Ladder Editor¶

The ladder editor is PiPLC's main programming environment — a visual workspace for creating and editing ladder logic programs.

Editor Layout¶

Area	Location	Function
Menu bar	Top	File, Edit, View, Runtime, GPIO, Tools, Help
Toolbar	Top	Quick actions and engine selector
Instruction palette	Left	Categorized instructions for drag & drop
Ladder editor	Center	Main workspace with program tabs
Properties panel	Right	Configuration of the selected element
Simulation panel	Bottom	Virtual I/O, watch panel, diagnostics
Engine selector	Toolbar	Create, select, and delete engine contexts

Editing Rungs¶

Add rung: Right-click context menu or toolbar button
Delete rung: Select and press ++delete++
Reorder rungs: Drag & drop
Comments: Each rung supports a title and multi-line comment
Numbering: Rungs have unique numbers per program
Undo/Redo: ++ctrl+z++ / ++ctrl+y++ for all operations

Adding Instructions¶

Open the instruction palette on the left
Drag an instruction onto a rung
Configure its address in the properties panel (e.g., I:0/0, T:0, N:5)
For timers and counters, set preset values

Tip

You can also right-click on a rung to insert instructions from a context menu.

Right-clicking anywhere on a rung shows a context-aware menu. The available actions depend on what you clicked on and whether you have a selection:

Action	When it appears	What it does
Insert Rung Here	Always	Inserts a blank rung at the right-clicked rung's position
Insert Rung After	Always	Inserts a blank rung below the right-clicked rung
Copy Rung	Right-click on a rung	Serializes the rung to the clipboard. Uses the same MIME type as ++ctrl+c++, so it interoperates with the standard copy/paste flow
Duplicate Rung	Right-click on a rung	Clones the rung via `Rung::clone()` and inserts the copy directly below
Paste Rung Before	Right-click on a rung with a rung-shaped clipboard	Inserts the clipboard rung(s) above the right-clicked rung
Insert Instruction ▸	Right-click on a rung	Submenu with all instruction types
Insert Branch	Right-click on a rung	See "Wrap-in-Branch" below
Add Path to Branch	Right-click on an existing branch	Adds an empty parallel path to that branch
Delete Instruction	Right-click on an instruction	Deletes that single instruction
Delete Branch Path	Right-click on a branch with > 1 path	Deletes the path you clicked
Delete Branch	Right-click on a branch	Deletes the whole branch
Delete Rung	Right-click on a rung	Deletes the entire rung
Delete Selected	A selection is active	Deletes all selected items

Wrap-in-Branch¶

Insert Branch with no selection inserts an empty branch (two parallel paths) at the right-click position. With a selection, it wraps the selected elements inside a new branch — the selection becomes path 0 and path 1 is left empty for you to fill in.

The wrap works at any nesting depth as long as the selected items share the same parent container:

Several contacts at the rung level → wrapped at rung level.
Several contacts inside the same branch path → wrapped inside that path (a nested branch is created).
A graphically-enclosed inner branch is treated as a single unit when you select it together with its siblings.

Selections that span unrelated containers (e.g., one element at rung level and another inside a branch path) fall back to the previous "insert empty branch at the click location" behavior.

Undo (++ctrl+z++) reverses the wrap.

Right-click preserves selection¶

Opening the context menu with a right-click no longer clears your current selection — the blue highlight stays visible while the menu is open, so it's always clear which items the menu's actions will operate on.

Runtime Visualization¶

During simulation:

Active rungs are highlighted in green
Wires show power flow (green = energized, gray = de-energized)
Current values are displayed next to contacts and coils
Timer/Counter instructions show ACC/PRE values in real time

Diagnostics Panel¶

The editor continuously validates the ladder structure:

Errors block execution
Warnings are shown inline
Click a diagnostic to navigate to the affected rung