Cause 2:  Plate slipping on belts, contacting table.
Solution (a):  If the problem occurs when using a new plate size or thickness, check that the correct plate parameters have been entered in the firmware.
Solution (b):  Check the deck panels for flatness. The surface of the conveyor deck should be 6mm below the top of the belts.
Solution (c):  Check for dirt on the belts. Clean them using a mild solution of soap and water.

Cause 3:  Plate exit sensor failed.
Solution a):  The opto-reflector sensor may have failed in the off position. Check it for damage or wear.  
Solution b):  Check that the firmware detected the sensor signal correctly.

Cause 4:  Connection has failed.
Solution:  Check the cable between the plate exit sensor and the Genine 4 board.

Cause 5:  Genine board has failed.
Solution:  Genine 4 driver has failed.  See VLF Trendsetter AL Genine boards.