Quiz 2 Flashcards
RS-485 is often referred to as a
Serial Standard
Modbus uses which of the following methods for media access
Polling
The most common form of digital communication is
Serial
The shield on Belden signal wire must grounded at
The receiver
What is the interface used with DTE’s and DCE’s
RS-232
The 8-bit extended ASCII code consists of
256 distinct combinations
The carrier protocol CSMA/CD means
Carrier Sense Multiple Access Collision Detect
An analog signal has the following characteristics
Varies in a continuous matter
Demodulation is a process that
Separates data from a carrier signal
The term that refers to communication system capable of communications in both directions but in only one direction at a time is
Half-duplex
Computer data referred to as BYTE
Is 8 bits of data
Modbus may have up to _____ slave addresses
247
The name given to hardware and software rules, as well as procedures to ensure data is transferred correctly
Protocol
Fieldbus protocol features
Digital signals using digital transmitters
RS-232 is often referred to as a
Serial standard
The correct ladder logic program for to start and stop a pump if the field hardware are NO contact type switches is
B (picture)
SCADA systems can reliably monitor and control a process only with an operator’s supervision
False
To increase the number of inputs and outputs of the PLC, once can use expansion modules
True
In gas flow calculations case, when you decrease the temperature you will see the gas flow will decrease.
False
Polling is performed when
The master requires information
Which one of the following is not a computer based leak detection monitoring system
Realflo gas meter
In RTU input, one differential pressure transmitter pressure scale is 0- 150 kPa, reading is 37.5 kPa of scale; If the flow range is 0 - 36 m3/h. this implies the flow is:
18 m3/h
Why is an uninterrupted power supply (UPS) important?
Provides uninterrupted power to mission critical devices.
Which part of message format provides the message security checks and means of denoting the end of the message
Message termination
_____________ Is the ability to detect errors in the original information transmitted and types of noise on the communication channel
Security
In the gas flow calculation case, when you increase the differential pressure you will see the gas flow will decrease.
False
In a RTU flow loop, it show the flow is 56.3% of the range and the differential pressure to the transmitter has a range of 0 to 100 inches H2O. The differential pressure in engineering units is
31.6 in H2O
Which of the following is not one of the main categories of pipeline failure
Operation within design limit
RTU configuration program is stored in
EEPROM
Which part of the message format provides the signals to synchronize the receiver and transmitter
Message Establishment
The term used for obtaining data from sensors via amplifiers and multiplexers and any necessary analog digital converters is
Data acquisition
The computing device in the field that contains input/output (I/O) terminals connected to the transmitters and final control actuators
RTU
PLC is a common component of SCADA system
True
The MTU consists of the following
Driver, Database, HMI
In gas flow calculation case, when you decrease the orifice diameter you will see the flow decrease
True
Which one of the following is not a purpose of pigging technique
Repairing
Operations and supervisory personnel can communicate with SCADA systems via radios, telephone line modems, networks, the internet, satellite links and/or cellular telephone systems
True
Gas flow measurements using flow-computer require a total gas composition equal to 100 percent
True
In Unity Pro XL PLC programming, “I” is used for output and “Q” is used for input
False
In Gas Flow measurement case, when you decrease the statics pressure you will see the gas flow increase.
False
An orifice mass flow equation used for gas flow calculation is
AGA-3
The pump status is often transmitted from the RTU to the MTU
True
Communication by half duplex means
Data travels in both directions but not at the same time
ASCII is an acronym that is defined as
American Standard Code for Information Interchange
In a token passing protocol with a large number of nodes, the data transfer is
Relatively slow
The advantage of using fiber optics as a communication media is
Noise immunity
The term that refers to a communication system capable of communications in both directions simultaneously is
Full-Duplex
Noise signals induced by high voltage cables in the same tray are called
Noise, communications interference, cross talk
ISA/OSI acronym means
International Standards Association / Open System Interconnect
