MET 284
Use ANSI/NFPA 70-1999 Wire Current Ratings to determine the appropriate wire (by AWG #) to safely used to carry a load current of 8A.
16 AWG
Determine the number of bits used to represent a ULINT using the Micro850 PLC
64
DeviceNet is ________.
A low-cost communications single cable network with input and output devices with an embedded microprocessor for network communications
Which one of the following scan statements is NOT true?
A one second scan time is common.
Input instructions D and E are in the ________ configuration.
AND
Current flows into the ________.
All of the above
Which of the following statements best describes electronic timing relays?
All of the above
Which of the following statements about a single pole double throw relay is true?
All of the above.
What is the appropriate tag for a flow meter that compares the difference in flow between two pipes and transmits the information to a controller using a standardized scale.
FDIT
A control system can eliminate all output error.
False
An output coil instruction can be energized if the input condition in its rung does not provide a path for logic continuity.
False
PLC outputs in lab are permanently configured as sourcing.
False
On a ControlLogix system the processor is placed in:
Any slot.
The PLC used in lab has 48 IO points.
False
The SUS command and the HALT command have the same functionality.
False
Which NEMA motor class has the worst efficiency?
Class D
Block diagrams of PLC controlled systems are ________.
Complex systems that are represented by a series of simple rectangles
What one item in the output module circuit below should be changed to make it correct?
Current flow direction
The +24VDC and -24VDC terminals are separated by 24VDC.
True
The most commonly use PLC programming language is:
Vendor ladder logic.
The most commonly use PLC programming language used in the United States is:
Vendor ladder logic.
What logic gate is represented by the combinational logic circuit pictured.
XNOR
Which logic gate outputs a HIGH when both inputs are at different logic levels?
XOR
The memory size of a double word is ________.
Four bytes
Which of the following is NOT a correct step in the placement of troubleshooting brackets?
Generally, the right brackets are placed on the left side of output blocks that are not operating.
PLC solid-state outputs are not available in the ________.
High current mode
Identify the true statement for this timer circuit 40 seconds after the NO momentary push button switch connected to terminal 1 in module 1 is pressed and released.
I:1/1 is false.
Which of the following standards deals with the naming (tagging) of devices in a process control loop
ISA-5.1
Which one of the following statements for the Logix PLC tag addressing is true?
Input and output tag names must be assigned to an input and output terminal before program can be executed.
What one item in the input module circuit below should be changed to make it correct?
Input module should be sinking
Which of the following is NOT normally present on both the PLCs and PCs?
Input modules
A switch pole is the ________ moved by the switching mechanism.
Internal conductor
Which of the following statements about a single pole double throw relay is NOT true?
It has a center off position.
Which of the following statements is not correct?
It is usually safe to make direct contact with victim receiving a shock as you remove the victim from the shock source.
Which is not a contactor function?
Its contacts remain open and/or closed even after power has been removed from the coil
What combination of input instructions is needed for the output Y to be TRUE?
K and H true and F false
Address-based input and output addressing system is used in Allen-Bradley ________ systems
PLC 5 and SLC 500
Which of the following statements is NOT correct?
PLCs are not as reliable as electromechanical relays in RLL.
Which of the following RLL applications is not normally performed in early automation systems?
Proportional control of field devices
The order of operation for a program scan is ________.
Read inputs; update input register; check ladder input logic; update output register; update outputs
A packing arm must be precisely located at multiple positions in a box assembly operation. What device is responsible for coordinating position sensor data and motor power/control?
Servo Drive
Which type of relay will always maintain its operating state if power has been removed.
set/reset relays
Which type of relay is designed for turning motors on and off?
contactors
Which type of relay operates using adjustable timing?
timed relays
Internal output coils are used in which of the following situations?
to control output field devices in situations where there are a limited number of output terminals available
The NAND logic function of a relay ladder circuit is performed by _____.
two or more N.C. push buttons connected in parallel
The NOR logic function of a relay ladder circuit is performed by __
two or more N.C. push buttons connected in series
The OR logic function of a relay ladder circuit is performed by _____.
two or more N.O. push buttons connected in parallel
The AND logic function of a relay ladder circuit is performed by _____.
two or more N.O. push buttons connected in series
Determine the decimal value of 1010 0000 when stored as a SINT
# < -75
Use ANSI/NFPA 70-1999 Wire Current Ratings to determine the appropriate wire (by AWG #) to safely used to carry a load current of 16A.
#12 AWG
Use ANSI/NFPA 70-1999 Wire Current Ratings to determine the appropriate wire (by AWG #) to safely used to carry a load current of 12A.
