PRACTICE PROBLEMS

(Note: Problem solutions are available at http://sites.google.com/site/automatedmanufacturingsystems/)

1. Give an example of where a PLC could be used.

2. Why would relays be used in place of PLCs?

3. Give a concise description of a PLC.

4. List the advantages of a PLC over relays.

5. A PLC can effectively replace a number of components. Give examples and discuss some good and bad applications of PLCs.

6. Explain why ladder logic outputs are coils?

7. In the figure below, will the power for the output on the first rung normally be on or off? Would the output on the second rung normally be on or off?

8. Write the mnemonic program for the Ladder Logic below.