Question

9. Consider a PLC system with the following inputs and outputs. Design a ladder diagram that does the following: • A timer counts up to 1.5 seconds, resets itself, and then repeats Every time S1 is on and the timer makes it to 1.5 seconds, a counter increments its accumulated value. PL1 turns on any time that the count of the counter is 20 or higher. The counter should be reset whenever PL1 is first turned on (i.e. transitions from off to on) PL2 should blink on and off any time that S2 is on. The blink should be on for 0.5 seconds and off for 0.5 seconds. PL3 should turn on whenever S1 and S2 are both on and PL3 should remain on for 8 seconds after either S1 or S2 turn off. Inputs as1 Fas2 Outputs le - *

Answer 1

Ladder diagram solution

1)start and compare counter

%DB1 "IEC_Timer_O_DB M10.1 M1.0 TON timer bit" Tíme HA - INQ t#1.55 - PT E T - M1.0 timer bit" "S1" %DB2 IEC Counter O_DB" M10.1 "S1" %M10.0 'sensor count bit CTU Int 1 -CUQ %MW100 Tag_5 CV — M1.1 Tag_2" HE 0— PV %M1.1 *Tag_2 20 %M1.1 *Tag_2 Int %MW100 Tag_5

2) PL1,PL2,PL3 ON and OFF

%M1.1 Tag_2 %M1.2 "PL1" DB4 %DB3 "IEC_Timer_O_ DB_1" "IEC_Timer_0 DB_2" %M10.2 TOF %M1.3 *PL2 TP Time %M1.3 *PL2" "S2 Tíme 1 사 - IN Q- T — -- — IN T#0.55 – PT T#0.55 - PT E ET — -- %DB5 "IEC_Timer_O_ DB_3 TOF %M10.1 "S1" %M10.2 "S2" %M1.4 PL3" Tíme T#85 — PT ET ...