Question

7-1 Write a documented program that will simulate the on-delay relay timer schematic shown. Use the 1/0 Simulator screen and the following addresses to simulate the program: Si_1:1/0 L1_0:2/0 TON_T4:0 L1 L2 S1 (TD TD1 Sequence of operation: S1 open, TD de-energized, TD1 open, L1 off S1 closes, TD energizes, timing period starts, TDI is still open, L1 is still off After 10 s, TD1 closes, L1 is switched on S1 is opened, TD de energizes, TD1 opens instantly L1 is switched off

Answer 1

ANSWER:

The PLC ladder logic diagram as stated above is shown below.

LAD 2: X 000 은 EN S1 -TON Timer On Delay Timer 14:0 Time Base 0.1 Preset 100 Accum 0 10 sec TIMER TD1 DN T4:0/DN 0:2/0 001 DONE BIT OF TIMER TD1 L1 002 ENDS

Input/output/timer	TYPE
I:1/0	NORMALLY CLOASE CONTACT	NORMALLY OPEN SWITCH S1
T4:0	ON DELAY TIMER	10 sec delay timer TD1
T4:0/DN	normally open contact	Done bit of timer T4:0
O:2/0	Output Coil	light L1

The program works as stated in question.

Rung 000: S1 is pressed i.e., I:1/0 becomes Normally closed and energises the timer T4:0.

               Timer's Time delay = Preset value * timer base = 100* 0.1 = 10 seconds

Rung 001: After 10 sec, the accumulated value of timer becomes equal to its preset value. Then the done bit of timer, T4:0/DN becomes active and its NO contact becomes Normally closed which energises the ouptut L1.

when the switch S1 is opened, I:1/0 becomes NO again, timer de-energises and its Done bit becomes Low. Thus output L1 turns off.