Whatisthepurposeofinterconnectingthetwotimers How much time

Whatisthepurposeofinterconnectingthetwotimers?

How much time must elapse before output PL is energized?

What two conditions must be satisfied for time T4:2 to start timing?

Assume that output PL is on and power to the system is lost. When power is

restored, what will the status of this output be?

When input PB2 is on, what will happen?

When input PB1 is on, how much accumulated time must elapse before

rung 3 will be true?

Solution

a) The purpose of interconnecting timers is to make the output to turn on after ellasped times on the timers i.e

b) output PL energized after ellapsed time of 2900 + 1780 sec .

we know RTO - rententive timer on works as below

i) When input to timer is true and accumulated value is less than prset value then timer increases by 1.

ii) when input to timer is true and accumulated value is greater than prset value then timer doesn\'t increase and make DN to 1. Which will on the output.

iii) We need give another signal to reset the timer.

c) The timer T4:2 will start timing only when DN of T4:1 is 1 and PB1 is 1 and accumulated values is less than prset value.

d) If output is on and suddenly power lost then then output will be on after power restored because the timer accumulates prset value and so DN bits is 1 for both timers.

e) When PB2 is on it will reset the timers and makes DN bit of timers zero.

f) if PB1 is on the time elaspsed for the rung 3 to be true is 2900 sec.