MrEngineer Posted October 20, 2020 Report Share Posted October 20, 2020 Hey everyone! I need a little bit of help with my ladder logic program 😅 So the thing is, I am controlling three valves with Samba 43. The whole process is about opening and closing valves: To start the cycle I need to set all my outputs to low state. This is the condition that allows me to start the process. Then I press the START button on the HMI. The first valve opens by going into the high state. After two seconds, the second and the third valve open. They wait in that state for another two seconds then they close. As soon as they close, the first valve closes as well. The last step is to open first and second valve again. They wait there until the initial condition button is pressed. That's it! I'm not quite good in ladder logic so I tried to simplify it as much as I could, but it doesn't work.. Any ideas? Thank you so much, KR   Quote Link to comment Share on other sites More sharing options...
MVP 2023 Flex727 Posted October 20, 2020 MVP 2023 Report Share Posted October 20, 2020 You seem to be mixing up contact and coils. Also in your second ladder rung you have two separate logic threads. Do not do that. Further, that second logic thread is screwing everything else up - you are forcing MB 3, O 2, and TD 1 on all the time. 58 minutes ago, MrEngineer said: To start the cycle I need to set all my outputs to low state. This is the condition that allows me to start the process. Then I press the START button on the HMI. The first valve opens by going into the high state. After two seconds, the second and the third valve open. They wait in that state for another two seconds then they close. As soon as they close, the first valve closes as well. I would do that part this way: 58 minutes ago, MrEngineer said: The last step is to open first and second valve again. They wait there until the initial condition button is pressed. This is not clear to me. It looks like you've left out a step as you state that the first valve closes then you immediately say it opens again. 1 Quote Link to comment Share on other sites More sharing options...
MrEngineer Posted October 20, 2020 Author Report Share Posted October 20, 2020 Thank you @Flex727! The combination of Positive Transition Contact and Set Coil made the thing much clearer and easier! 45 minutes ago, Flex727 said: This is not clear to me. It looks like you've left out a step as you state that the first valve closes then you immediately say it opens again. Here's the visual representation of the state in the 3rd net (according to your image) The 2nd and the 3rd valve need to make space for the main cylinder (1st valve) and then as soon as it is enough space for both (2nd and 3rd valves) cylinders they get back to "high" state. And that's the whole cycle... Thank you very much  Quote Link to comment Share on other sites More sharing options...
Isakovic Posted October 23, 2020 Report Share Posted October 23, 2020 If there is a possibility of cylinders colliding might I suggest using position sensors or limit switches as conditions in your program. It shouldn't be a big investment, but it will be safer than only timers. Quote Link to comment Share on other sites More sharing options...
MVP 2023 kratmel Posted October 23, 2020 MVP 2023 Report Share Posted October 23, 2020 Maybe fastest way to build this type of application is using FB Drum sequencer. Please read help topic about this FB and try to run this idea in Samba. Simple place checkbox for needed MB and run outputs via this MB. Please open Drum example projects in visilogic Help menu - you can easly implement one of them for your hardware. Quote Link to comment Share on other sites More sharing options...
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