How do I turn on an output momentarily

gappvembe

Member
Join Date
May 2007
Location
MI
Posts
81
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Micrologix 1500
RSLogix 500
Here is what I'm doing:
There are these cycles that a machine goes through.
It's variable by the operator, so that is why I have the math, subtract functions on there.
When I am in any of the last three cycles AND B3:20/14 (#14 Draw Vacuum Latch Cycle #14) is activated, I want to turn on the Timing Relay On.
What this will do is Turn on an adjustable True OFF Delay Relay.
The problem is, the OFF Delay doesn't start until power is removed from it's coil.
I need a way the output will only come on once when the conditions are met, and then shut off and be ready for the next cycle.
I don't know what to put in the (Here) area.
I don't know if I am trying to over-simplify the program, or an answer is just over my head on this one.
Thanks
 
Oh, that might be it.
I originally had a DN, but the timer kept looping, and never shutting off the output.
I'll try this as soon I can.
 
Last edited:
My example has some limitations...
1) If the rung is true less than 1/2 second, the timer will go false and the output will be on less than 1/2 second. You could guarantee that it finished by putting another branch at the beginning of the rung with the TT bit from the timer in parallel with the other conditions.
2) If the first part of the rung goes false and then true again, the timer will start again and turn on the relay again. This may be desirable, just something to be aware of.
 
My example has some limitations...
1) If the rung is true less than 1/2 second, the timer will go false and the output will be on less than 1/2 second. You could guarantee that it finished by putting another branch at the beginning of the rung with the TT bit from the timer in parallel with the other conditions.
2) If the first part of the rung goes false and then true again, the timer will start again and turn on the relay again. This may be desirable, just something to be aware of.
I can say, for this particular application, this wouldn't ever happen.
Here it is in it's final running form. Just checked it, boss was happy (he had a day with it Wednesday, and wanted me to change it to this):
7OK21.png

Thanks again Okiepc. Glad this was a simple one.
 

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