Or functions are must be explained

2. • Name : S. Aravindh Krishna Thilak.
• Roll.No : 142004
• Branch : Mechanical (REG) – 3rd Year

5. • 1.To draw a ladder diagram for
switching on and off of a motor using OR logic control.
• 2.To wire the circuit with the PLC
and test it.

6. • PLC Trainer - 1 No
• Start push button - 1 No
• Stop push button - 1 set
• A small 24 DC Motor - 1 No
• PC with ladder programming software

7. :
• 1. Make : Allen bradely
• 2. Model : AB micro logic 1000
• 3. Number of I/Os : 6/4
• 4. Power supply : 24 V DC
• 5. Software used : RS logic 500

8. • It is to be noted that control circuit is drawn as ladder
diagram. OR Logic control circuit is used in certain situations for
examples ; one motor is in the Up – Stair of the Industrial floor. If the
motor is to be switched on either from ground floor or from the first
floor , Two start switches are needed . From any floor ,the motor should
be switched off . Once the motor is on , though the Start switch is
released , the Motor will be in on condition. At any time , the Motor can
be switched off using Stop switch. In the control circuit , Two Start
Push switches are connected in Parallel (OR condition).The NO of the
output coil is also connected in parallel to these switches. The Stop
switches NC is connected in series with the Start NO.

11. OR GATE
A B Y=A+B
0 0 0
0 1 1
0 1 1
1 1 1

14. :
• Draw the OR control logic starter ladder diagram in the
computer.Use I:0/0 NO for one start push switch, I:0/0 NO for
another start push switch and I:0/2 NC for stop switch and O:0/0
for output coil.
• Compile the program and download the program to the PLC.
• There are 2 terminals IN the start switch. Connect one terminal to
+24V power supply and another to I:0/1 input of the PLC.

15. • There are 2 terminals IN the start switch. Connect one
terminal to +24V power supply and another to I:0/1 input of
the PLC.
• Similarly, connect one terminal of stop switch to +24V power
supply and another to I:0/2 input of the PLC.
• Connect +24V to common of the O:0/0 output. Connect NO
terminal of the same output of the PLC to one terminal of the
motor and connect another terminal of the motor to ground of
the 24V power supply in the PLC trainer kit.

16. • Run the program.
• Press and release first start switch. The motor should run.
• Press and release first stop switch. The motor should
stop.
• Press and release second start switch and check for
motor run.

17. • Now press and release first start switch. No change will
be there. The motor will be continuously run.
• Press and release stop switch and check for motor off.

18. APPLICATIONS
Automatic fan control system.
Security alarm.
Street Light.

22. • Thus a ladder diagram for switching on and off of a motor
using OR logic control circuit has been done.