Download PLC Final Revision Test: Comprehensive Questions and Answers and more Exams Computer Science in PDF only on Docsity!
Questions.
The processor's _______ and ______ indicators should be solid green if it is operating correctly and in run mode. - Correct Answer: >>RUN, OK The most common of PLC system failures are: - Correct Answer: >>Wiring and input devices When troubleshooting a PLC control system, the first step should be? *** - Correct Answer: >>Identifying the faulty operation ___________ descriptions are used to describe the tag/instruction combinations in ladder logic. - Correct Answer: >>Main operand When troubleshooting, observing that all input I/O state indicators are off (but processor indicators are on) means that _____________ to the input and output devices has been lost. - Correct Answer: >>Control power The first step in troubleshooting the ControlLogix chassis power supply is to verify that the power supply is __________. - Correct Answer: >>On Processor module indicators include ________, _________, ________, and ________ - Correct Answer: >>Run, Force, SD, OK
Questions.
To enable forces, click the Forces drop-list on the online toolbar and select the I/O Forcing option, then the _________________ option. - Correct Answer:
Enable all I/O forces A(n) _____________ is a name, property, parameter, or value for the device for which the object data applies. - Correct Answer: >>Attribute The ____________ of I/O chassis contains a circuit board that provides the path through which modules communicate and the DC power is supplied to all modules. - Correct Answer: >>Backplane When troubleshooting, observing that all PLC indicators are off could be caused by a(n) _______________ or a bad chassis power supply. - Correct Answer: Complete power failure ________________ is the process of finding the cause or fault of a machine malfunction. - Correct Answer: >>Troubleshooting __________ description is used to describe the routine and its operation. - Correct Answer: >>Routine Mechanical input devices, such as pushbuttons and limit switches, can be tested out-of-circuit using a(n) ___________ test. - Correct Answer: >>Continuity
Questions.
The PLC requires that AC power be supplied from an external source to its chassis ___________. - Correct Answer: >>Power supply In the case of outputs, the Force On function is used to turn an output device ______, regardless of program or processor logic. - Correct Answer: >>On PLC troubleshooters should use a(n) _____________ approach to isolate the cause of the problem. - Correct Answer: >>Methodical Troubleshooting a ControlLogix processor requires using the processor's _________ indicators to determine the operating condition of the processor. - Correct Answer: >>Status The ControlLogix family of programmable controllers has a test mode that enables the user to test program operation without energizing ____________. - Correct Answer: >>Outputs Because downtime is so expensive, most troubleshooters in manufacturing environments perform _________ level troubleshooting only. - Correct Answer: >>System After identifying the problem (or symptom), the next step is to check the ____________. - Correct Answer: >>Status indicators
Questions.
__________ are data structures used to store status and identifying data about the controller and its operation, hardware, and program. - Correct Answer:
Objects The controller module's _________ indicator flashes amber when forced I/O conditions appear in the user program and appears solid amber when those conditions are enabled. - Correct Answer: >>Force The ________ module, being an industrially hardened computer, is susceptible to hardware failures just like any other computer. - Correct Answer: Processor If an output device doesn't work even though the corresponding output terminals are energized, the problem is either in the ____________ or interface wiring. - Correct Answer: >>Device A(n) ____________ is a graphical method of troubleshooting that uses block symbols connected by flow lines to show the sequence of steps to follow. - Correct Answer: >>Flowchart ________________ is the user text associated with the rungs and instructions of a controller project that explains the operation of that item. - Correct Answer: Project documentation
Questions.
In a single-cycle program, the start and stop inputs ________ control the output. - Correct Answer: >>Directly In the ___________ cycle program, the start and stop pushbuttons, PB1 and PB2, control an internal coil instruction that controls the start and stop of the sequence. - Correct Answer: >>Continuous The drill cylinder is controlled with a(n) ______ solenoid valve. - Correct Answer: >>Single The reason that different valves are used for the clamp and drill cylinders is __________. - Correct Answer: >>Safety The specific order in which automatic machines perform actions is called a(n) ___________. - Correct Answer: >>Sequence An example of a PLC program that performs an event-driven sequence is a(n) ___________ cylinder program. - Correct Answer: >>Reciprocating The __________ function causes the machine to stop after the machine finishes the last step in its cycle. - Correct Answer: >>Cycle stop
Questions.
