Fixing Network Width Exceeds Page Size Warning in TIA Portal

1. Problem Description and Symptom

When editing a network in the Ladder Diagram (LAD) or Function Block Diagram (FBD) editor of Siemens TIA Portal, programmers routinely encounter the warning dialog:

The width of the network exceeds the page size set in the options.

The message surfaces specifically when:

• A new contact (normally open, normally closed) or coil is inserted into a rung whose horizontal visual extent already nears the configured page width.
• An existing network is edited and an operand box is enlarged (variable name edited, function block expanded by adding inputs).
• The project is opened on a workstation with a different DPI scaling (e.g., transferred from an engineering laptop on 4K to a desk monitor at 1080p, which changes the rendered character width).

The warning has been documented across all TIA Portal versions from V13 through V20, and it is also present in the legacy STEP 7 V5.x / SIMATIC Manager editor, where the underlying variable is labelled identically.

2. Root Cause Analysis

The LAD/FBD editor renders every network inside a virtual page. The page width is determined primarily by the Address Field Width parameter — the editor computes the pixel width of each rung by multiplying the per-character column count of every address field by the number of operands in the network. When that product exceeds the configured page size plus the page margin, the editor emits the warning.

The formula used internally (engineer-side approximation) is:

Network_Width = sum(Field_Width_i * Character_Width_px) + Page_Margin_px
              = sum(AddressFieldWidth_i) * CharWidthFactor + 2 * PageMargin

The product is rendered against the page width set in Options > Settings > PLC programming > LAD/FBD > Page size. If the sum of operand field widths exceeds the page size, the editor displays the warning before allowing the new element to be placed.

Typical triggers for the warning:

• Symbolic names that exceed the default 10-character field width.
• Use of dotted (hierarchical) symbolic names from PLC data blocks: "MyMotor".SpeedSetpoint, "Recipe".Step[3].Duration.
• Use of multi-instance DB paths: "Inst_Axis".DriveData.ActualPosition.
• Demonstration projects in which long descriptive names follow corporate naming guidelines (e.g., Conveyor_2_Motor_Overcurrent_Latched).

3. Solution: Step-by-Step Configuration

The remedy is to enlarge the Address Field Width in the editor options. The setting is per-workstation and is saved in the TIA Portal user profile (%APPDATA%\Siemens\Automation\Portal<version>\<user>\layout.xml), not in the project itself.

3.1 TIA Portal V16 and Newer

1. Close all open networks or place the editor in a stable state (Ctrl+S).
2. In the menu bar select Options > Settings...
3. In the left-hand tree expand PLC programming > LAD/FBD.
4. Locate the field labelled Width of the address field.
5. Enter a value between 10 and 26 characters.
6. (Optional) Adjust the Page size and Page orientation in the same dialog if wider rungs should still print onto a single page.
7. Click Apply, then OK.
8. Right-click inside the affected network and choose Adapt > Reset to default formatting if any element retains a manual column width.

3.2 TIA Portal V13-V15.1 and STEP 7 V5.x

1. Open the project.
2. Choose Options > Customize...
3. Select the LAD/FBD tab.
4. Modify Address Field Width between 10 and 26.
5. Click OK.
6. Re-open any network that previously emitted the warning; the new width takes effect immediately.

4. Configuration Reference Table

5. Word-Wrap Behaviour for Long Symbolic Names

The online help of the TIA Portal Information System documents the wrapping algorithm exactly:

If a name is longer than the set width of the address field, the character string is split and continued on a subsequent line ("word-wrapped") after any special characters in the name (+, -, *, /, %, =, space, ., _). If the name does not contain special characters, it is wrapped when the set width of the address field is reached.

Practical implications:

• The dot separator . in multi-instance or DB-qualified names takes precedence for breaking — "Axis_1".PositionActual wraps after Axis_1"..
• Long underscore-separated names like Conveyor_2_Overcurrent_Latched break on the underscore, producing a human-readable fragment.
• Pure lowercase alphanumeric names with no separator (verylongvariablename123) wrap only when the character limit is hit, producing an awkward fragment.

