Industrial Controls and PLCs Flashcards
What is a relays purpose?
It uses low voltage to switch to high voltage
Remember these
Single pole, single throw relay
Single pole, double throw relay
Double pole, single throw relay
Double pole, double throw relay
Throw is the number of points a switch can adopt
Number of poles described how many separate circuits are controlled by a switch
What is a latching relay?
A relay that stays in the on position after a brief application of power
What are logic devices?
The decision making devices of electrical control systems
What are the three possible functions of relay logic?
The AND function
(This and this must happen to accomplish this)
The OR function
(This or that must happen to accomplish this)
The NOT function
(This most not happen if you want to accomplish this)
What is relay logic memory?
The ability to detect and store, by electrical mean, the information that an input function has taken place
In electrical what does normally closed mean?
It means that electrical current can move through the “contact” to the next part
In electrical what does normally open mean?
It means no flow of electrical current can take place as there is a break in the line.
What shape is a pressure switch?
A half circle
What shape is a fluid level switch?
A full circle
What is a master control relay?
They are used to shut down the control power to multiple controls quickly for a certain machine or area of an operating plant.
What’s an advantage of using plcs over relays?
They’re much faster
What is ram and rom?
RAM
Random access memory
-Designed so that info is easily stored and retrieved, needs power to store info
(Volatile)
ROM
Read only memory
-designed to permanently store data and programs
(Non-volatile)
What does XIC mean?
What does XIO mean?
XIC
-examine if closed
XIO
-examine if open
