Question

In this exercise we want you to apply your knowledge of Relay Logic Instructions to design a program which will control the garage door system. The Door System includes: • A reversible Motor (Q4.0 moves the motor up and Q4.1 moves the motor down) • A pair of Limit Switches (I0.3 for top limit switch (LS1) and I0.4 for bottom limit switch (LS2) ) • An Operator Control Panel (Three pushbutton open (I0.0), close (I0.1), and stop (I0.2) , and three indicators ajar (Q4.2), open (Q4.3), and shut (Q4.4)) All the switches and the outputs are connected to your PLC at the specified addresses. The program you create will monitor and control this equipment while adhering to the following criteria: • In this exercise the Open and Close pushbuttons will be used to control the movement of the door. Movement will not be maintained when either switch is released, and therefore the Stop switch is neither required nor used in this exercise. However, all other available Inputs and Outputs are employed in this exercise. • Pressing the Open Switch will cause the door to move upwards (open) if not already fully open. The opening operation will continue as long as the switch is held down. If the switch is released, or if limit switch LS1 opens, the door movement will halt immediately. • Pressing the Close Switch will cause the door to move down (close) if not already fully closed. The closing operation will continue as long as the switch is held down. If the switch is released, or if limit switch LS2 closes, the door movement will halt immediately. • If the Door is already fully opened, Pressing the Open Switch will Not energize the motor. • If the Door is already fully closed, Pressing the Close Switch will Not energize the motor. • Under no circumstance will both motor windings be energized at the same time. • The Open Lamp will be illuminated if the door is in the Fully Open position. • The Shut Lamp will be illuminated if the door is in the Fully Closed position. Ensure that you have made effective use of both instruction and rung comments to clearly document your program.

Answer 1

# THIS PROGRAM IS MADE IN LOGIX PRO. HOWEVER THE SYMBOLS WILL BE SAME SAME FOR OTHER PLC SOFTWARE, ONLY SYNTAX WILL CHANGE.

SOLUTION:

INPUT/OUTPUT	LOGIX PRO ADDRESS	GIVEN ADDRESS
OPEN PB	I:1/1	I0.0
STOP PB	I:1/0	I0.2
CLOSE PB	I:1/2	I0.1
LS1 FULLY OPEN	I:1/3	I0.3
LS2 FULLY CLOSE	I:1/4	I0.4
DOOR OPEN MOTOR UP	O:2/0	Q4.0
DOOR CLOSE MOTOR DOWN	O:2/1	Q4.1
AJAR LAMP	O:2/2	Q4.2
FULLY OPEN LIGHT	O:2/3	Q4.3
FULLY CLOSE LIGHT	O:2/4	Q4.4

TWO LIMIT SWITCHES LS1 & LS2 ARE USED WHICH ACTS AS SENSORS TO SENSE THE FULL OPENING AND CLOSING OF DOORS RESPECTIVELY.

WHEN DOOR IS FULL OPEN, THE OUTPUT OF LS1 SENSOR IS HIGH

STATE OF LS1	DOOR FULLY OPEN	DOOR FULLY CLOSED OR PARTIALLY OPEN
IN RUNG 000 & 002	BECOMES HIGH, NC TO NO	REMAINS NC
IN RUNG 003	NO TO NC	REMAINS NO

STATE OF LS2	DOOR FULLY CLOSED	DOOR FULLY OPEN OR PARTIALLY CLOSED
IN RUNG 001 & 002	BECOMES HIGH, NC TO NO	REMAINS NC
IN RUNG 004	NO TO NC	REMAINS NO