ECE 455 Test 1- Quiz
(a) _______ and (b)________ are the basic symbols of the ladder logic program instruction set.
(a) coils, (b) contacts
in general, a ladder logic rung consists of input conditions represented by (a) _______ symbol and an output instruction represented by the (b) _______ symbol.
(a) contact, (b) coils
Scan patterns are identified as being either (a) ______ or (b) ______
(a) horizontal, (b) vertical
The memory space can be divided into the two broad categories of (a) _______ files and (b)_______ files
(a) program (b) data
The address I:1/4 breaks down into the following parts: I is for (a) _____. the colon is used to separate the module type from the (b)______. One is (c)_______ number. the forward slash is used to separate the slot from the (d)______. Four is the (e) _______ number.
(a)input,(b)Slot, (c)Slot, (d)terminal, (e) terminal
Allen-Bradley PLC have two different memory structures identified by the terms (a)_____-base and (b) ____-based systems
(a)rack, (b).tag
Fiber optic sensors
Are not affected by electrical interference, carry light wave signals, use flexible cable containing tiny fibers
Parallel connections of a ladder logic are typically called?
Branches
The actual scan time is:
Calculated and store in the PLC memory, computed each time the END instruction is executed, the time taken to scan inputs and outputs and execute the user program
if a PLC has a total scan time of 10 ms and has to monitor a signal that _______ , then the controller may not detect this change
Change state twice in 5 ms
In the ladder logic program, output are represented by ?
Coil Symbols
When a program rung consists of an output instruction only, the output would be
Continuously ON
Bar code scanners are used primarily for
Data collection
An electromagnet control relay is basically a(n)
Electromagnet used to switch contacts
All PLC manufacturer organize their memories in the same way. (TRUE OR FALSE)
False
The addressing formats for inputs and outputs is standard for all PLC models. (TRUE OR FALSE)
False
The greater the scan time, the faster the PLC can react to changes in inputs. (TRUE OR FALSE)
False
When the XIC instruction is associated with a physical input, the instruction will be set to 1 when there is no input voltage applied to the terminal. (TRUE OR FALSE)
False
each individual contact instruction can be used only once throughout the program. (TRUE OR FALSE)
False
it takes the processor exactly the same amount of time to examine different types of instructions. (TRUE OR FALSE)
False
Which of the following standard PLC programming languages is a graphical language?
Function Block diagram, Sequential Function Chart, Ladder diagram
A(n) _______________ scan pattern examines instructions rung by rung
Horizontal
The two types of patterns used to accomplish the scan function are _____________
Horizontal and vertical
The Status Bit of Switches and pushbuttons connected to a PLC are stored in the _________
Input Image table file
The light source used in most industrial photoelectric sensors is a(n)
LED
Which of the following is a factor in determining the total scan time?
Length of the ladder program, type of instructions executed, speed of the processor
if the program calls for a specific output to be on, the corresponding bit in the output image file is set to _______.
One
The output data are sent to the __________
Output field devices
The abbreviation NO (Normally open) and NC (Normally closed) represent the electrical state of switch contacts when
Power is not applied
A thermocouple, when heated
Produces a small DC voltage.
Most of the total PLC memory is used for the _________
Program
The memory organization of a PLC can be divided into what two broad categories?
Program and Data Files
The Scan is normally a sequentially process of _____
Reading the status of inputs, evaluating the control logic, and energizing or de-energizing the outputs
A(n) __________ converts light energy directly into electric energy
Solar cell
Define Status
Stores Controller operation information
When the PLC is required to operate the user program without energizing any outputs, it is placed in the ___ mode?