Most _________ machines are designed with more than one type of stop function to meet various situations where a machine should be stopped. - Correct Answer: >>Automatic Some applications that use _________ are motors, production, alarms, and welding. - Correct Answer: >>Counters A few applications that use _______ functions include energy management, mixing operations, dwell functions, communication, queueing, and alarms. - Correct Answer: >>timed _______ instructions are used to activate or deactivate devices after a predefined number of cycles. - Correct Answer: >>Counter A(n) ____________ is a detailed sequence that shows the on/off status of every input and output device/address for each step in the sequence. - Correct Answer: >>Truth table _______ instructions are used to activate or deactivate a device after a predefined time. - Correct Answer: >>timer After _______ and _______, timers and counters are the most commonly used PLC instructions. - Correct Answer: >>Coils, contacts
Questions.
The advantage of a JMP instruction is that is reduces processor ________ time. - Correct Answer: >>Scan An MCR is used as a safety device to remove power from all PLC outputs to disable all _________. - Correct Answer: >> The JSR instruction is a program control instruction that causes the processor to run a(n) ___________. - Correct Answer: >>Subroutine ___________ a PLC program puts all outputs in startup state and checks inputs to verity that the process can safely be restarted. - Correct Answer:
Initializing The First Scan Flag is often used in applications to __________ a program to a known state on power-up of the controller. - Correct Answer: >>Initialize When a JSR instruction is de-energized, all outputs in the subroutine remain in their __________. - Correct Answer: >>Last state A subroutine is a program which can be executed by another ____________ - Correct Answer: >>Routine
Questions.
The LBL instruction must always be the ________ instruction in the rung. - Correct Answer: >>First When the ______ instruction is energized, all program logic between it and the LBL instruction is frozen in its last state. - Correct Answer: >>JMP The Minor Fault Flag is set when a program ________ causes a minor fault to occur. - Correct Answer: >>Error The Accumulated (ACC) value of an Up/Down counter is equal to the number of up counts _______ the number of down counts. - Correct Answer:
MINUS Tag property local refers to module defined because tags are first defined in the - Correct Answer: >>I/O module serial comm is best described by - Correct Answer: >>connecting RS- 232 cable (null Modem) between devices baud rate is how quickly data is - Correct Answer: >>exchanged input images are the type of memory file used to addressed hardwired - Correct Answer: >>inputs
Questions.
____ discrete output modules use a transistor as a switching device - Correct Answer: >>DC Triac is for - Correct Answer: >>AC transistor is for - Correct Answer: >>DC Logics are - - Correct Answer: >>AND, OR, NOT, NOR, NAND counters - Correct Answer: >>count up, count down, latch, unlatch routines - Correct Answer: >>applications intructions, inputs, outputs. subroutines - allow for several programs on a single plc routine programs, - Correct Answer: >>tasks. are an example of plc programming language projects. Bits are - Correct Answer: >>integers double intergers (DINT) word boolean 5 commonly used numbering systems are - Correct Answer:
hexadecimal, decimal binary octal binary coded decimal (BCD)
Questions.
weighted value - Correct Answer: >>LSD (least, furthest to the right) MFD(most, furthest to the left) a plc output is wired to a motor starter, N.O auxiallary contact from the motor starter is an input to the plc. if the output of the plc is off then the input to the plc will be what? - Correct Answer: >>off numbering systems used to display timing or counter numbers are in a - Correct Answer: >>decimal base NPN device is one that can switch the negative side of the circuit while a PNP device switches the - Correct Answer: >>positive side. NPN schematic symbol points down, while PNP - Correct Answer: >>UP and in RTO - Correct Answer: >>Retentive Timer On NON Retentive - Correct Answer: >>Timer ON (TON) Timer off (TOF)
Questions.
