PowerPoint Flashcards
What does RAM stand for and what is it used for?
Random Access Memory
Ram is used to store PLC programs. It may be changed or erased over and over
What is ROM and what is it used for?
Read-Only Memory
Rom is used by the manufacturer to store the operating system. Once data has been written onto a Rom chip, it cannot be removed, it can only be read.
What does EEPROM stand for?
Electrically Erasable Programmable Read Only Memory
What does EPROM stand for?
Erasable Programmable Read Only Memory
How is a PLC’s memory measured
Measured in Words.
What are the 5 basic parts of a PLC?
Power supply
CPU- Central processing unit
I/O section
Rack
Loader
What is used to isolate the field wiring from the PLC’s circuitry?
Opto-Isolation
What is the voltage range of Modules?
5V DC- 240V AC/DC
What are the two types of input devices?
Discrete(digital)
Analog
What does Analog mean?
Continuously Varying
What are analog input used to sense?
Voltage, Current, Speed, Pressure, Temperature, Humidity, ETC.
What are the two types of signals produced by analog sensors? Which is preferred?
Voltage signals and Current signals. Current signal is preferred because it eliminates voltage drop
What are pushbuttons, float switches, and limit switches considered to be?
Digital devices
How should signal wires be run from a sensor to a controller?
As short as possible
What type of wire is used for signal wires for analog sensors?
Shielded cable, to prevent magnetic fields from being induced onto the wires.
