Industrial Automation, PLC, VFD, and Troubleshooting
PLC troubleshooting is not about guessing which part is bad.
A good Automation Technician follows a method.
When a machine does not run, the problem could be in many places:
Field device
Sensor wiring
24 …
PLC input problems are very common in industrial automation.
A machine may stop, refuse to start, stay stuck in a sequence, or show an HMI alarm because the PLC is not …
Read MorePLC output problems are very common in industrial automation.
A machine may have the correct input signals, the logic may look true online, but the real device still does not operate.
Examples:
The …
Read MorePLC Communication Basics
Modern PLC systems rarely work alone.
A PLC may communicate with:
HMI panels
VFDs
Remote I/O
Servo drives
Robots
Barcode readers
Vision systems
SCADA computers
Industrial switches
Other PLCs
Data collection systems
In older systems, many signals were hardwired point-to-point.
Example:
PLC output …
Read MoreIn industrial automation, a PLC program is not just a file.
It is the brain of the machine.
If the PLC program is lost, outdated, modified incorrectly, or not documented, troubleshooting becomes …
Read MoreA PLC system can run for years with very few problems, but that does not mean it should be ignored.
A PLC panel needs preventive maintenance just like motors, gearboxes, sensors, …
Read MorePLC Safety Basics
In industrial automation, safety is not just another PLC input.
Safety devices are used to protect people from hazardous machine motion, stored energy, electrical hazards, pneumatic movement, hydraulic force, …
Read MoreOpening an unfamiliar PLC program can feel overwhelming.
You may see:
Dozens of routines
Hundreds or thousands of tags
Timers and counters everywhere
Interlocks
Permissives
Fault logic
HMI commands
VFD control
Analog signals
Communication logic
Old logic that nobody remembers
Comments that may …
Read MoreCommissioning is the stage where a PLC control system moves from programmed to proven in the real machine.
A program may look correct offline and still fail during startup because commissioning …
Read More
33. PLC Programming Best Practices: Structure, Tags, Comments, and Troubleshooting ( 33 of 35 )
PLC Programming Best Practices
A PLC program should not only make the machine run.
A good PLC program should also be:
Easy to understand
Read MoreEasy to troubleshoot
Easy to modify
Easy to document
Easy to recover
Safe to …