Main us of an I/O diagram is to document the physical connections of the PLC to the machine - Correct Answer: >>electrical hardware. Active low input module: Current sinking input module must be used with a - Correct Answer: >>current sourcing sensor 5 features of output modules; ss dc output modules use transistors for - Correct Answer: >>switches You want to look at voltage required of the load device, current draw of the load device and - Correct Answer: >>number of inputs required. the purpose of a digital output module is to energize loads in response to plc - Correct Answer: >>instruction a diode cannot be used with an AC control - Correct Answer: >>voltage the best place to start when trouble shooting an issue with a PLC system is to identify the symptoms of a - Correct Answer: >>specific problem 7 types of PLC faults : the first you should verify when there is a processor fault is to check the processor fault messages on - Correct Answer: >>Error codes
Questions.
at the start of an individual start up when trouble shooting a suspected PLC power supply problem and the input AC voltage to a PLC is good - Correct Answer:
the power supply fuse and the input voltage selection jumper should be checked.
Retentive Timer On NON Retentive - Correct Answer: >>Timer ON (TON) Timer off (TOF) ## Questions. Main us of an I/O diagram is to document the physical connections of the PLC to the machine - Correct Answer: >>electrical hardware. Active low input module: Current sinking input module must be used with a - Correct Answer: >>current sourcing sensor 5 features of output modules; ss dc output modules use transistors for - Correct Answer: >>switches You want to look at voltage required of the load device, current draw of the load device and - Correct Answer: >>number of inputs required. the purpose of a digital output module is to energize loads in response to plc - Correct Answer: >>instruction a diode cannot be used with an AC control - Correct Answer: >>voltage the best place to start when trouble shooting an issue with a PLC system is to identify the symptoms of a - Correct Answer: >>specific problem 7 types of PLC faults : the first you should verify when there is a processor fault is to check the processor fault messages on - Correct Answer: >>Error codes ## Questions. at the start of an individual start up when trouble shooting a suspected PLC power supply problem and the input AC voltage to a PLC is good - Correct Answer: >>the power supply fuse and the input voltage selection jumper should be checked. To verify that an output is sending the correct signal to a relay from the PLC output module you should - Correct Answer: >>use a voltmeter to verify the correct voltage to the relay wiring a field device causes the majority of PLC system - Correct Answer: failures indicator lights on a plc are used for - Correct Answer: >>diagnostics & maintenance PLC input lights are off, but if they are on it could be a - Correct Answer: faulty wiring , a defective sensor, or a faulty power supply you will not find provisions for human intervention beyond e-stop in the code of - Correct Answer: >>automatic program
Questions.
you should document the program after altering it to do an additional task by date, - Correct Answer: >>the intended effect, & which line of the program you changed a major difference between manual mode and an automatic mode of a plc controlled machine is the logic uses - Correct Answer: >>different inputs for the operator the following happens to the information of a sequencer as it advances through its steps it transfers from the - Correct Answer: >>outputs module to the input module retentive timer reset is necessary to - Correct Answer: >>clear out accumulated value timers time intervals and counters - Correct Answer: >>count events a wireless connection is not critical for - Correct Answer: >>online editing online editing relies on an active serial communication between devices, which best - Correct Answer: >>describes the difference between online & offline program editing
Questions.
the remote function of a plc allows the user to - Correct Answer:
perform the plc operations status to be changed on line. A(n) _________ display is an output device that enables a machine operator to view the Accumulated or Preset value of an instruction without the use of a programming terminal. - Correct Answer: >>LED The rate at which data is sent over a serial line in units of bps - Correct Answer: >>BAUD Most electronic sensors use a _____________ output to send a signal to the PLC. - Correct Answer: >>TRANSISTOR A ____ is an example of an actuator that could be controlled by a discrete output from a PLC. - Correct Answer: >>MOTOR STARTER One function of a PLC input interface module is to: - Correct Answer: accept signals from field devices and convert them into signals that can be used by the processor. A current sinking input module must be used with _____________? - Correct Answer: >>Current sourcing sensor
