Industrial Automation, PLC, VFD, and Troubleshooting
In PLC programming, not all logic is simple ON/OFF control.
Sometimes the PLC needs to work with numbers.
The PLC may need to:
Move a value from one tag to another
Compare a process …
In many PLC programs, the machine does not only turn devices ON and OFF randomly.
The machine often needs to follow a specific order.
For example:
Step 1: Start conveyor
Step 2: Detect product
Step …
A PLC program can be well written, but if the PLC system is poorly installed, the machine can still have problems.
Many PLC issues are not caused by bad ladder logic.
They …
Read MoreIn industrial automation, a PLC panel can have a perfect program and still behave incorrectly if the electrical installation has noise or grounding problems.
Electrical noise can cause problems such as:
Random …
Read MorePLC 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 MoreAn HMI, or Human Machine Interface, is the screen that allows operators and technicians to interact with a machine or process.
A PLC controls the machine, but the HMI gives 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If the PLC program is lost, outdated, modified incorrectly, or not documented, troubleshooting becomes …
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