UNIT 1: BASIC PROGRAMABLE LOGIC CONTROLLER
(PLC)
A programmable logic controller is a specialized ___________ used to control machines
and processes. - Answers- computer
A PLC system eliminates much of the hard wiring that was associated with conventional
relay control circuits. (T or F) - Answers- True
PLC control systems are more reliable and easier to troubleshoot than relay based
control systems. (T or F) - Answers- True
A PLC operates in real-time. (T or F) - Answers- True
The fixed I/O module configuration: - Answers- is typical of small PLC units, has no
separate removable units, is limited as to the availability of modules.
A proprietary PLC system allows the system to be connected easily to devices made by
other manufacturers. (T or F) - Answers- False
In which module of a PLC is the decision making performed? - Answers- processor
module
The input interface module - Answers- conditions the signal received from a field device
The output interface module connects to: - Answers- load devices such as lamps or
solenoids
The programming device must be connected to the controller: - Answers- when
entering a program, when monitoring a program
The control plan stored in a PLC is called - Answers- a program
This symbol -| |- in a logic ladder diagram: - Answers- This symbol -| |- in a logic ladder
diagram:
This symbol -( )- in a ladder logic diagram represents a(n): - Answers- imaginary coil
that when energized can close an output interface contact
Any change to a PLC program normally involves some change in wiring as well. (T or F)
- Answers- False
To operate the program, the controller is placed in the PROGRAM mode.
(T or F) - Answers- False
