PLC: Chapter 1-2 Test Questions with
Solved Solutions.
What is a PLC - Answer Specialized computer used to control machines
4 tasks in addition to relay switching PLCs are good for - Answer Counting, calculating,
comparing and processing of analog signals
List 6 distinct advantages that PLCs offer over conventional relay-based control systems - Answer
-Increased Reliability
-More Flexibility
-lower cost
-communications Capability
-faster response time
-easier to troubleshoot
explain the differences between open and proprietary PLC architecture - Answer an open
architecture design allows the system to be connected easily to devices and programs made by
other manufacturers. a proprietary architecture makes it more difficult to connect to another
manufacturer's system
state two ways in which I/O modules connect to the processor in a modular-type PLC
configuration - Answer Fixed and Modular configurations
Describe how the I/O modules connect to the processor in a modular-type PLC configuration -
Answer The I/O modules plug into a rack, communicate through the back plane
Explain the main function of the CPU - Answer accepts input data, executes user program,
sends appropriate outputs
function of I/O modules - Answer forms the interface by with the field devices are connected
to the controller
Function of programming device - Answer used to enter the desired program into the
processor
Function of power supply module - Answer supplies dc power to the other modules
, what are the two most common types of programming devices - Answer Laptops and
Desktops
explain 'program' as it applys to PLCs - Answer a program is a user created set of instructions
that tells the PLC to execute actions
explain 'program language' as it apply's to PLCs - Answer creates a set of rules for combining
the instructions so that they produce the desired actions
What is the standard program language for PLCs - Answer Relay Ladder Logic (RLL)
PLCs work in real time, what does this mean - Answer when something happens in the field
will result in an output
explain how the process control operation is changed by PLCs as opposed to relay based
systems - Answer Relay systems are changed by changing the wiring, PLCs are changed by
changing the program
Compare PLCs to to PCs - Answer -PLCs come with its program language built in
-PLCs are designed to handle harsher environments
-PLCs are programmed in RLL or other easily learned languages
-PLCs execute a single program in a sequential order
What two categories of software run on PCs run as well on PLCs - Answer software that
allows a user to write and document PLC programs. software that allows the user to monitor
and control a PLC program
what is a Programable automation controller - Answer a device that combines PLC control
and ruggedness with PC functionality
List four criteria PLCs are catagorized in - Answer -functionality
-number of inputs and outputs
-cost
-physical size
compare the single ended, multi-task, and control management types of PLC applications. -
Answer single ended involves the PLC controlling one process, multi task involves multiple
processes, control management involves one PLC controlling several others
Solved Solutions.
What is a PLC - Answer Specialized computer used to control machines
4 tasks in addition to relay switching PLCs are good for - Answer Counting, calculating,
comparing and processing of analog signals
List 6 distinct advantages that PLCs offer over conventional relay-based control systems - Answer
-Increased Reliability
-More Flexibility
-lower cost
-communications Capability
-faster response time
-easier to troubleshoot
explain the differences between open and proprietary PLC architecture - Answer an open
architecture design allows the system to be connected easily to devices and programs made by
other manufacturers. a proprietary architecture makes it more difficult to connect to another
manufacturer's system
state two ways in which I/O modules connect to the processor in a modular-type PLC
configuration - Answer Fixed and Modular configurations
Describe how the I/O modules connect to the processor in a modular-type PLC configuration -
Answer The I/O modules plug into a rack, communicate through the back plane
Explain the main function of the CPU - Answer accepts input data, executes user program,
sends appropriate outputs
function of I/O modules - Answer forms the interface by with the field devices are connected
to the controller
Function of programming device - Answer used to enter the desired program into the
processor
Function of power supply module - Answer supplies dc power to the other modules
, what are the two most common types of programming devices - Answer Laptops and
Desktops
explain 'program' as it applys to PLCs - Answer a program is a user created set of instructions
that tells the PLC to execute actions
explain 'program language' as it apply's to PLCs - Answer creates a set of rules for combining
the instructions so that they produce the desired actions
What is the standard program language for PLCs - Answer Relay Ladder Logic (RLL)
PLCs work in real time, what does this mean - Answer when something happens in the field
will result in an output
explain how the process control operation is changed by PLCs as opposed to relay based
systems - Answer Relay systems are changed by changing the wiring, PLCs are changed by
changing the program
Compare PLCs to to PCs - Answer -PLCs come with its program language built in
-PLCs are designed to handle harsher environments
-PLCs are programmed in RLL or other easily learned languages
-PLCs execute a single program in a sequential order
What two categories of software run on PCs run as well on PLCs - Answer software that
allows a user to write and document PLC programs. software that allows the user to monitor
and control a PLC program
what is a Programable automation controller - Answer a device that combines PLC control
and ruggedness with PC functionality
List four criteria PLCs are catagorized in - Answer -functionality
-number of inputs and outputs
-cost
-physical size
compare the single ended, multi-task, and control management types of PLC applications. -
Answer single ended involves the PLC controlling one process, multi task involves multiple
processes, control management involves one PLC controlling several others
