How to Move and Copy Block Interconnections in the PCS 7 CFC Editor

In the SIMATIC PCS 7 Continuous Function Chart (CFC) editor, you can instantly transfer all existing signal interconnections from one block output to another by clicking and dragging the original output pin directly onto the target block's output pin. This single drag-and-drop operation re-routes every downstream connection simultaneously—eliminating the tedious, error-prone task of rewiring dozens of branch lines individually. Similarly, holding the Ctrl key while dragging an output pin copies the existing connection to additional input pins (multicasting), preserving existing signal lines while extending the branch to new logic.

Signal Routing Architecture in the PCS 7 CFC Editor

The CFC editor serves as the primary visual programming environment in SIMATIC PCS 7. Interconnections between Function Blocks (FBs), Functions (FCs), and shared memory addresses operate under strict graphical and topological routing rules:
- Pin Types: Every block pin has an explicit data type (e.g., BOOL, REAL, DWORD, or complex APL structures such as STRUCT: Value + ST).
- One-to-Many Fan-Out: A single block output can drive up to hundreds of downstream block inputs across different sheets and charts within the same AS CPU.
- Single-Input Exclusivity: A standard block input can only be driven by one output source at a time; connecting a new output to an occupied input replaces the previous connection unless routed through logic blocks.

Method: Transferring All Connections to a Different Block Output

When replacing an obsolete driver block, swapping sensor sources, or redirecting interlocks, moving dozens of individual connection lines manually carries a high risk of wiring omission. Use the bulk transfer workflow:

Step 1: Open the CFC Chart and Arrange Blocks

Open the target CFC chart in SIMATIC Manager.
Position the source block (currently driving downstream inputs) and the target block (the new signal source) on the same sheet or adjacent visible sheets.
Confirm that the target output pin possesses the identical data type as the source pin (e.g., both are REAL or STRUCT).

Step 2: Execute Output-to-Output Bulk Drag

Left-click and hold the output pin of the source block that currently hosts the multiple connections.
Drag the mouse cursor across the chart sheet to the output pin of the target block.
Observe the mouse cursor: it changes to a connection transfer symbol.
Release the mouse button directly over the target output pin.
Result: All connection lines that previously originated at the source pin are instantly re-routed to originate from the target pin. The source pin becomes completely disconnected.

Method: Duplicating Connections via Keyboard Shortcuts (Multicasting)

To branch a signal from an existing output to another block input without breaking established connections:
1. Identify the block output pin that is already connected to one or more blocks.
2. Press and hold the Ctrl key on your keyboard.
3. Left-click and drag from the output pin (or from an already connected input pin) to the new destination input pin.
4. Release the mouse button first, then release the Ctrl key.
5. Result: A new parallel connection branch is created while all existing connections remain intact.

Handling Cross-Sheet and Cross-Chart Interconnections

CFC automatically manages complex topology when signals span across sheets (pages 1 to 6) or cross into entirely different charts:
* Sheet Border Connectors: When a connection targets a block on another sheet or chart, CFC creates a small rectangular border connector on the margin displaying the chart name, sheet number, block name, and I/O pin.
* Rapid Navigation: Double-clicking any sheet margin reference immediately opens the partner chart and focuses the view directly on the connected block pin.
* Bulk Cross-Chart Transfer: When transferring connections via output-to-output dragging, all cross-chart links update their remote sheet border references automatically in the partner charts without requiring manual chart opening.

Verification

To ensure that interconnections have transferred correctly and signal integrity is maintained:
- Inspect the target output pin: confirm that the pin displays a solid connection line with an active branch marker indicating multiple sinks.
- In CFC, select Options -> Interconnections... or open the Chart Reference Data dialog (Options -> Reference Data -> Display).
- Filter by block name and verify that all downstream destinations now list the new block output as their signal source.
- Execute Chart -> Compile -> Changes Only: confirm compilation finishes with 0 errors and zero unintended textual interconnections.
- Switch to online Test Mode: verify that live process values and signal status bytes (ST) from the new block propagate to all recipient inputs.

Limitations and Operational Precautions

Data Type Matching Requirement: The drag-and-drop transfer only succeeds if the target output matches the data type of the source pin. Attempting to drag a BOOL output onto a REAL or STRUCT output is rejected by the editor.
Online Download Implications: Re-routing connections across charts creates modified program code. In a running plant, compile and download changes to the AS in RUN mode during stable operating conditions.
Structural Types in APL: When dealing with APL blocks, distinguish between the compound structure (e.g., PV_Out) and the elementary value member (PV_Out.Value). Dragging the root structure pin will only connect to compatible structure inputs.

Engineer FAQ

Can I transfer multiple input connections the same way?

You can re-route an input connection by dragging it from one input pin to another. However, because an input can only receive one signal, input-to-input dragging only moves that single input connection.

What should I do if the drag-and-drop operation does nothing?

Verify that you are dragging from pin to pin, not from the text label. Additionally, ensure that the chart is opened in edit mode and not in read-only / monitor-only mode.

How do I delete all connections from an output pin at once?

Right-click the output pin and select Delete Interconnection(s). A confirmation prompt will ask whether you want to delete all branches; click Yes.

Does moving connections affect the execution sequence?

The CFC editor automatically adjusts the execution order of blocks if a new data dependency is created within the same organization block (OB). Verify the run sequence in the Run Sequence Editor to ensure deterministic execution.

Technical References

Siemens Industry Online Support: SIMATIC PCS 7 CFC for S7 Manual (A5E00278782).
SIOS Entry 109742323: PCS 7 Compendium Part A - Configuration Guidelines (Section: CFC Engineering).
SIOS Entry 109809264: SIMATIC Process Control System PCS 7 Advanced Process Library Manual.
Siemens Technical Guidelines: Optimizing Engineering Productivity in SIMATIC CFC.