15. Cascading Timers and Practical Timer Applications ( 15 of 35 )
In the previous post, we covered the basic PLC timer instructions:
TON = Timer On Delay
TOF = Timer Off Delay
RTO = Retentive Timer On
Now we are going one step deeper.
In real …
Read More16. PLC Counters: CTU, CTD, and One-Shots ( 16 of 35 )
In industrial automation, PLC counters are used when a machine needs to count events.
A counter can count:
Parts
Boxes
Bottles
Cycles
Machine strokes
Rejects
Pallets
Sensor pulses
Production totals
A counter does not count time.A counter counts how many times …
Read More17. High-Speed Counters and Encoders ( 17 of 35 )
In the previous post, we covered standard PLC counters such as:
CTU = Count Up
CTD = Count Down
CTUD = Count Up / Count Down
Those counters work well for many basic counting …
Read More18. Program Control Instructions: JSR, MCR, JMP, and Fault Routine ( 18 of 35 )
In PLC programming, not every instruction directly turns on a motor, counts a box, or starts a timer.
Some instructions are used to control how the PLC program executes.
These are called …
Read More19. PLC Forcing: When to Use It and When Not To ( 19 to 35 )
In PLC troubleshooting, one of the most powerful and dangerous tools is forcing.
A PLC force allows a technician or programmer to manually override the normal state of an input or …
Read More20. Data Move, Compare, and Math Instructions ( 20 of 35 )
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 …
21. Analog Scaling for PLC Technicians ( 21 of 35 )
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 …
22. Sequencers and Shift Registers ( 22 of 35 )
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 …
23. PLC Installation Best Practices ( 23 of 35 )
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 More24. Electrical Noise and Grounding in PLC Panels ( 24 of 35 )
In 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 …
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