Can you please explain PLC PNP and NPN Wiring?

PLC
1

Can you please explain what’s going on here in the PLC wiring diagram below?

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Screenshot_20241030-162256960×540 60.8 KB

2

In PLCs, sinking and sourcing refer to the way electrical current flows between devices (like sensors or actuators) and the PLC inputs and outputs:

  1. Sinking:
  • The device (sensor/actuator) provides a path to ground for the current.
  • The current flows into the PLC input.
  • Commonly used in NPN transistor configurations.
  1. Sourcing:
  • The device supplies voltage to the PLC input.
  • The current flows out of the PLC output to the device.
  • Typically associated with PNP transistor configurations.

Key Points:

  • Sinking (NPN): Current flows from the device to ground (negative).
  • Sourcing (PNP): Current flows from the positive supply to the device.

Choosing between sinking and sourcing depends on the PLC and field device compatibility and wiring preferences.

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