This page explains ladder-cell editing, contacts and coils, box functions, series and parallel connections, edges, and a self-holding circuit.

About screenshots: Screenshots use the Korean user interface. Button positions, icons, and keyboard shortcuts are the same.

Read ladder logic from left to right. A coil operates when the condition formed by the contacts reaches it through the connecting lines. A circuit arranged on one line is called a rung.

• ① Toolbar: Select contacts, connecting lines, coils, and edges.
• ② Ladder grid: Place elements in cells and connect the circuit.
• ③ Grid status bar: Shows the selected cell's coordinates and type. R1 C0 is the first cell on the first row.

You can place a tool in any of these ways:

1. Select a cell and press the tool's shortcut.
2. Select a cell and click the tool on the left toolbar.
3. Drag the toolbar button onto the target cell.

Click the cell that you want to edit, or move the selection with the arrow keys. Hold Shift and press an arrow key to select multiple cells.

When editing a contact or coil, enter an address or registered symbol. Matching items appear in the autocomplete list as you type.

Shortcut focus: Use arrow keys and ladder shortcuts such as F2 through F12 while the ladder grid has focus. When the code editor has focus, arrow and clipboard shortcuts edit the code.

Delete, which clears a cell, behaves differently from Ctrl + Delete, which pulls following cells to the left.

Right-click a ladder cell to select Insert Cell, Delete Cell, Add Row, or Delete Row. The shortcuts in the table run the same commands.

Insert Cell moves cells to the right from the selected position up to the nearest available space. If no space is available on the right, the circuit remains unchanged and a message appears. A coil at the end of the row does not move.

Delete Cell removes the selected cell and pulls the cells on its right to the left. The coil stays at the end of the row, and a gap before the coil is filled with a connecting line.

Add Row creates an empty row above the selected row. Vertical lines that crossed the insertion point continue through the new row.

Delete Row removes the entire selected row and pulls the rows below it upward. Vertical lines that crossed the deleted row reconnect to the remaining circuit.

• Ctrl + C: Copy the selected cells
• Ctrl + X: Cut the selected cells
• Ctrl + V: Paste at the selected position
• Ctrl + Z: Undo the last ladder edit

Copied cells can be pasted into another ladder tab or into a separately running MPINO Studio 2 window.

A horizontal line connects cells on the same row. A vertical line joins upper and lower branches.

A vertical line is not a separate cell. It adds a connection from the right edge of the selected cell to the row below. Press F6 again at the same position to remove it.

Use horizontal lines to form a series circuit on one row and vertical lines to join the branches of a parallel circuit.

NO and NC contacts read an ON/OFF memory state or the result of a comparison. A NOT contact reverses the condition calculated before it.

Select a cell, press F2 or F3, and then press Enter. Enter a bit address such as P0, M0, or D0.1, or enter a registered symbol. See Phase 2 · Understand Memory for memory-address formats.

You can enter a comparison instead of an address in an NO or NC contact. For example, D0 > 10 is true when D0 is greater than 10. A comparison in an NC contact conducts when the expression is false.

Enter one comparison in each contact. To combine several comparisons, connect separate contacts in series or parallel instead of entering && or ||.

A NOT contact reverses the condition calculated up to its position. It does not take an address and is placed with F10. When the preceding condition is OFF, the condition after the inversion is ON; when the preceding condition is ON, the condition after it is OFF.

Use no more than one NOT contact in a branch.

A standard contact conducts while its condition remains true. An edge contact conducts for one scan only when the input changes state.

After placing an edge cell, enter the bit address or symbol whose change will be detected. Each edge cell tracks its previous state automatically, so you do not need a separate memory address for that state.

Use Positive Edge for an action that runs once when a button is pressed. Use Negative Edge for an action that runs once when a button is released.

A standard output coil writes the result calculated by its contacts to a bit address on every scan. The coil address is ON while the condition is ON and OFF while the condition is OFF.

1. Select a cell on the row where the coil will be placed.
2. Press F9 or select Output Coil from the toolbar.
3. Press Enter or double-click to open the editor.
4. Enter the bit address or symbol that will store the result.

The output coil is placed automatically at the right end of its row, and empty cells before it are connected with horizontal lines.

Check the output address: Before using a P address in an output coil, confirm under Settings → Ladder Pin Map Settings that it is an output on the selected board.

A standard output coil follows its condition continuously. SET and RESET coils store a value when their conditions turn ON.

M0 NO → P32 SET stores ON in P32 when M0 turns ON. P32 stays ON after M0 returns to OFF.

To turn the stored value off, enter the same address in a RESET coil. In M1 NO → P32 RESET, P32 is stored as OFF when M1 turns ON.

When using a SET coil, also provide a RESET condition that releases the stored value.

A box function runs a timer, counter, calculation, transfer, or another command when the condition calculated on its left is ON.

1. Select an empty cell on the row where the box function will be placed.
2. Press Ctrl + Enter or select Box Function from the left toolbar to open the editor.
3. Select a category and command to place the command syntax in the input field.
4. Enter the addresses and values, then select OK.

A box function is placed at the right end of its row like an output coil. It runs while the contacts on its left are ON. With no contact on the left, it runs on every scan.

View the box function list →

• Series connection: Power reaches the next cell only when every contact conducts. In M0 NO → M1 NO → P32 coil, P32 turns ON only when both M0 and M1 are ON.
• Parallel connection: Power continues after the branches rejoin when any connected branch conducts. If M0 and M1 are connected in parallel, P32 turns ON when either one is ON.

Combining series and parallel connections can express a condition such as “(M0 or M1) and M2.” Read from the left, and separate the conditions at the points where parallel branches split and rejoin.

A self-holding circuit connects an output coil's auxiliary contact in parallel with the start contact so that the output remains ON after the start signal disappears.

Build the circuit in this order: [M0 NO ∥ P32 NO] → M1 NC → P32 output coil.

1. Connect the M0 NO contact and P32 NO contact in parallel.
2. Connect the M1 NC contact in series after the parallel branches.
3. Place the P32 output coil at the right end of the row.
4. When M0 turns ON, P32 turns ON and the P32 auxiliary contact also conducts.
5. After M0 returns to OFF, the P32 auxiliary contact maintains the conducting path.
6. When M1 turns ON, the NC contact opens and P32 turns OFF.

M0 and M1 are internal-memory addresses used to explain the sequence. Replace them with P input addresses for the selected board when using physical input terminals.

You can change shortcuts under File → Preferences → Shortcuts.

• Phase 7 · Menus and Preferences

• Phase 6 · Serial and Ladder Monitoring

• Phase 5 · Editing Arduino Code

• Phase 1 · Create Your First Project
• Phase 2 · Understand Memory
• MPINO STUDIO 2 User Manual

← Phase 2 · Understand Memory | Back to the MPINO STUDIO 2 User Manual