Understanding CFC Green Connector Tags and Sheet Bar Interconnections in SIMATIC PCS 7

In SIMATIC PCS 7 CFC (Continuous Function Chart), small green tags containing numbers attached to block inputs or outputs are automatic interconnection references called 'Connectors'. CFC automatically generates green connectors when signal lines cannot be drawn directly due to lack of sheet routing space, or when connections cross between different sheets (sheet-to-sheet) or charts (cross-chart). Each green connector displays an index number that corresponds exactly to a reference entry in the margin sheet bar showing the target block and parameter address. If so many interconnections exist that the sheet bar overflows, CFC automatically creates an 'Overflow Page'. Connectors cannot be placed manually; they are managed dynamically by the CFC layout engine.

Executive Summary

When developing and reviewing automation logic in SIMATIC PCS 7 Continuous Function Charts (CFC), engineers frequently notice small green rectangular tags containing sequential numbers (such as [1], [2], [3]) attached to block input and output terminals. These green tags replace standard solid connection lines, leading novice engineers to ask whether they can be manually inserted, moved, or deleted. In reality, green tags are an integral component of the automated CFC graphical routing engine, known formally as 'Connectors'. This article explains the layout rules governing CFC connectors, the structure of sheet bars and automatically generated overflow pages, double-click navigation techniques, and engineering practices to optimize chart readability.

Architecture and Fundamental Mechanics

CFC Graphical Routing Engine, Sheet Bar Architecture, and Overflow Mechanics:

The Role of Connectors (Green Tags) in CFC:
In SIMATIC PCS 7 CFC, every chart consists of multiple sheets (typically 6 sheets per chart by default: 2 columns x 3 rows).
When an interconnection is created between two block terminals located on the same sheet, CFC attempts to route a continuous visible graphical line.
However, when an interconnection crosses between different sheets within the same chart, crosses between different charts (cross-chart interconnections), or when local routing space is exhausted due to high block density, CFC automatically replaces the line with a Connector (a small green numbered tag).
Connectors are created, numbered, and maintained strictly by the CFC system software; they cannot be manually dragged from a library or placed onto pins.
The Sheet Bar and Reference Numbering Mechanics:
Along the left and right margins of each CFC sheet lies the Sheet Bar:
- Left Sheet Bar: Lists incoming signal references originating from other sheets or charts.
- Right Sheet Bar: Lists outgoing signal destinations routed to other sheets or charts.
When a green connector tag appears on a block terminal (e.g. green tag [4]), a matching reference numbered [4] is created in the corresponding sheet bar margin.
The sheet bar entry displays the full technological path of the interconnected partner: ChartName\BlockName.Parameter.
If a single block output fans out to multiple downstream inputs across different sheets, CFC attaches a single connector to the output line and lists all destination addresses under that reference index in the sheet bar.
Automatic Generation of Overflow Pages:
Each sheet bar margin has physical space for a finite number of text entries (typically up to 26 margin rows).
If an engineer establishes so many cross-sheet or cross-chart interconnections that the sheet bar capacity is exceeded, CFC automatically creates an Overflow Page (e.g., Sheet 1 Overflow).
An overflow page contains no logic blocks; it serves purely as an extension of the sheet bar margins, displaying additional connector address references.

Step-by-Step Implementation Procedure

Inspecting Green Connectors and Sheet Bar Mappings:
* In SIMATIC Manager, open any complex CFC chart.
* Locate a block pin displaying a small green tag with a number (e.g. [1]).
* Trace horizontally to the outer margin (left margin for inputs, right margin for outputs).
* Locate the corresponding number [1] in the Sheet Bar to read the target chart, block name, and pin.
Utilizing Interactive Double-Click Navigation:
* To instantly jump to the connected partner block, double-click directly on the green connector tag attached to the block pin.
* Alternatively, double-click on the reference text entry in the Sheet Bar.
* CFC immediately navigates to the target sheet or opens the target CFC chart and highlights the destination block and pin in red.
* To return to the originating block, double-click the green connector tag on the destination pin.
Managing and Viewing Overflow Pages:
* If a chart contains excessive interconnections, look at the sheet selection tabs at the bottom of the CFC editor.
* If an overflow page exists (e.g. labeled Sheet 2 Overflow), select it to review the extra sheet bar entries.
* Note: You cannot place function blocks onto an overflow page.
Optimizing Chart Layout to Minimize Connectors:
* While connectors maintain schematic integrity, excessive green tags degrade visual readability during runtime troubleshooting.
* To reduce connectors:
- Group technologically related blocks (e.g., channel driver Pcs7AnIn, scaling block, and monitoring block MonAnL) on the same CFC sheet.
- Use Options -> Optimize Run Sequence and arrange blocks neatly to allow direct graphical lines.
- In CFC properties, adjust chart partitioning or utilize Control Module Types (CMT) to modularize logic.

Verification

In an open CFC chart, place two blocks (And04) on Sheet 1 and one block on Sheet 2.
Draw an interconnection between the two blocks on Sheet 1: observe that a continuous solid line is drawn.
Interconnect an output from Sheet 1 to the input on Sheet 2: observe that CFC automatically inserts a green connector on both pins and generates corresponding sheet bar references.
Double-click the green connector on Sheet 1; verify that CFC transitions directly to Sheet 2 with the target pin selected.

Limitations and Operational Precautions

Connectors cannot be manually created, dragged, deleted, or reassigned by the engineer; deleting the underlying signal interconnection is the only method to remove a connector. An overflow page cannot be deleted manually; it disappears automatically only when sufficient cross-sheet interconnections are removed so that all references fit within the primary sheet bar margin.

Engineer FAQ

What are the green tags on CFC blocks called?

They are called 'Connectors' (interconnection reference tags) in SIMATIC PCS 7 CFC terminology.

Can I manually place a green connector on a pin?

No. Connectors are created automatically by the CFC layout engine when signal lines cross sheet boundaries or lack routing space.

How do I find out where a green connector leads?

Match the number in the green tag to the same number in the outer Sheet Bar margin, which lists the partner Chart\Block.Pin address.

How can I navigate to the connected block quickly?

Double-click directly on the green connector tag or on its sheet bar reference text to jump instantly to the partner block.

What is a CFC Overflow Page?

An automatically generated auxiliary page that extends the sheet bar when there are more interconnections than can fit in a single sheet's margin.

Technical References

CFC

Continuous Function Chart

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Understanding CFC Green Connector Tags and Sheet Bar Interconnections in SIMATIC PCS 7