How to create PLC Timer longer than 1 week

Discussion in 'General Electronics Chat' started by pandian, Jan 28, 2011.

  1. pandian

    Thread Starter Active Member

    Sep 27, 2009
    32
    0
    Hi,

    I trying to edit a ladder diagram with OMRON CS1G PLC.
    I need an alarm to be triggered after 3 months.

    If I use a combination of NO instruction with 1 minute interval and CNT instruction, the max count is 9999 x 1 minute, which is equal to 166.65 hours or 6.94 days.
    Is there any other special instruction/timer to count more than that?
     
  2. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    How about cascading counters? Compare the count bit of the first counter with a constant 9999 then increment the second counter one step. Reset the first counter and let it count up to 9999 again and repeat. You'll get to ~three months in 12 counts.
     
    pandian likes this.
  3. pandian

    Thread Starter Active Member

    Sep 27, 2009
    32
    0
    Hi brother,

    thanks a lot. I didn't even thought about it. I'll try.
     
  4. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    what possible use could a time dependant alarm of 3 months be?, unless it was an embedded service call. Query your system date and time registers.
     
  5. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    There are, unfortunately, some malicious applications of long delay timers.
     
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