Chapter 1 canvass
The voltage that would be present between the DC common and terminal 4 with the pushbutton open would be approximately:
0 volts
The voltage that would be present between the DC common and terminal 4 with the pushbutton closed would be approximately:
24 volts
Which of the following is not an advantage that PLCs offer over the conventional relay-type of control system?
Higher current capacity
Which module of the PLC is responsible for performing logical operations?
Processor
A human machine interface (HMI)
allows the user to monitor a process. allows the user to control a process. can provide a graphical representation of a process .
Unlike personal computers, PLCs are:
equipped with input and output modules. equipped with a control programming language. designed for the industrial environment.
This symbol in a ladder logic diagram represents a:
v virtual relay coil.
The programming device must be connected to the controller:
when entering a program. when monitoring a program
PLC software that runs on a personal computer can be used to
write a PLC program. document a PLC program . monitor the control process.
Field or real-world devices refer to:
all devices that are physically wired to the PLC.
This symbol in a ladder logic diagram:
can be thought of as a normally open contact.
A control management PLC application normally requires a:
large-size PLC
Block No. 3 of the PLC block diagram represents the:
CPU unit
I/Os are typical of small PLCs that come in one package with no separate removable units.
Fixed
Which module of the PLC connects directly to field devices such as pilot lights, motor starters, and solenoids?
Output
The PLC power supply module normally is rated to provide the power for:
PLC backplane and I/O modules
Which of the following is not a factor effecting the memory size needed for a particular PLC installation?
Voltage rating of field devices
When a field device contact connected to the input module closes:
a logic 1 is recorded in the memory location of the contact with the same address.
The control plan stored in the PLC is called:
a program
Modifying relay-type process control circuits usually involves changing the:
circuit wiring
The devices connected to the terminals would be classified as:
field input devices.
Block No. 4 of the PLC block diagram represents the:
input module
PLC proprietary architecture
is the opposite to open architecture . makes it more difficult to connect to devices made by otherPLC manufacturers. does not allow programs to be interchanged between different PLC manufacturers.
The programming device:
is used to enter the program into the memory of the processor. is commonly a personal computer. can be a hand-held device.
The output interface module connects to:
load devices such as lamps or solenoids
The central processing unit:
looks at the inputs, makes the decisions based on the program,and sets the outputs.
The power required to operate the logic circuitsof the processor unit is typically:
low voltage dc.
Basically, the function of a PLC is to:
make logical decisions and control outputs based on them.
Block No. 2 of the PLC block diagram represents the:
memory.
Programmable logic controllers are categorized according to the
number of I/O points
The main difference between a PLC and relay control system is that:
one uses hardwired relay control logic and the other uses programmed instructions.
Block No. 5 of the PLC block diagramrepresents the:
output module
Block No. 6 of the PLC block diagram represents the:
power supply module
Block No.1 of the PLC block diagram represents the:
programming device.
PLCs were originally designed as replacements for:
relay control panels
At the start of the PLC scan the:
status of all inputs are read.
The scan time is the time required:
to execute one cycle of the total program.
