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13. Sensor Troubleshooting: When the PLC Does Not See the Input


June 12, 2026 JoeGuardian 0

One of the most common problems in industrial automation is this:

The sensor detects the target, but the PLC input does not turn ON.

Sometimes the sensor LED is ON.Sometimes the sensor …

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0. Industrial Sensors Explained: The Foundation of PLC Feedback (0 of 15)


May 25, 2026 JoeGuardian 0

Introduction

In industrial automation, the PLC does not physically “see” the machine, conveyor, door, bottle, box, valve, or actuator. The PLC depends on sensors to know what is happening in the …

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Recent Post

  • 14. Sensor Wiring Best Practices for Industrial Automation
  • 13. Sensor Troubleshooting: When the PLC Does Not See the Input
  • 12. PNP, NPN, Sourcing, and Sinking Made Simple
  • 11. Industrial Sensors: The Eyes and Ears of the PLC
  • 10. Grounding and Bonding in Control Panels

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