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Timer operation


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I have a (probably simple) question regarding Timers.  Specifically, TOFF Timers.  I have the simple ladder block below (TOFF is preset for 1 second):


When "I Button" is pressed the entire rung in energized immediately as I expect.


However, when "I Button" is released,  The "ButtonState.Out" is delayed for 1 second before de-energizing but the "O OutState" contact goes off immediately.  Shouldn't the "O OutState" be delayed for 1 second before turning off (which is what I want)?



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  • MVP 2023

No, when you release I Button, power flow to O Outstate is discontinued immediately. Break your logic up into two ladder rungs and it will work.

Understanding power flow is essential to ladder logic.

Edit: I see you may be fooled by ButtonState.Out being red. Don't be - that's only showing you that if there was power flow to the bit then it would continue on to the coil, but since there is no power flow to the bit, there is nothing to transfer to the coil.

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