Section 1 Flashcards
In a refinery, a computer used to keep track of product shipping schedules would exist at what
network level?
Information level bus
A pipeline control system uses RTUs at each remote pump station. What network level do they
operate in?
Control level buses
Give three examples of DTEs that can be used in a control system.
Data terminal equipment in a control system may consist of:
PCs, PLCs, RTUs, and DCS
Give an example of a DCE you might find at home?
Data communication equipment that could be found at home:
Wifi router, telephone, satellite dish
Describe the 3 types of communication modes.
1) Simplex: one channel one way way only
2) Half Duplex: one channel that can send both ways but only one at a time
3) Full Duplex: two channels that can transmit data at the same time
What communication mode is required for fax machine operation?
Full Duplex
A compressor is controlled by a PLC system. Attached to the PLC is a display unit DTE that
indicates the compressor pressure and temperature for the benefit of operating personnel. What
communication mode could be used?
Simplex
You are bench testing a smart transmitter. You write a program so that the transmitter sends the
pressure reading every time you press the spacebar. What communication mode could be used?
Half duplex
How many DCEs are required to connect two DTEs together?
Zero or some multiple of 2
Is a mark a binary one or a binary zero? Is a space a binary one or a binary zero?
Mark = 1
Space = 0
What is a communication protocol?
A set of rules for transferring information
What is the difference between synchronous and asynchronous communication?
In a synchronous transmission all devices use a common clock generated by an external device. These are useful for short links.
An asynchronous transmission runs on independent clocks. Each transmitted byte has a start and a stop bit to synchronize the clocks and end the transmission.
