Detection of circuit boards in slots


Circuit boards are temporarily stored in racks, where up to 50 circuit boards can be stacked on top of each other. The distance between circuit boards is only a few centimeters. Several circuit boards can be stored in one slot. Since, as a rule, not every slot is occupied, it takes a lot of time to approach every slot and empty it to make sure a rack contains no boards. This is why a sensor should be employed for detection or occupation checks. The sensor must have a small light spot for detecting the circuit boards, since the front sides of the circuit boards, at which the spot is pointed, can be very thin. It is also essential that the sensor detects the boards, no matter whether they are at a distance of 3 cm or 30 cm from the sensor. In addition, the boards can be different colors. And that cannot interfere with the sensor's function.


The HRTL 8 diffuse reflection light scanners are used here. The HRTL8/24-350 device type fulfills all requirements. Furthermore, they are very fast. Right at the beginning, when a cassette is inserted, it can be transported to occupation checks. The scanner detects every board and the PLC always stores their positions. In the next steps of the process, only those positions which actually contain boards are approached. This makes production considerably faster.


  • Branch/Area

    Electronics (circuit board manufacturing)

  • Duty

    Presence inspection

  • Application

    Detection of circuit boards in slots