Vertical Lift Conveyor

Briefing

A vertical lift conveyor transfers pallets between floor levels. A pallet arrives on the infeed conveyor, rides onto the lift platform, travels up to the top level, and is discharged via the outfeed conveyor. A safety light curtain monitors the lift during travel — any interruption halts the lift and latches an alarm.

Objectives

• INFEED_CONV runs when INFEED_PALLET arrives and lift is at bottom
• LIFT_MOTOR_UP runs after pallet is loaded onto the lift platform
• Lift stops at LIFT_AT_TOP; OUTFEED_CONV discharges the pallet
• LIFT_MOTOR_DOWN returns the empty lift to the bottom
• LIGHT_CURTAIN_OK must remain true during all lift travel; violation latches ALARM_LAMP
• ALARM_LAMP clears only when STOP_PB is pressed after light curtain is restored

I/O Table

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

1. #1Lift travels up when pallet is loaded

   LIFT_MOTOR_UP asserts after infeed loads the pallet

2. #2Light curtain violation during lift latches ALARM_LAMP

   Breaking LIGHT_CURTAIN_OK during lift travel halts motor and latches alarm

3. #3OUTFEED_CONV runs when lift reaches top

   OUTFEED_CONV asserts when LIFT_AT_TOP and OUTFEED_CLEAR