TPC 298 Programmable Logic Controllers Flashcards
The time it takes a programmable controller to run through its program and return to the beginning is called
scan time
The two circuits in an electromagnetic relay are the control circuit and the _______ circuit.
power
Another term for a PLCs firmware is its
operating system
The binary system is based on the number ________. The hexadecimal system is commonly used with PLCs is based on the number ______.
2; 16
The Boolean NOT function acts as an
inverter
Ladder logic differs from most other computer languages in that it is
drawn graphically
In ladder logic, the output instruction that looks like a coil is called
output energize
In the binary system, each bit has a weight of ______ times the digit to the right of it
two
Which of the following number systems uses both letters and number symbols
HEX
Which device creates a numerically coded binary signal to represent an output condition?
Encoder
The final step of a PLC scan involves
writing the output image table
In Boolean programming, all logic is some combination of which operations?
AND, NOT, OR
In ladder logic programming, a ________ symbol is used for input instructions, and a _______ symbol is used for output instructions
contact; coil
What is the purpose of a rung comment?
Explain a program operation
When a ladder logic program is written as part of a larger program a ______ is used to tell it when to start its sequence
handshaking signal
In most PLC applications, each pushbutton contact is wired to an
input terminal on an input module
Which output device is sometimes used as a repeater, using a signal to control several different loads?
Relay
If an I/O module supplies current, it is considered a ______ module
sourcing
To be useful to a PLC, analog input signals must be _____ by an input module
digitized
The temperature range a thermocouple can detect is determined by the
combination of metals used
Which type of signal does an incremental encoder generate?
chain of pulses
The number of TTL output devices a TTL output modules can drive is called
fanout
When sizing a programmable controller system, you must consider I/O, memory, and
scan time
The first step in developing a PLC system to meet given specifications is
sizing the system
A bill of material should include a complete list of part numbers, device numbers cross-referenced in the drawing, and the _______ of each part.
manufacturers
Which of the following documents walks you through the complete PLC system operation?
Sequence of operation
The most important tool a maintenance technician can possess is a
documentation package
Information concerning parts replacements, adjustments, and other system changes can be found in the
maintenance log
As a good general rule, you should replace the battery in a programmable controller
annually
Once you understand how a PLC system works, the next step in troubleshooting it is to
gather information
Which of the following is the most common cause of a program problem
changes made to the original program
Most hardware problems in a PLC system occur in the
I/O devices
Which of the following is a recommended test strategy for troubleshooting?
start at the switch and test each connection until you reach the controller
Which of the following transmission media has the highest data rate?
Fiber Optic cable
Which type of data transmission uses single frequency?
baseband
