Question

* " we require a time-delay period Jonger than the maximum preset time allowed for the single timer striction of the PLC being used, we can use the following two PLC programs. Please calculate how much time could be delaved for each PLC code X0: start pushbutton; X2: stop pushbuton MO: internal relay; T10, TI1, and T12: timers, C10: counter, YO: motor) (8 points) Stwt TIO Tieer10 Tieeril Tieeri TI2 Tiser12 eter Time-delay period: 12 Step Start T11 %3 Timerll Tinerl1 CI0 K120 T11 Tinerll TO C10 Motor Time-delay period:

Answer 1

SOLUTION:

3.

for PLC logec diagram -3 Tiner Preset Value Time Value K 30000 Зоро део Tho TH T12 Taking time base = 0.1 Preset Value = Time - Time base K 30000 30cosec K32000 3200 sec We see that Timer Tio is actualed/ energized by Start to and timen till es energized by the No contact of timer Tto. Similarly the timer T12 is energized by the No contact of timer TIL. We know that the No contact of a Timer becomes NC when the accumulator value of timer reaches the preset value. Thus, timer To get started by xo. Til starts when timer To is done and Timer T12 is started when timer Th is done At last, when time T12 is clone, its No contact becomes NC and motor yo gets energized So the total time delay is, Tiine-delay period = 3000 +3000 + 3200 = 9200 BEL = 9200 sec = 153.33 minutes.

4.

In the pic ladder logec diagram - 4 It is clearly seen that in the third rung, the timer Til is energized No button and We also see a No to contact of the timer Is itself. The NC contact of the timen II becomes No when timer is done. In the fourth rung, DIRD contact of Times is used, it becomes NC when timer goes from on to off stage ie, when times is reset. And when the DIFD contact changes its state from No to NC, then the accumulated value of Counter Clo increases by to

Time of Timer = Preset-Value & and Time base 2 800 X0.1 = 80 sec So after 80 sec, the NC contact of Timer Til becomes No and &. makes the third rug false this resetting the timer TIL Meanwhile, while the times Th gets reset from on to off slate, then the DIFD contact of timer becomes no for moments and to actuates the counter clo. We see that after 120 times the timen TIL is reset, the counter value of cto reaches 120 and counter is done. Then, the no contact becomes Nc and Motor Yo gets energized. Thus, timan TIL has to run 120 times before yo is on. Time-delay preniod= 120x80 sec - 9600 sec =160 min