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Feedback Variable in FBD

lqpleelqplee
edited February 2020 in PLCnext Technology & PLCnext Controls

Hello,
    I am working on FBD sheets and trying to connect a variable to an output of a function block as well as an input of another function block. I believe it can be achieved by "Toggle feedback variable". However, when I tried to do it, it doesn't work. Could you please give the idea what a feedback variable is? How to connect a variable between two function block in FBD sheets?

Thank you 

Comments

  • Martin PLCnext TeamMartin PLCnext Team

    Hello,

    You have the right idea about feedback variables, but I understand that feedback variables must somehow connect back to an earlier block in the sheet, i.e. be fed-back to an earlier block, rather than just continue on to a later block. I'm not entirely clear on the exact rules for a valid feedback variable connection, but one valid example is shown in the picture below.

    This picture also shows a way that you can connect the output of one block to a variable, and then on to another block, by splitting the output signal from the first block.

    2020 02 07 182031

    Hope this helps.

    ~ Martin.

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