SFC Editor (GRAFCET)

The SFC Editor (Sequential Function Chart) provides a graphical view of the step-and-transition sequence within a process, following the IEC 61131-3 GRAFCET standard. It visualizes how steps connect through conditions, making complex process flows easy to understand and edit.

Access: Open a module → Module Ribbon → Condition panel → SFC button.

⚠️ Important: Everything you do in the SFC Editor window will automatically update the steps and conditions in the Algorithm Design, and vice versa. Changes are always synchronized.

🔎 Overview

The SFC Editor renders the entire process as a directed graph where:

• Steps (phases) are shown as rectangular nodes with their step number and name

• Transitions (conditions of type Transition) are shown as labeled edges connecting steps

• Non-transition conditions (Continuous Action, Stored on Activation, etc.) are displayed directly alongside their parent step

• The graph supports parallel fork, parallel merge, and jump patterns for complex branching logic

🖥️ Window Layout

The SFC Editor window has the following areas:

📦 Working with Steps

Hovering a Step

When you hover over a step node on the canvas, action buttons appear:

Step Color Coding During Hover

When you hover over a step in the Phases Panel (left sidebar), the editor highlights the connections:

This visual feedback helps you quickly understand the flow: which steps lead into the selected step, and where it goes next.

🔀 Working with Edges (Transitions)

Edges are the lines/arrows that connect steps. Each edge represents a transition condition.

Edge Hover Behavior

When you hover over an edge:

• The edge turns blue

• The source step turns orange

• The target step turns green

This clearly shows the direction of the transition — from the orange step to the green step via the blue line.

Edge Label Actions

When you hover over the small label on an edge, you see the condition text and a set of action buttons:

Rerouting Edges

Click on an edge to select it, then drag its segments to reroute the path. The editor uses orthogonal (right-angle) routing for clean, readable layouts.

🔗 Linking (Off-Page Connectors / Teleports)

The Link feature works like an off-page connector in traditional P&ID drawings. It interrupts a long edge and replaces it with a pair of matching symbols — keeping the graph clean when source and target steps are far apart.

Creating a Link

1. Hover over an edge label and click the Link button

2. The edge is replaced by two matching teleport nodes with an identifier (e.g., "1-ngts")

3. The entry node appears near the source step, the exit node near the target step

4. Both nodes display a matching label so you can identify paired connections

Removing a Link

To convert a linked connection back to a continuous line, use the Direct (unlink) option that appears on linked edges.

Teleport Naming Settings

Click the Linking button (🔗) in the toolbar to open the Teleport identifier settings window:

🧩 Condition Display in the SFC

Transition Conditions

Conditions of type Transition are displayed on the edges (lines/arrows) that connect steps. The condition text appears as a label along the edge.

Non-Transition Conditions

All other condition types (Continuous Action, Cont. Action + Condition, Stored on Activation, Stored on Deactivation, Stored on Event, Custom) are displayed directly next to their parent step as attached boxes. Each non-transition condition appears as a small box alongside the step node, with an icon indicating its type:

You can right-click or hover these boxes to see options for editing, duplicating, or deleting the condition.

🧩 Graph Elements — Advanced

Parallel Fork (Simultaneous Branches)

A parallel fork occurs when a single condition has multiple target steps that activate simultaneously.

Parallel Merge (Synchronization)

A parallel merge occurs when multiple transitions from different source steps converge on the same target step.

• If all incoming conditions share the same text → Unified display (single shared label)

• If conditions differ → Mixed display (individual labels per incoming edge)

Jump Nodes (Teleports)

Jumps are visual shortcuts created by the Link feature. Each jump consists of an entry node near the source and an exit node near the target, both sharing a matching display ID.

Dangling Conditions

Conditions without any transition target assigned are called dangling conditions and appear as a list on their parent step node. This helps identify incomplete configurations that still need transitions.

⚙️ Toolbar Options

The toolbar at the top of the SFC Editor provides these controls:

📋 Phases Panel (Left Sidebar)

The Phases Panel on the left shows all steps in the current process with their number and name.

Features

• Hover a step to see visual connection highlights (orange = incoming, green = outgoing) drawn on the sidebar itself

• Drag and drop steps in the sidebar to reorder them

• Right-click or hover action buttons to Edit, Duplicate, or Delete steps and their conditions

• The sidebar scrolls independently of the main canvas

Process Selector

Above the Phases Panel, a dropdown shows the current process. You can switch between processes to view different SFC charts.

📤 Exporting the SFC

PDF Export

Click the Export button (PDF icon) in the toolbar to generate a PDF of the current SFC chart.

💡 Tip: The dotted canvas area shows what will fit on a single PDF page. You can place objects beyond the canvas boundary, but they may not appear in the PDF export. Arrange your steps within the dotted area for the best export result.

Additional Export Options

• Visio export — The SFC can also be exported to Microsoft Visio format. See Export Dialogs to Visio for details.

• Condition export on P&IDs — Conditions can also be exported directly on the P&ID drawings via the Export feature in the Module Ribbon.

📖 Workflows

How to Build an SFC for a Process

1. Open the SFC Editor — Module Ribbon → Condition panel → SFC button

2. Review the steps — All steps in the current process appear as rectangular nodes. If steps don't exist yet, create them first in Process Design

3. Arrange the steps — Drag step nodes into a logical top-to-bottom flow

4. Create transitions — Hover a step and click the Connect (↓) button, then drag to the target step. Enter the transition condition in the editor that opens

5. Add non-transition conditions — Hover a step's attached condition area and use the context menu to add Continuous Actions, Stored on Activation/Deactivation actions, etc.

6. Use Links for distant connections — If two connected steps are far apart, use the Link feature on their edge to create an off-page connector pair

7. Review the flow — Use the Phases Panel to hover steps and verify the connection pattern (orange = sources, green = targets)

8. Export — Click the PDF button to generate a printable chart

How to Navigate and Edit Conditions from the SFC

1. Hover an edge label to see the condition details and available actions

2. Click Edit to open the full Condition Editor window

3. Make your changes — they are automatically reflected in the SFC

4. Close the Condition Editor — the SFC updates immediately

How to Trace a Process Flow

1. Open the SFC Editor for your process

2. In the Phases Panel, hover over a starting step

3. The sidebar draws colored lines: orange for upstream steps, green for downstream steps

4. Follow the green lines to trace the forward path

5. Follow the orange lines to trace the backward path

6. Use Expand Previous/Next in the Module Ribbon for text-based chain navigation with condition descriptions

🏭 Pharma Example: CIP Sequence as a GRAFCET

This example shows a complete Clean-In-Place (CIP) sequence modeled as a Sequential Function Chart.

📋 Steps (Process Phases)

🔀 Transition Conditions

Non-Transition Conditions

🖱️ Keyboard and Mouse Interactions

Note: Vertex positions are saved per-process and restored when you reopen the editor. You can freely move steps and edges around — the logical connections remain unchanged.

📚 Related Pages

• Algorithm Design — Conditions and algorithm editing

• Module Ribbon — Access the SFC Editor from the Conditions panel

• Process Design — Process and step management

• Build Condition Field — Condition expression builder

• Build Action Field — Action expression builder

• 💬 Dialog — Reusable operator interaction templates

• Export Dialogs to Visio — GRAFCET Visio export details

• Valve Phase Matrix — Complementary matrix view of valve states across phases

• Symbol Editor — Symbol definition editor