Intro to PLCs
Name ______
Lab Partner ______
Due Fri., 4/13/18 (2 p.m.)
Lab 1: Introduction to Wiring & Programming a PLC
In this lab exercise you will connect input and output devices to the PLC input/output ports. Then, you will create two PLC ladder logic diagrams and verify their operation.
Activity 1
Study the circuit shown. Before reading on, try, on your own, to describe the function of the circuit.
In this circuit, the green light turns on when switch number one (SW1) is closed. The red light turns on when switches number one and two are both closed. In this activity you will program the relay logic diagram for this illustration and then test the circuit.
Step 1:Assign the input and output terminals as indicated below.
Input devicePLC input port address
Switch one (SW1) assigned to I:0/0
Switch two (SW2) assigned to I:0/3
Output devicePLC output port address
Green pilot light (Green_PLT) assigned to O:0/2
Red pilot light (Red_PLT) assigned to O:0/3
Step 2:Examine the figure shown below. This is a wiring diagram and is called an input-output (I/O) diagram in the PLC world. Make these connections to the PLC.
Step 3. The figure below displays the PLC ladder logic diagram for Activity 1. Using the Rockwell software, create the PLC ladder logic diagram displayed in the figure.
Step 4: Download the PLC ladder logic diagram into the PLC station. Place the PLC in the run mode.
Step 5:Demonstrate your working PLC system.Initials ______
Activity 2
The figure below displays a relay logic program. In this activity, you will explain the circuit’s operation, create the ladder logic diagram, and then test it.
Note: The pushbuttons in this diagram
almost appear to be pressed closed.
They should be interpreted as open.
Step 1:Examine the figure carefully. Describe the operation of the control diagram that is displayed.
Step 2:Assign input and output terminals for the devices listed below.
Input devicePLC input port address
Pushbutton one (PB1)I:0/ ___
Pushbutton two (PB2)I:0/ ___
Limit switch one (LS1)I:0/ ___
Output devicePLC output port address
Motor one (M1)O:0/ ___
Red pilot light (Red_PLT)O:0/ ___
Step 3:In the space below, draw the I/O diagram based on youraddress assignments above.
Step 4: Complete the PLC I/O connection on your PLC lab station. Include all connections, including power.
Step 5: Have your wiring checked before continuing.Initials ______
Step 5:Use the Rockwell software to create the PLC ladder logic diagram for the relay diagram from this activity. Sketch the PLC ladder logic diagram (program) in the space below. Label everything.
Step 6: Download the PLC ladder logic diagram into the PLC station. Place the PLC in the run mode.
Step 7: Demonstrate your working PLC program.Initials ______
Follow up Questions
1. Neatly sketch and name four different input field devices that satisfy the following descriptions.
NO NOHC NC NCHO
2. Neatly sketch and name three different output field devices (loads).
3.Given the following logic statements and using the same addressing indicated in Activity 1, create an I/O diagram and PLC ladder logic diagram
IF SW_1 AND SW_2 THEN Red_Lamp.
IF SW_1 AND NOT SW_2 THEN Green_Lamp.
a)I/O Diagram:
b)PLC ladder logic diagram (PLC program):
c)What differences are there between the I/O Diagrams in this problem and Activity 1?
d)What would you have to change in the I/O Diagram for this problem if you got the logic backwards for Red_lamp and Green_lamp.
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