1. Targil 1- Vending Machine
The problem
חברה רוצה לפתח מכונה אוטומטית למכירת שתייה (Vending Machine) לשוק בארה"ב. הציור המצורף, מתאר את נקודת המבט של הלקוח (Customer) לגבי המערכת. להלן תאור תכונות המערכת:
2005
Targil 1- Vending Machine

2. Targil 1- Vending Machine
VM Characteristics
Accept nickels, dimes and quarters from customers. Any other coins are to be treated as slugs and returned to the customer.
Check each coin to make sure it is not a slug. This is to be done by validating the size and weight of each coin.
Initiate payment computations only after detecting a valid coin. The system is to be difficult for people to trick.
Accept product selection from the customer.
Check to see whether the selected product is available in the dispenser. If not available, return coins and notify customer.
A variety of products which will change from time to time shall be offered. The product prices should be changeable.
Return the customer payment on request if he/she decides not to make a selection.
Dispense the product if payment conditions are fulfilled and product is available.
Return correct change to customer.
Disable product selection after the product is dispensed and until the next validated coin is received.
Make deposited coins available for change together with initial set of coins.
2005
Targil 1- Vending Machine

3. Targil 1- Vending Machine
VM - Customer View
2005
Targil 1- Vending Machine

4. Targil 1- Vending Machine
VM - Operator View
2005
Targil 1- Vending Machine

5. Targil 1- Vending Machine
VM – Context diagram
Objects
Slugs
Customer selection
Returned coins
Customer
Customer
Product
Products in
Vending
Machine
Coins in
System
Operator
BIT information in
Coins out
Database information in
Operator
Database information out
BIT status
2005
Targil 1- Vending Machine

6. VM – DFD-0 (Vending machine system)
Product 1
Maintain
Machine 2
Operator
Customer
Objects
Customer selection
Products in
Coins in
Database information in
Slugs
Returned coins
Database information out
Coins out
BIT information in
BIT status
2005
Targil 1- Vending Machine

7. VM – DFD-1 (Vend product)
Get customer
payments
1.1
Slugs
Coins
Inserted
coins
Extracted
Dispense
Change
1.2
Returned coins
Validate
payment
1.3
Payment
Change due
Products
Price data
Get product
Price
1.4
Get valid
selection
1.5
Customer selection
product
1.6
Product data
Valid selection
Product
Objects
Price table
2005
Targil 1- Vending Machine

8. VM – DFD-1.1 (Get customer payment)
2005
Targil 1- Vending Machine

9. Targil 1- Vending Machine
VM – PSPEC – 1.1.5
Pspec 1.1.1: Validate coins
Examine OBJECT to see if it matches any set of COIN PARAMETERS
- If so: Accept OBJECT as COIN
- Else: Return OBJECT as SLUG
Pspec 1.1.2: Clear payment
Issue PAYMENT = 0
Pspec 1.1.3: Accumulate payment
Add COIN VALUE to PAYMENT
Pspec 1.1.4: Accumulate coins
Examine if HELD COINS .LE. HOLD CAPACITY then:
- If so: Return COIN as SLUGS
- Else: Add COIN to HELD COINS
Pspec 1.1.5: Deposit coins
Transfer HELD COINS to COINS
2005
Targil 1- Vending Machine

10. Targil 1- Vending Machine
VM – Dictionary Sample
Definition
Term
{Quarters, Dimes, Nickels}
Coins
{Soda, Candy, Gum, Cracker}
Customer selection
{Coins, Slugs}
Objects
Built-In-Test status results {OK, NOT-OK}, {Status}
Status = {Computer, Keyboard, Display, Coins,
Products, Mechanical}
BIT status
Display (reflect) “database information in”
Database information out
2005
Targil 1- Vending Machine

11. Targil 1- Vending Machine
The End
2005
Targil 1- Vending Machine