#14 AWG
Use ANSI/NFPA 70-1999 Wire Current Ratings to determine the appropriate wire (by AWG #) to safely used to carry a load current of 6A.
#18 AWG
The horizontal lines of a ladder diagram are referred to as __________.
) rungs
Determine the number of bits used to represent a DINT using the Micro850 PLC.
32
Determine the number of poles in a synchronous motor deployed in the US with a speed rating of 1800 RPM.
4
Determine the maximum value that can be stored using a UDINT variable on the Micro850.
4294967295
Determine the maximum value that can be stored using an UINT variable on the Micro850.
65535
Determine the number of bits used to represent an SINT using the Micro850 PLC.
8
What is the maximum numbers of digital outputs that can be used on the base version of the lab PLC (2080-LC50-24QWB).
9 to 11
AC output field devices can interface to ________.
AC output modules Relay output modules
Input instructions H, F, D and E are in the ________ configuration.
AND/OR
Which of the following is not normally found on a PLC?
All of the above
PLC control applications could be which of the following:
All of the above.
PLC control applications could be:
All of the above.
Which of the following is NOT a correct statement when troubleshooting timer ladder logic?
Most difficult ladder timer programs to test have linked or cascaded timers, large PRE values, and very slow execution times.
Select the timing relay that fits this operation: after the coil is energized the NO contacts close and remain closed as long as the coil is energized. When the coil is de-energized, the NO contacts remain close for the set time delay value.
NOTO
On SLC 500 models the processor is placed in:
Next to the power supply.
An SLC 500 output address is O:2/10, what slot is the module in and what terminal is used for the connection?
None of the above
SLC 500 ladder logic with two cascaded timers ________.
None of the above
Identify the true statement for this timer circuit 35 seconds after the NO selector switch connected to terminal 1 in module 1 is turned on.
None of the above.
Which one of the following statements on Logix addressing are NOT true?
The maximum tag name length is 50 characters.
Which one of the following files is NOT a file structure used by the SLC 500?
Sequencer (file 2)
Which of the following is not a limit switch?
Standard selector switch
Identify the true statement for this timer circuit 15 seconds after the NO momentary push button switch connected to terminal 1 in module 1 is pressed and released.
TT is true.
Which of the following parameters is NOT used by the PLC 5 and SLC 500 timer instructions?
Trigger voltage
Open loop control systems expect that the inputs and the process will always be the same with no deviation.
True
Open loop control systems expect that the inputs and the process will vary with some deviation.
True
The first step of implementing a PLC into a controls environment is identifying the input and output devices within the environment.
True
The lab PLC can be used to control outputs from 0-24VDC and from 0-24VAC
True
The lab PLC will respond to a 24VDC or 24VAC signal on its inputs.
True
The sum of sourcing terminals minus the sum of sinking terminals in a closed current loop always equals zero.
True
Which of the following can be used to directly control and vary the speed of a three-phase induction motor?
Variable Frequency Drive
The two vertical lines of a ladder diagram are referred to as __________.
rails
PLCs are ________ designed for use in the control of a wide variety of manufacturing machines and systems.
special-purpose industrial computers
Which of the following is true?
Current flow from the field device must flow into the current sinking PLC output to ground
Input instruction X is in the ________ configuration
FEEDBACK
A PLC is faster at calculation than a PC.
False
A mechanical control system is easier to modify than an electromechanical control system.
False
A single break switch is more safe applied in high voltage scenarios than a double break switch
False
An E-stop controls power to both the PLC and all field devices.
False
An activated input on an interrupt will take always take priorty over the main program.
False
Closed loop control uses positive feedback to reduce measured error.
False
The COM terminal on a PLC must always be tied to 0V for safety.
False
The first PLC every sold was the PLC5.
False
The output coil of a relay ladder diagram is capable of controlling only one contact.
False
The standard color for grounded wire in the US is black.
False
Which of the following statements is not correct?
Fibrillation is produced by even a small DC current.
The examine if closed instruction ________.
Has the following logic symbol (-| |-)
An RES used with an RTO timer ________.
Has the same address as the RTO timer
A PLC program requires a routine where 2 SINT values are multiplied. What is the smallest data type available that can accurately hold the result for all possible input cases.
INT
A PLC program requires a routine where 2 SINT values are summed. What is the smallest data type available that can accurately hold the result for all possible input cases.
INT
A PLC program requires a routine where a SINT value is subtracted from a SINT value. What is the smallest data type available that can accurately hold the full result for all possible input cases.
