Enter Ladder Logic

Ladder Logic

MapleLogic offers ladder diagram language for making PLC projects. Ladder logic is entered in Scan programs.

Basic Ladder Diagram Composition

• Standard ladder diagram Scan programs will look like the diagram above
  • Step Amount:
    • Each contact, coil, instruction, etc., cost a certain amount of steps.
    • The step number for the rung is listed on the far left of the rung (highlighted in dark blue).
  • Invalid Rung:
    • Incomplete rungs or invalid rungs that are added to the program, but not saved, will show a red vertical line on the far left of the rung.
    • This rung is incomplete since there is no resulting condition attached to the normally open contact M0.1 (highlighted in red).
  • Rung Number:
    • Each new and separate rung will display the rung number with the notation R.# on the far left of the rung (highlighted in gray).
  • Valid Rung:
    • New and complete rungs will show a green vertical line on the far left of the rung (highlighted in green).
  • Unsaved Rungs:
    • Any rung that has been added to a Scan program, or any rung that has a change made to it and has not been saved, will appear highlighted.
      • In this example, the top 3 rungs are highlighted in light blue.
  • Instructions:
    • Instructions added to the Scan program will typically have a black box around them while listing the instruction name and operands, if any (highlighted in red).
  • Execution Condition (Input) → Result Instruction (Output):
    • Typically, in ladder logic, execution occurs from left to right.
    • An execution, input button for example, triggers, and the resulting output, light for example, energizes (light lights up).

Add Rungs

Step 1: add more rungs to the ladder diagram, left-click the rung where new rungs will be added. New rungs will be added above the selected rung.

Step 2: Press CTRL + L to insert a new rung.

• If changes have been made to the ladder diagram, the changed rung will appear as a different color.

• Additionally the program title will have an asterisk, *, next to the name.
  • This means the program has NOT been saved since recent changes were made.

• Alternatively, to insert a new rung, left-click Edit and left-click Insert Row.

Step 3: To insert a rung below the currently selected rung, left-click the rung and press CTRL + Enter.

• The new rung will be inserted below the selected rung.

• Alternatively, to insert a rung below the selected one, left-click Edit and left-click Insert Next Row.

Columns

Enable/Disable Columns

Step 1: Columns can be added to the ladder logic program. To enable or disable column view, left-click View and left-click LD Grid to toggle columns on or off.

Change Column Size

• The amount of columns per rung can be increased or decreased.

Step 1: To change the amount of columns, left-click View left-click Change LD Col.

Step 2: Specify the number of columns to display per rung.

• Minimum: 9
• Maximum: 80
• Default: 11

Step 3: Left-click OK.

• The number of columns will change.

Toolbar and Tools

Step 1: To use the ladder logic toolbar, left-click View.

• The ladder diagram toolbar has 14 different components:
  • Arrow
  • Erase Vertical Line
  • Delete Vertical Line
  • Horizontal Line
  • Invert
  • Normally Open Contact
  • Normally Closed Contact
  • Positive Transition-Sensing Contact
  • Negative Transition-Sensing Contact
  • Coil
  • Application Instruction
  • Comment
  • Function Block

Arrow

• The arrow tool will restore the mouse cursor if it is being occupied by another MapleLogic component

Erase

• The erase tool will delete the components of the ladder diagram.

Erase Tool

Step 1: Left-click on the component to delete

Step 2: On the tool bar, left-click Erase

• Optionally, use the DELETE key on the keyboard

• The erased component will be deleted

Vertical Line

• The vertical line tool will create a vertical line between rungs.

Vertical Line Tool

Step 1: Left-click the rung to add the top of the vertical line.

• This will connect the currently selected rung with the below rung.

Step 2: On the toolbar, left-click the Vertical Line icon.

• Optionally, type SHIFT + F2 or CTRL + DOWN ARROW.

• A vertical line will be placed in front of the open contacts.
  • The lower of the rungs is no longer invalid.
• This creates a basic OR gate connection.

Delete Vertical Line

• The delete vertical line tool will remove a vertical line connecting two rungs.

Delete Vertical Line Tool

Step 1: Left-click the space next to the component to delete the connecting vertical line.

Step 2: On the toolbar, type CTRL + F2 or left-click below rung and type CTRL + UP ARROW.

• The two rungs will no longer be connected.

Horizontal Line

• The horizontal line tool will create a horizontal line in the same rung.

Horizontal Line Tool

Step 1: Left-click a space in the ladder diagram.

Step 2: On the toolbar, left-click the Horizontal Line icon.

• Optionally, type F2, CTRL + LEFT ARROW or CTRL + RIGHT ARROW.

• Individual horizontal lines will be added into the ladder diagram.

Invert

• The inversion tool will insert an inversion component to invert the signal from an execution condition.
  • If the signal from the execution condition is OFF (0), the resulting output will energize/be ON (1).
  • If the signal from the execution condition is ON (1), the resulting output will deenergize/be OFF (0).

Invert Tool

Step 1: Left-click the space to place the inversion.

Step 2: On the toolbar, left-click Invert.

• Optionally, type F4.

• The inversion signal will show a red slash through the middle of a horizontal line.

