Flashcards in Chapter 20 Deck (34)
A communication network exists when two or more devices are connected together by some type of media for the sole purpose of exchanging information
Bandwidth is the speed at which information can be transferred.
Which is not a type of Network Category:
The LAN system is the largest type of Network.
The three network topologies are:
Ring, Bus, Star
The two topologies that are not commonly used in industrial plants are:
Ring and Star
Shielded twisted pair cable is most often used in offices and buildings.
Which of the following is not a type of twisted pair cable?
Coaxial cable is used widely in industrial control networks because:
It's immunity to electrical noise generated by equipment.
Coaxial cables have characteristic impedance's, 50 ohms, 75 ohms, etc.
The two typical devices to convert electrical signals into light are:
LED and laser
Fiber optic is the best type of network media because:
It's high data rates over long distances.
It's immunity to electrical noise.
It carries no current so that it is not a fire hazard.
Electromagnetic Interference or Electrical noise
Running a cable in steel conduit does not provide excellent EMI protection.
False. Steel conduit is excellent protection.
Any device connected to a network must have some means of identification so that it only receives the messages that are intended for it.
Which of the following is an example of a typical residential IP network address?
What is the most common access method used in industrial control networks?
Token Passing Access Method
Which Access Method gives nodes equal rights to transmit, without waiting for permission?
CSMA/CD Access Method
Network communication protocols are sets of formal rules on how to transmit and share data across a network. OSI is one of these protocols and stands for:
Open Systems Interconnect
What layers are require for the OSI model to operate?
Physical, Data Link, and Application
A message is a common term used to describe information transmitted via a network.
If a message is too large for one data packet, the message is broken up into several data packets and each is given a sequence number.
Proprietary networks, as opposed to open system network protocols, allow devices from many different manufactures to be used.
Some of the most common device and process bus protocols used today are:
DeviceNet, Foundational Fieldbus, and Profibus-DP
Information networks work at the middle level of the control system.
False. They work at the highest level.
Control networks use which network access protocol?
Token Passing (peer-to-peer)
Foundation Fieldbus, established in 1994, is a single international open bus standard for hazardous environments that enables devices of different manufacturers to be integrated into one system.
Which bus has a faster communication speed?
Profibus was developed by ______, Modbus by ______, and ContolNet by ______.
Siemens, Modicon, Allen-Bradley