INT
Which of the following conditions is NOT considered when and an XIC versus an XIO input instruction is selected?
Matching the type of input contacts (NO or NC) with input instructions (XIC or XIO).
Which of the following statements is not correct?
Mechanical timing relays provide 0.05 to 180 seconds of on-delay and off-delay with an accuracy of +/- 10 percent.
The first company to build PLCs was ________.
Modicon
A TON timer rung is active and the ACC value is greater than the PRE value, so the ________ timer bits are true.
Both the EN and DN
A TON timer rung is active and the ACC value is less than the PRE value, so the ________ timer bits are true.
Both the EN and TT
A TOF timer rung is false and the ACC value is less than the PRE value, so the ________ timer bits are true.
Both the TT and DN
Which of the following statements about RLL is NOT true?
The right power rail is positive or the high side of the source, and the left power rail is the power return or ground.
Selector switches are classified as ________.
Triple break
A PAC can work as a PLC but a PLC cannot work as a PAC.
True
A PLC can operate for longer periods without a reboot than a PC.
True
Determine the decimal value of 1100 0000 when stored as a SINT
-75 < # ≤ 0
A TON timer rung is active and the ACC value is greater than the PRE value, so the ________ timer bits are true.
A TON timer rung is active and the ACC value is greater than the PRE value, so the ________ timer bits are true.
SERCOS is ________.
A digital motion control network that interfaces the motion control module in the PLC with the servo motor drive through a fiber optic cable
Which of the following is the feedback signal flow definition?
A signal flow is where part of the output signal is diverted back to the system input and added to the input signal.
Which of the following inputs will produce a HIGH output for Q=(A+B)⋅C?
ABC-
The ________ is moved toward the relay electromagnet when the relay is on.
Armature
Which of the following statements is NOT true after the start selector is true?
B3/1 output is true for 5 seconds.
On all Allen Bradley PLCs the ________ is used to deliver power and signals to the I/O modules.
Backplane
Which form of linear actuator allows for the most flexibility in controlling the position of the shaft?
Ball Screw
Which one of the following ladder output branch statements is NOT false?
ControlLogix processor requires that multiple outputs are in series and does not allow parallel single output per branches.
PLCs are
Designed to work in harsh industrial environments.
Which of the following statements is not correct?
Each rung of the ladder logic represents a logical statement executed in software — inputs on the right and outputs on the left.
Which of the following statements is NOT true?
If a mechanically operated industrial switch is used the trigger point can not be changed.
Which of the following is NOT a correct step in the replacement of RLL with PLC ladder logic?
In an on-delay conversion, replace the NO timed contact with an XIC instruction addressed with the done bit of the PLC timer. In an off-delay conversion, replace the NO timed contact with an XIO instruction addressed with the done bit of the PLC timer.
A float switch is also known as a _______
Level switch
Through-beam sensors provide the ________.
Longest sensing distances
Which is NOT a feature of a horn?
Muting capability
Select the timing relay that fits this operation: after the coil is energized NC contacts open and remain open as long as the coil is energized. When the coil is de-energized, the timed contacts remain open for the set time delay value.
NCTC
Select the timing relay that fits this operation: after the coil is energized the NC contacts remain closed until after the time delay value.
NCTO
Select the timing relay that fits this operation: after the coil is energized, the NO contacts remain open for the time delay value and then close after the time delay.
NOTC
Identify the true statement for this timer circuit 25 seconds after the NO selector switch connected to terminal 3 in module 6 is turned off.
O:2/1 is true.
Identify the true statement for this timer circuit 25 seconds after the NO selector switch connected to terminal 1 in module 1 is turned
O:3/0 is false.
Identify the true statement for this timer circuit 25 seconds after the NO selector switch connected to terminal 1 in module 1 is turned on.
O:3/0 is false.
An RTO timer rung is false and the ACC value is greater than the PRE value, so the ________ timer bits are true.
Only the DN
A target entering the magnetic field of the inductive sensor causes the ________.
Oscillation amplitude to drop
PLC relay output modules are used for ________.
Power isolation for each of the field devices interfaced
A swimming pool heater uses a heating element (on/off) to heat water to a desired temperature to counteract changes the pool water temperature due to changes in ambient temperature of the surrounding environment. The water is circulated by a single centrifugal speed pump which is always active regardless of the on/off state of the heater. Water temperature is measured by a single device which contains a sensor and all circuitry to output at standardized value. Match the device with the appropriate term.
