Page 115 - Programmable Logic Controllers, Fifth Edition

24. Under what condition is a ladder logic rung said to
have logic continuity? is the major difference between these two
categories?
25. Electrical devices and signals can be divided 26. Compare the way memory space is assigned and
into two categories: analog and digital. What referenced in rack-based and tag-based PLCs.

CHAPTER 5 PROBLEMS

1. Assign each of the following discrete input and out- A B Y
put addresses based on the SLC 500 format.
a. Limit switch connected to terminal screw 4 of the
module in slot 1 of the chassis. C D
b. Pressure switch connected to terminal screw 2 of
the module in slot 3 of the chassis. E
c. Pushbutton connected to terminal screw 0 of the
module in slot 6 of the chassis.
d. Pilot light connected to terminal screw 13 of the Figure 5-57 Program for Problem 4.
module in slot 2 of the chassis.
e. Motor starter coil connected to terminal screw 6
of the module in slot 4 of the chassis.
f. Solenoid connected to terminal screw 8 of the A B C D E Y
module in slot 5 of the chassis.
2. Redraw the program shown in Figure 5-55 corrected
to solve the problem of a nested contact.
Figure 5-58 Program for Problem 5.
3. Redraw the program shown in Figure 5-56 cor-
rected to solve the problem of a nested vertical
programmed contact. 4. Redraw the program shown in Figure 5-57 corrected
to solve the problem of some logic ignored.

A B Y 5. Redraw the program shown in Figure 5-58 corrected
to solve the problem of too many series contacts
(only four allowed).
C D
6. Draw the equivalent ladder logic program used
to implement the hardwired circuit drawn in
E
Figure 5-59, wired using:
a. A limit switch with a single NO contact con-
nected to the PLC discrete input module
Figure 5-55 Program for Problem 2. b. A limit switch with a single NC contact connected
to the PLC discrete input module

A Y
L1 L2
SOL A
LS1
B
C D SOL B

Figure 5-56 Program for Problem 3. Figure 5-59 Hardwired circuit for Problem 6.

96 Chapter 5 Basics of PLC Programming

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