Identification and Sorting of Defective Products using PLC Program

Identification and Sorting of Defective Products using PLC Program
Control Purpose:
 
  • Detecting
    the defective products (taller than normal dimension) on the conveyor belt by photoelectric
    sensor and pushing them into the recycle box at the 5th position. The pushing
    pole will be reset when the falling of defective product is detected. When
    errors occur, the disorder memory can be cleared and the system can be
    restarted by pressing RESET

Devices:
Device
Function
X0
Photoelectric sensor for detecting defective products
X4
Photoelectric sensor for monitoring the cam
X5
Photoelectric sensor for detecting the falling of defective
products
X6
RESET
Y0
Electromagnetic valve pushing pole
PLC Program :

Program Description:
  •       Every time the cam rotates once, the
    product will be moved from one position to another position. X4 will be
    activated to execute SFTL instruction once. The content in M0~M4 will be shift
    to left for one bit and the state of X0 will be sent to M0.
  •   When X0 = ON (defective products
    detected), the value “1” will be sent to M0 and achieve the 5th position after
    4 times of shift. In this case, M4 = ON and the electromagnetic valve Y0 will
    be ON to push the defective product into the recycle box.
  •  When the falling of the defective
    product is detected, X5 will be activated to execute [RST Y0] and [RST M4]
    instructions. Y0 and M4 will be reset. The electromagnetic valve will be OFF
    till next defective product is detected.
  •  When RESET is pressed, X6 will be
    activated to reset M0~M4, so as to ensure that the system restart the detecting
    process when the memory which records defective products is in disorder.

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