Set Point (SP) - desired water temperature Manipulated Variable (MV) -pool water Final Control Element (FCE) - water heater Process Value (PV) - current water temperature Control Output (CO) - heater on/off signal
Which of the following statements on multifunction timing relays is NOT true?
Since they are electronic they are part of the PLC.
Pressure switches open or close based on the pressure applied to the device by all the items, but one. Which one?
Solids
The status operation for the SLC 500 ________.
Stores data related to the operation of the processor in specific memory locations in file 2
Which of the following statements is NOT true after the start selector is true for 10 seconds?
T4:2 sets the off time for the output pulse to 4 seconds.
Capacitive sensors are more sensitive than inductive sensors to changes in ________.
Temperature Humidity
The ________ instruction is useful for troubleshooting timer ladder logic.
Temporary end
Which of the following steps is not a correct part of the empirical program development process?
Test all input and output devices to verify correct operation.
Which of the following statements is NOT correct?
The cost and size of PLCs have increased significantly in the last 10 years.
In a current sinking DC input module ________.
The current flows out of the input field device
In the process of developing a PLC program, the developer can always change ________ to work with the other given conditions of the system.
The input (XIC or XIO) and output (OTE, OTL, or OUT) instructions.
In through-beam sensors, ________.
The light source and receiver are in separate housings
Which of the following statements is not correct?
The victim usually releases the electrical conductor when energy is removed.
When a relay is NOT energized:
There is an electrical path through the NC contacts.
Identify the true statement for this timer circuit 40 seconds after the NO momentary selector switch is turned on and off.
Timer_30_sec.DN is off.
Solenoid valves are used as a pilot valve to control the flow ________
To a pneumatic-actuated valve
A switch throw is one of ________.
Two or more positions that a switch can take
The inputs of the PLC used in lab (2080-LC50-24QWB) can configured as ____________.
all of the above
The outputs of the PLC used in lab (2080-LC50-24QWB) can configured as ____________.
all of the above
Determine the maximum value that can be stored using a ULINT variable on the Micro850.
1.84467E+19
What is the maximum numbers of digital inputs that can be used on the base version of the lab PLC (2080-LC50-24QWB).
12 to 14
Determine the decimal value of 0001 1000 when stored as a SINT
0 < # ≤ 75
Determine the decimal value of 0100 1000 when stored as a SINT
0 < # ≤ 75
EitherNetI/P is ________.
An open industrial networking standard that takes advantage of commercial off-the-shelf Ethernet hardware
ControlNet is ________.
An open network standard that uses the producer/consumer network model to efficiently exchange time-critical application information in control systems
The scan time ________.
Determines how fast an output actuator will respond after a change in an input filed device
The PLC was invented by ________.
Dick Morley
Power for the field devices typically comes from ________.
Isolated factory floor voltage sources
Which one of the following address elements is not used for the physical address of a Logix tag?
Rack: Rack is the rack number where the process is located.
Identify the true statement for this timer circuit when the pump contactor is cycled on and off for the following time sequences: 100, 300, 25, 900, and 75 seconds.
The ACC is 1400.
An RTO timer rung is true and the reset instruction rung for the timer is true, so
The ACC is reset to zero, the DN bit is false, and the EN bit is true.
Which one of the following statements about the Allen-Bradley PLC memory structures and addressing is NOT true?
The Logix system permits either rack/slot- or tag-based addressing.
Which of the following statements is true?
The accumulator decrements by the time base value when the timer instruction is false.
Which of the following statements is NOT correct?
The accuracy of PLC timers can be affected by short scan time.
Observation of the system indicates that the NC high level float switch is not active but the pump motor is not running. All power sources are present. A check of the output module indicates that O:2/2 output indicator is off. How will the brackets move?
The right bracket moves to the output of the Output Module.
Which of the following is NOT verified in the troubleshooting of relays?
The settings are correct.
Which of the following is NOT verified in the troubleshooting of switches?
The switching distance is correct.
Which one of the following statements on tags in the Tags Window Dialog Box is NOT true?
The tag name and tag data type must be identified and entered before the program ladder logic is created.
Which of the following statements for the PLC 5 and SLC 500 timer addressing is NOT true?
The timer number range is 0 to 255 and is separated from the file number by a forward slash (/).
Which of the following statements for the Logix timer addressing is NOT true?
The timer tag name must have the word timer included.
In the ladder below, the valve on push button is a NO momentary switch and Valve off push button is a NC momentary switch. Which statement below is true?
The valve solenoid is on after the Valve on switch is pressed and released and is turned off when the Valve off switch is pressing.
Which of the following is NOT true?
When troubleshooting sensors, the state of the contacts can be manually changed.
