Chapter 4

Question 1

bits on timers

Answer 1

• TT bit (timing): comes on once the timer is activated
• DN bit (done): comes on once the timer is done
• TT and DN bits cant be on at the same time

Question 2

retentive type timer (RTO)

Answer 2

• remembers the seconds it has gone through even when power has been removed
• needs a reset coil to reset

Question 3

3 types of timers

Answer 3

• on delay
• off delay
• retentive

Question 4

binary principle

Answer 4

idea that many things can be thought of as existing in either on/off (1/0) state

Question 5

OR gate

Answer 5

output is 1 if one or more of the inputs are 1

Question 6

NOT gate

Answer 6

only one input, called an inverter

Question 7

exclusive OR gate

Answer 7

output is high only when one output or the other is high but not both
commonly used for comparison of two binary numbers

Question 8

blocks in PLC program (can find in MOVE)

Answer 8

• bitwise AND
• bitwise inclusive OR / NOT
• bitwise exclusive OR