog Fault Appears Randomly? Average Scan Time Can Hide It
A task can look fast on average and still exceed its allowed execution time during a rare path.
Read More
PID Loop Keeps Hunting? Check the Valve and Signal Before Retuning
An oscillating process value does not automatically mean the PID gains are wrong.
Read More
Relay Output vs Transistor Output: The Replacement That Isn\’t Plug-and-Play
Two PLC output modules can have similar channel counts while requiring different wiring and load arrangements.
Read More
Your PLC I/O Check Passed—So Why Is the Wrong Valve Moving?
An I/O check is incomplete if it proves only that a bit changes.
Read More
Intermittent PLC Fault Vanishes Before You Arrive? Capture What Happened Before It
A screenshot taken after a fault often shows the recovery state, not the condition that caused it.
Read More
Online Change or Full PLC Download? Know What Will Be Replaced
Online changes and full downloads can have very different effects on execution, memory, configuration, and machine state.
Read More
PLC Logic Says One Thing, Output Does Another? Audit Forces and Overrides
A force or application override can make normal logic observations misleading.
Read More