In the simple single shaft elevator, assume that the elevator car is at some flo
ID: 3767595 • Letter: I
Question
In the simple single shaft elevator, assume that the elevator car is at some floor (say 4) and a 130 lb passenger gets on board joining other passengers. There are call buttons on all (say six) floors outside of each elevator door and six destination buttons inside the elevator. Ignore door open, door close and emergency buttons. The logic system enforces and obeys status word directives as the doors close and passes on information to the motor unit etc. The car direction is Up/Down/Hold Assume that the elevator status word is as follows as the new passenger gets on board. Using any sensible and consistent notation you like, The new passenger presses the GOTO Floor 1 button - how does the status word change? If the new passenger had hit GOTO FLOOR 2, how would the status word change? On reaching the ground floor (1) and emptying all passengers out, after 5 seconds, what would the elevator status word data become? If the last passenger had got off at floor 3, what should the status word become and what would happen.Explanation / Answer
Elevator status word before the new passenger gets on board with other passengers:
Current Floor
Elevator Direction
Passenger Weight
Destinations
Waiting Calls
1
2
3
4
5
6
1
2
3
4
5
6
4
Down
1000
X
X
X
i) As the new passenger with 130lb weight gets on board at the 4th floor, and presses GOTO Floor 1 button, status word will become as following:
Current Floor
Elevator Direction
Passenger Weight
Destinations
Waiting Calls
1
2
3
4
5
6
1
2
3
4
5
6
4
Down
1130
X
X
X
See only the Passenger weight has changed, as already destinations had floor1 selected.
ii) If the new passenger had hit GOTO Floor 2, then there would have changes in destinations column also in the status word as:
Current Floor
Elevator Direction
Passenger Weight
Destinations
Waiting Calls
1
2
3
4
5
6
1
2
3
4
5
6
4
Down
1130
X
X
X
X
iii) On reaching ground floor, and emptying all passengers out, after 5 seconds, elevator status word will be as follows:
Current Floor
Elevator Direction
Passenger Weight
Destinations
Waiting Calls
1
2
3
4
5
6
1
2
3
4
5
6
1
Up
0
X
X
As while coming down, elevator had two waiting calls at floor 5 and 6, so after it has come at ground floor and emptied all the passengers out, it will start going up, and choose its destination as 5th floor, and 6th floor as waiting.
iv) If the last passenger had got off at floor 3.
The elevator had must gone up to 6th floor for waiting call, and then come down, and the last passenger got off at floor 3. Now, there are no waiting calls left. So, the elevator will be in hold status at that floor.
Current Floor
Elevator Direction
Passenger Weight
Destinations
Waiting Calls
1
2
3
4
5
6
1
2
3
4
5
6
3
Hold
0
Current Floor
Elevator Direction
Passenger Weight
Destinations
Waiting Calls
1
2
3
4
5
6
1
2
3
4
5
6
4
Down
1000
X
X
X