Add a second ladder rung

Use the following steps to add a second rung that includes:
  • An on-delay timing.
  • Branches with coils and assigned variables.
After you add and configure the ladder diagram (LD) elements described in this task, rung 1 (the second rung) of the program will operate as follows:
If the East-West yellow traffic lights are on for at least two seconds, change the East-West traffic lights from yellow to red and the North-South traffic lights from red to green.
To add a second ladder rung
  1. From
    Toolbox
    , drag Add rung button and place it under the first rung.
  2. If the East-West yellow lights are on for at least two seconds, change the East-West lights from yellow to red and the North-South lights from red to green.
  3. Add an XIC to the beginning of rung 1 and assign the variable
    EW_YELLOW_LIGHTS
     to the XIC.
  4. Add a TON to the right side of the
    EW_YELLOW_LIGHTS
     XIC and assign the variable
    TON_2
     to the TON.
  5. In the box beside
    PT
    , enter
    T#5s
     for a time constant of 5 seconds, and then select
    Enter
    .
  6. Use similar steps to add the following LD elements to rung 1:
    LD elements on rung 1
    LD element
    Location
    Variable
    Three branches
    Right of the block
    N/A
    OTU
    First (top) branch
    EW_YELLOW_LIGHTS
    OTL
    Second branch
    EW_RED_LIGHTS
    OTU
    Third branch
    NS_RED_LIGHTS
    OTL
    Fourth (bottom) branch
    NS_GREEN_LIGHTS
    The second rung looks similar to the following image:
    Traffic light - the second rung
  7. Save the project by doing one of the following:
    • From the menu bar, select save button.
    • From the
      File
       menu, select
      Save
      .
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