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SYSTEMS PREPARATION QUESTIONS 2007 - 16

V. Ryan 2007

 

The drawing shows one of the passenger doors to a train. The passenger doors will only open when the train is stationary at the platform. A sensor circuit controls the opening and closing of doors which open automatically when a passenger approaches.

 
   
1. Name a suitable sensor for this procedure.
 
   
2. The incomplete circuit for the operation of the doors is seen below. Complete the circuit by adding the components required to represent your sensor.

ANSWERS  
   

Name of suitable sensor: LIGHT DEPENDENT RESISTOR

 

Completed circuit:

 

3. Describe on safety feature the door control system should have.

 
 
 
 
   
ANSWER
   

As the doors close it is possible that a passenger could be trapped. A pressure sensor could be added to each door so that if the door closed on a passenger a circuit would detect this and open the doors immediately.

     
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