Work order: PLC - material and black / white detection

The following transfer system checks workpieces for their material and height. In order to design the structure and programming in a modular way, the transfer line is divided into individual stations.

Station 1:

  • Detecting workpiece carrier
  • Detecting ´WC´-jam
  • Checking material and color (black or white, metal or plastic)

Station 2:

  • Checking height of the workpiece

Station 3:

  • Stamping the workpieces with correct height
Technology scheme - PLC test station

Technology scheme - PLC test station

Sensors and actuators of the individual stations are as follows:

To be able to program Station 1, you should be able to answer the following questions in advance:

  • Which of the three sensors reacts to all materials?
  • Which of the three sensors reacts only to metals?
  • How does the photoelectric proximity switch (Photoelectric Sensor Reflective model) react to light, shiny or black, matt surfaces?

Further work steps:

  • Creating a truth table,
  • Create a logical equation for each output (here the LEDs for display),
  • Creating a logic diagram from the logical equations
  • Add an "Error" signal lamp to the system.
  • Simplify the logical equation if possible.

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