TEST
Both normally open and normally closed pushbuttons can be examined for a XIC or XIO condition. (TRUE OR FALSE)
True
Misunderstanding the way the PLC scans a program can cause programming bugs. (TRUE OR FALSE)
True
Most instructions require one word of memory. (TRUE OR FALSE)
True
On some PLC models, branches can be established at both the input and output portions of a rung. (TRUE OR FALSE)
True
Scan time caries with program content and length.(TRUE OR FALSE)
True
The memory organization of a PLC is often called a memory map. (TRUE OR FALSE)
True
The rung condition and OTE instruction are false if no logical continuity path has been established. (TRUE OR FALSE)
True
The status of the OTE instruction is set to 1 to energize the output and to 0 to de-energize the output. (TRUE OR FALSE)
True
The user program contains the logic that controls the machine operation. (TRUE OR FALSE)
True
There may be a limit to the number of series contact instructions that can be included in one rung of ladder logic program/ (TRUE OR FALSE)
True
When the XIO instruction is associated with a physical input the instruction will set to 1 when there is no input voltage applied to the terminal. (TRUE OR FALSE)
True
When there is a true logic rung path, all parallel output in the rung become true. (TRUE OR FALSE)
True
an internal output does not directly control an output field device. (TRUE OR FALSE)
True
if any input signal changed state very quickly, it is possible that the controller may never be able to detect the change.(TRUE OR FALSE)
True
the status of input and output devices is stored in a data table. (TRUE OR FALSE)
True
The output energize instruction:
is also known as the OTE instruction, signals the PLC to energize or deenergize the output, looks and operates like relay coil
The Examine if Open instruction
is also known as the examine-off instruction, is also known as the XIO instruction, looks and operates like a normally closed relay contact
The examine if closed instruction:
is also known as the examine-on induction, is also known as the XIC instruction, looks and operates like a normally open relay contact
A contactor
is designed to handle heavy power loads.
The maximum number of rungs allowed is
limited only by the memory size
an inductive proximity sensor is actuated by
metal object
A(n) _______ branch starts or ends within another branch
nested
The maximum number of output allowed per rung
one
the address I:1/3 identifies an input module residing in slot ___ of the PLC chassis
one
Branch instructions are used to create ____ paths of input conditions
parallel
Branch input instructions are used to create a:
parallel path of input instructions
The force applied to stain gauge causes it to bend and change its ______
resistance
Each Complete horizontal line of ladder diagram is generally referred to as a(n)
rung
The program ______ cycle is a continuous and sequential process of reading the status of inputs, evaluating the control logic and updating the output
scan
A tachometer normally refers to a(n) _______ used for speed measurement
small generator
The ladder logic program language is basically a(n) ____ set of instructions used to create the controller program
symbolic
A normally open limit switch is wired to an input module and programmed using XIO instruction. the instruction will be true when?
the limit switch is open
A(n) _______ operates by sending sound waves towards a target and measuring the item it takes for the pulses to bounce back
ultrasonic sensor
Define bit
used for internal relay logic storage
Define Input
used for storage of the status of input field devices
Define Integer
used to store numeric values
Most proximity switches come equipped with an LED status indicator to
verify the output switching action
A programmed XIC instruction
with a bit status of 1 will have logic continuity
A programmed XIO instruction
with a bit status of 1 will not have logic continuity, is examined for an OFF condition
A proximity switch can be actuated
without any physical contact.
when logic ____ exists in at least one path, the rung condition is said to be true
continuity
an encoder is used to
convert motion into digital signal
Internal control relay
does not directly control an output field device
an internal output is used when an output instruction is required but no connection to a(n) _______ is required.
field device
The maximum number of series contacts allowed per rung is
five
The address O:3/7 would be found on terminal ___ of an output module residing in slot ___ of PLC chassis
7,3
Define Timer
Used for storage of accumulated and preset values
Define Output
Used of the storage of the status of the output field devices
Define Program
Used to enter the user program
Define Run
Used to execute the user program
Define Test
Used to monitor the user program without energizing any outputs
The __________ Will account for most of the total memory of a given PLC system
User Program
The _______ instruction always interprets as I status as true and 0 status as false
XIC
When using an XIC instruction, the reference address could be?
a bit of from an input device, a bit from an internal relay, a bit from an output device
The most common actuator for a reed switch is
a permanent or electromagnet
The addressing format used with PLCs
indicates what PLC input is connected to what input device and indicates what PLC output is connected to what output device.
The _____ image table file is updating during the I/O scan to reflect the current status of digital inputs
input
the main function of the ladder logic program is to control output based on ________ conditions.
input
The ____ will indicate what PLC input is connected to what input device and what PLC output will drive what output device.
address
Capacitor proximity sensors:
are actuated by both conductive and nonconductive materials
A ladder rung is said to have logic continuity when
as least one left to right true logical path exists
if a switch connected to an input module is closed, a binary 1 is stored in the proper _________ location
bit
The last element to be entered on a ladder rung is a(n)?
coil
A limit switch is usually actuated by
contact with an object
