I have to build a ladder diagram for a system which sounds the alarm if inside 60 seconds after pressing the start button,10 objects have passed.The alarm goes on until we press stop.In the system we have placed a sensor to identify the objects and the stop button to stop the alarm and to reset the system.Is my solution correct?

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Edit : T1 is the timer,C1 is the counter,S is sensor,C is the output of C1 K10

  • \$\begingroup\$ First, you could also add the TAG of "PLC". Second, Not all ladder logic is the same. You can help your question by defining for us explicitly what is "S" (presumably sensor), and "C" which is presumably the output of "C1 K10". \$\endgroup\$
    – Marla
    Feb 11 '16 at 20:51
  • \$\begingroup\$ Sorry I will do that right now.C means counter. \$\endgroup\$
    – Kami H
    Feb 11 '16 at 20:52
  • \$\begingroup\$ Welcome to EE SE Kami. Glad to have you here. The more you define your problem, the better answers and help you will get. \ \$\endgroup\$
    – Marla
    Feb 11 '16 at 20:54
  • \$\begingroup\$ How will the system behave if you reset it at T1 = 30 seconds? \$\endgroup\$
    – Tut
    Feb 11 '16 at 21:05
  • \$\begingroup\$ I thought about that but I also thought maybe its not necessary? When we hit reset for the counter,the timer is automatically resetted? \$\endgroup\$
    – Kami H
    Feb 11 '16 at 21:06

For "Start", you will need a "seal in contact", so that when start button is pressed, the "start" contact will maintain. (Also need to have "start" reset appropriately). Right now, as soon as "start" pushbutton is released, the timer will stop.

As @Tut mentioned, you will need to reset T1 during reset.

  • \$\begingroup\$ Thank you.Apart from these,is there any other mistake in my diagram? \$\endgroup\$
    – Kami H
    Feb 11 '16 at 21:07
  • \$\begingroup\$ Looks good as long as the Counter is also reset \$\endgroup\$
    – Marla
    Feb 11 '16 at 21:09
  • \$\begingroup\$ You mean Timer lol \$\endgroup\$
    – Kami H
    Feb 11 '16 at 21:10
  • \$\begingroup\$ No, I did mean counter. I don't know if your PLC resets the counter upon your RST command. \$\endgroup\$
    – Marla
    Feb 11 '16 at 21:11
  • \$\begingroup\$ So that next time Start is pressed, the counter begins again. \$\endgroup\$
    – Marla
    Feb 11 '16 at 21:12

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