Normally Open Contact

• The normally open contact tool will place a normally open contact in the ladder diagram.
  • While ON (1), normally open contacts receive a continuous source of power and execute the resulting operation until powered OFF (0).
    • The resulting operation will be executed many times per scan.

Normally Open Contact Tool

Step 1: Left-click the rung to insert a new normally open contact.

Step 2: On the toolbar, left-click Contact A.

• Optionally, type F5.

Step 3: Enter the data register and left-click OK.

• The open contact will be added to the rung.

• Multiple normally open contacts can be added to a rung.
  • The creates a basic AND Gate connection.

Normally Closed Contact

• The normally closed contact tool will place a normally closed contact in the ladder diagram.
  • While OFF (0), normally closed contacts output a continuous source of power and execute the resulting operation until powered ON (1).
    • The resulting operation will be executed many times per scan.
  • For more information, refer to closed contacts.

Normally Closed Contact Tool

Step 1: Left-click the rung to insert a new normally closed contact.

Step 2: On the toolbar, left-click Contact B.

• Optionally, type F6.

Step 3: Enter the data register and left-click OK.

• The closed contact will be added to the rung.

• Multiple normally closed contacts can be added to a rung.
  • Thos creates a basic AND Gate connection.

Positive Transition-Sensing Contact

• The positive transition-sensing contact tool will place a positive transition-sensing contact in the ladder diagram.
  • The resulting operation will be executed once each time the contact receives power.
  • The execution condition is executed on the rising edge of a pulse
  • For more information, refer to rising edge contacts.

Positive Transition-Sensing Contact Tool

Step 1: Left-click the rung to insert a new positive transition-sensing contact.

Step 2: On the toolbar, left-click Pulse Up.

• Optionally, type F7.

Step 3: Enter the data register and left-click OK.

• The positive transition-sensing contact will be added to the rung.

• Multiple positive transition-sensing contacts can be added to a rung.
  • This creates a basic AND Gate connection.

Negative Transition-Sensing Contact

• The negative transition-sensing contact tool will place a negative transition-sensing contact in the ladder diagram.
  • The resulting operation will be executed once each time the contact receives power.
  • The execution condition is executed on the falling edge of a pulse.
  • For more information, refer to falling edge contacts.

Negative Transition-Sensing Contact Tool

Step 1: Left-click the rung to insert a new negative transition-sensing contact.

Step 2: On the toolbar, left-click Pulse Down.

• Optionally, type F8.

Step 3: Enter the data register and left-click OK.

• The negative transition-sensing contact will be added to the rung.

• Multiple negative transition-sensing contacts can be added to a rung.
  • This creates a basic AND Gate connection.

Coil

• The coil tool will create a coil at the end of a rung.

Coil Tool

Step 1: Left-click on any space in the rung.

Step 2: On the toolbar, left-click Coil.

• Optionally, type F9.

Step 3: Enter the data register and left-click OK.

• The coil will be placed at the end of the rung.
  • Only one coil can be placed per rung.
  • It is advised to have one occurrence of each coil per scan program.

Application Instruction

• The application instruction tool will insert an application instruction into the ladder diagram.
• Most application instructions will execute a command/instruction when the execution condition is true.
  • Refer to the Application Instruction section for more information.

Application Instruction Tool

Step 1: Left-click on any space in the rung.

Step 2: On the toolbar, left-click Application Instruction.

• Optionally, type F10, or type any character on the keyboard

• The application instruction window will appear.

Step 3: Type the name of the instruction in the Instruction tab, or select the instruction category on the left and instruction on the right.

• The isntruction format will appear in the Instruction tab.

Step 4: Select the data registers required for the instruction.

Step 5: Left-click OK.

• Optionally, left-click Basic for a basic view of the instruction list.

• Left-click Details to return to the previous view.

• The instruction will appear after the execution condition.

Comment

• The comment tool will insert a comment into the ladder diagram for organizational use.

Comment Tool

Step 1: Left-click on any space in the rung.

• The comment will be placed above the currently selected rung.

Step 2: On the toolbar, left-click the Comment icon.

• Optionally, type F12.

Step 3: Enter the comment into the Input Comments window.

• To enter a new line, type CTRL + ENTER.

• To add a date to the comment, left-click Add Date.
• To add a row of asterisks (*), left-click *******.
• To add a row of dashes (-), left-click ——–.
• To change the color of the comment, left-click Color.
• To add the comment as a historical comment to use elsewhere, left-click Add Cmt.

Step 4: Left-click OK.

• The comment will appear above the rung.

Add Function Block

• The add function block tool will insert a function block into the ladder diagram.

Add Function Block Tool

Step 1: Left-click on any space on the rung.

Step 2: On the toolbar, left-click Add FB.

• Optionally, type SHIFT + F9.

Step 3: Left-click a function block group.

Step 4: Left-click a function block.

• The function block requirements will appear in the FB Preview window.

Step 5: Left-click OK.

• The function block will appear in the ladder diagram.

Step 6: Double left-click on the function block to edit the data registers.

Step 7: Enter the data registers under the Device tab.

Step 8: Left-click OK.

• The function block will now display the data registers.

Save Program

Step 1: To save the program, left-click Home and left-click Save All.

• Optionally, left-click Project and left-click Save Program.