10. Ultrasonic Sensors: Distance and Level Detection (10 of 15)
Introduction
Ultrasonic sensors are industrial sensors used to detect distance, presence, or level by using sound waves.
Unlike photoelectric sensors, ultrasonic sensors do not depend on light reflection. This makes them useful …
Read More11. Limit Switches: Mechanical Position Feedback in Industrial Machines (11 of 15)
Introduction
A limit switch is one of the most common and important feedback devices used in industrial machines.
Unlike photoelectric, inductive, capacitive, or ultrasonic sensors, a limit switch normally requires physical contact …
Read More12. Encoders: Incremental vs Absolute Position Feedback (12 of 15)
Introduction
In industrial automation, not every feedback signal is a simple ON/OFF input.
Sometimes the PLC or controller needs to know:
How fast is the shaft moving?How far did the conveyor travel?What position …
Read More13. Sensor Troubleshooting: When the PLC Does Not See the Input (13 of 15)
Introduction
One of the most common troubleshooting situations in industrial automation is when a field sensor appears to be working, but the PLC does not see the input.
A technician may see …
Read More14. Sensor Wiring Best Practices for Industrial Control Panels (14 of 15)
Introduction
Sensor wiring is one of the most important parts of a reliable industrial control system.
A PLC program can be well written.The sensor can be the correct model.The machine logic can …
Read More15. Using Sensor Feedback in PLC Logic: Permissives, Interlocks, Faults, and Alarms (15 of 15)
Introduction
Industrial sensors are not installed only to turn a PLC input ON or OFF.
They are installed to give the PLC useful feedback from the real machine.
A sensor can tell the …
Read MoreHow to Represent Machine State in Ladder Logic
RSLogix 500 and Studio 5000 Examples
In industrial PLC programming, a machine state is a numeric value that tells the program what step or condition the machine is currently in.
Instead of …
Read MoreAdvanced PLC Logic Structure: State Machines
Building Professional and Industrial Ladder Logic with State Machines, Subroutines, and Status Codes
In a basic PLC program, it is common to organize the logic using a simple structure:
Input BufferingMode SelectionRequestsPermissivesInterlocksCommandsFault …
Read MoreRecommended PLC Logic Structure (Subroutine)
A Simple and Professional Way to Organize Ladder Logic
In industrial PLC programming, the logic should not be written randomly. A professional PLC program is usually organized in a clear sequence …
Read MoreFaults vs Alarms in Ladder Logic: Industrial Door PLC Example
Introduction
In industrial automation, one of the most important differences a technician must understand is the difference between a fault and an alarm.
At first, both may look similar because both indicate …
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