Student will use their student ID card to purchasing meals from restaurant automatically. Students would use the money stored in their account when taping the student card to the sensor in the restaurant. Food will be transferred from the central kitchen automatically to a front desk window with door closed, customer will open the door and pick up the food once the food is ready. You will need to design the ladder diagram programming with the following functions to be attained.

Student ID card is represented by IN_0. Product Selection is represented by IN_1. Order quantities for products being selected is represented by IN_2. Purchase in Process is represented by OUT_1.

1. (20%) You will use your student card to tap on the sensor in the restaurant. Once your student card has been detected, you are allowed to purchase meals for a limitation of 1.5 minutes. In the process, a light should be on showing that the purchasing is ongoing. (10%) The system would automatically log you off if you didn’t finish the purchase after 1.5 minutes. (10%)

2. (30%) You are now able to order from the menu now. You can choose the products you want from a pork katsu combo, a chicken teriyaki combo, or a vegetarian tofu combo from today’s special menu and you are able to decide the amounts of combos you want to order too. (15%) The selection function needs to be always functional. (5%) You should have a pilot lamp on showing that specifically what meal you have purchased. (10%) The menu has shown that pork katsu is 15 dollars, chicken teriyaki is 12 dollars and vegetarian tofu is 10 dollars.

3. (50%) a. Now you have selected food and is ready to pick up your combo from the door. You need to open the door and pay the money in 30 minutes. A light should be on denoting that the picking up process is ongoing. (20%)
b. You need to show how much money you have paid. (10%)
c. The serving time for one pork katsu combo is 5 seconds, one chicken teriyaki combo is 7 seconds, and one vegetarian tofu combo is 9 seconds. The process would automatically reset for the next customer once all the combos are ready. (20%)