To avoid the warning altogether on extremely long names, use the I/O Shortcut technique: assign a short alias in the PLC tag table or in a global constant and let the alias take the operator slot, while the descriptive human-readable name remains in the comment field.

6. Effect on Project Compile, Download, and Runtime

The warning has no effect on the program. Specifically, it does not:

• Block the compile or build operation.
• Prevent a project download to an S7-1200, S7-1500, ET 200SP, or S7-300/400 CPU.
• Influence the online/offline comparison.
• Alter the scan time, OB1 cycle, or process image update.
• Modify the symbolic information downloaded to the CPU (this is bound to the symbol table, not the editor width).

The warning's only consequence is to constrain the visual layout of the network in the editor and the printout of the program. If the project is never printed or exported to PDF, the warning can be dismissed indefinitely — it is purely advisory.

7. Related Display Settings Worth Tuning Together

When the Address Field Width is changed, related values typically need to move in lock-step to keep networks consistent.

7.1 Reset to Default Formatting

If a network has been manually resized (drag the operand box handles), the per-element width overrides the global field width. Right-click the network and choose Format > Reset to Default Formatting. Doing so after every global change guarantees that the new width applies consistently across the project.

8. Symbolic Naming Best Practices to Minimise the Warning

The cleanest engineering remedy is to keep symbolic names short, structured, and hierarchical. The S7-1200/1500 tag syntax permits:

• Letters, digits, and underscore: Motor_Speed, Tag1.
• Integer suffixes: Motor_01.
• No leading digits: 1Motor is invalid.
• No spaces, no special characters (TIAPortal allows Umlaute but ASCII-only is recommended for portability with HMI screens and OPC UA).
• Maximum length: 128 characters (the editor displays only what fits the field width).

Recommended corporate conventions:

• Length budget: Keep symbolic names under 24 characters to fit a field width of 18 without wrapping.
• Hierarchy: Use dots for DB-qualified tags, underscores within a name: "Data".Recipe_03_Temp_SP.
• Aliases: Where the descriptive name exceeds the budget, create an alias tag in the PLC tag table pointing to the long-named DB element.
• Library storage: Inside a master copy library (TIA Portal libraries), make the source tags private and re-export them with friendly aliases when consumed.

9. Print, Documentation, and Project Handover Considerations

The warning matters most in environments where a paper or PDF archive of the program is required (plant documentation under ISO 9001 / IEC 61131-3 / GMP guidelines). For such handovers:

1. Set the page orientation to Landscape in the LAD/FBD options dialog.
2. Set the page size to A3 for archive-quality output.
3. Set the address field width to 20 so that 99 % of typical names fit without wrapping.
4. Use File > Print > Project Documentation for the rendered output rather than screen capture.
5. Enable Symbols > With Symbol Information for the export so that names remain human-readable in PDF.

If a network still does not fit after these settings, mark the network with Network Title and Network Comment, and split the logic across multiple networks using Jumps or by extracting a sub-routine into an FB/FC call — never compress symbolic names just to fit a print page.

10. Comparing TIA Portal to Other PLC Editors

The same conceptual problem exists in other vendors' editors but is solved differently.

For mixed-vendor plants, harmonising the address-field widths to the longest common name in the shared name dictionary keeps printed cross-references consistent.

11. Verification and Acceptance Procedure

After applying the new width, follow this checklist before signing off the project documentation.

1. Open the network that previously emitted the warning. Insert an additional contact of the same operand type. Verify that no warning appears.
2. Switch to Print Preview (Ctrl+Shift+M in TIA Portal) and confirm the rung fits within the configured page.
3. Perform a full project Compile > Software (rebuild all). The compile log should remain clean of warnings unrelated to the width change.
4. Perform an Online > Compare Online/Offline; the result must be identical to before the change.
5. (For F-CPU projects) Run Safety > Compile Safety Program; the F-signature must not change as a result of the display setting.
6. Open the project on a second engineering workstation; if the project is shared via TIA Portal Multiuser or via a project server, confirm the rendering matches.
7. Export the affected networks to Project Documentation PDF; archive with the configuration change recorded in the change log.

12. Frequently Asked Questions