solomoneli Posted July 27, 2018 Report Share Posted July 27, 2018 I'm writing a pretty basic couple of nets, and I can't get a pump to turn on in a certain instance. It turns on in net 2, but not Net 1. Can somone please explain what I'm doing wrong? And how I can fix it? Quote Link to comment Share on other sites More sharing options...
MVP 2022 Flex727 Posted July 28, 2018 MVP 2022 Report Share Posted July 28, 2018 Direct coils should be used in one, and only one, place in your program. In your case, you are turning it on in net 1 then turning it off again in net 2. The state doesn't get written to the physical output until after it's turned off in net 2. We have a saying with ladder logic - "the last one wins". Figure out all the conditions you need to turn the coil on and write them into a single net. The exception to this is Set & Reset coils activated by a transition contact. You can have those in multiple places if you choose. Quote Link to comment Share on other sites More sharing options...
MVP 2022 Joe Tauser Posted July 30, 2018 MVP 2022 Report Share Posted July 30, 2018 Flex speaks truth. In addition- You've made good use of positive transitionals to help keep your logic from getting stuck. Each net is considered one logical statement in UnitronicsLand. Each of your nets has three statements - don't do that. Separate timer contacts from their coils, too. I realize this looks inefficient compared to your logic, but if you look at the compiled logic - STL Quick View - of what you've written you'll see it's rather messy. Extra nets have zero memory cost when the logic is compiled. Joe T. Quote Link to comment Share on other sites More sharing options...
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