Resolving STEP 7 V5.5 to TIA Portal V11 Conversion Error

Problem Overview

Migrating a SIMATIC STEP 7 V5.5 project targeting an S7-300 CPU to TIA Portal V11 (STEP 7 V11 SPx) frequently aborts during the conversion phase with a generic error dialog that does not name the offending object. The migration wizard terminates before any blocks, symbols, or hardware configuration reach the TIA project tree, leaving the operator with no migrated artifacts and no actionable log entry beyond the JPG-captured screenshot.

This failure pattern is well documented on the Siemens support portal and is not unique to a single block type. The conversion error appears when the STEP 7 V5.5 source contains either:

• UDT (User-Defined Data Type) components or symbol names that use characters outside the A-Z, a-z, 0-9, hyphen (-), and underscore (_) sets permitted by the TIA Portal V11 compiler.
• Project metadata in a non-English language locale that produces character-set or translation mismatches against the V11 migration converter's string parser.

The diagnostic symptom is identical in both cases: the migration wizard displays an unrecoverable error and rolls back the partial conversion.

Root Cause Analysis

The TIA Portal V11 migration path from STEP 7 V5.x implements a strict naming validator that re-checks every identifier carried over from the legacy project. Two specific rules trip the converter:

1. Identifier Character Set Restriction

STEP 7 V5.5 accepts a wider range of characters in UDT member names, symbol names, and comment text because the underlying editor is loosely typed. TIA Portal V11 enforces a tighter subset aligned with IEC 61131-3 identifier rules. Any component that contains accented characters, spaces, special punctuation (e.g. /, \, ., :, parentheses), or non-Latin script raises a converter-level exception that aborts the migration.

2. Project Locale and Translation Tables

When the STEP 7 V5.5 source project was created or last saved under a non-English Windows locale (for example Italian, German, French, Spanish), the embedded translation strings and project metadata use code pages that the V11 converter cannot map consistently. The converter fails on the first UDT or block whose display name contains a locale-specific character sequence.

Supported Migration Baseline

Before applying any workaround, confirm the source version falls within the migration envelope supported by the installed TIA Portal. The Siemens engineering knowledge base states:

Reference: Migration of STEP 7 projects (S7-300, S7-400) - TIA Portal

Reference: What are the requirements for the migration of STEP 7 V5.x projects in STEP 7 (TIA Portal)?

Pre-Migration Prerequisites

1. Open the source project in SIMATIC Manager (STEP 7 V5.5) on a workstation where the operating system locale matches the project locale.
2. Verify the project compiles cleanly in STEP 7 V5.5 with no warnings (menu PLC > Compile and Download Objects). A clean baseline reduces ambiguity when the converter emits an error.
3. Create a full project archive (.zip) before any modification so the original can be restored if a workaround introduces regression.
4. Install TIA Portal V11 with the latest Service Pack available for that major version (SP5 or later where licensing permits). Early V11 SPs are known to be more sensitive to locale-specific character handling.
5. Confirm the target TIA Portal installation includes the optional STEP 7 V5.5 migration tool package and the S7-300 hardware support package.

Naming Convention Constraints

Apply the following rules to every identifier the migration converter will inspect. The list mirrors the IEC 61131-3 identifier grammar enforced by the TIA Portal V11 compiler and the legacy migration bridge.

Language Handling Workaround

If the source project was authored in a non-English locale and renaming every offending identifier still produces the same converter error, switch the working language to English before the migration attempt:

1. In SIMATIC Manager, open the source project.
2. Select menu Options > Language for Display Devices and verify the active language pack.
3. Select menu Options > Settings > Language and switch the Mnemonics and Project language to English (USA).
4. Save the project. This forces a rewrite of the project header and translation cache with English-only metadata.
5. Re-run the migration to TIA Portal V11.
6. After the migration succeeds, switch the TIA Portal project language back to the original locale if required by the end user.

Step-by-Step Migration Procedure

The procedure below combines the identifier rename workaround and the language workaround into a single field-proven workflow. It is designed to be reversible so the legacy program logic is preserved exactly.

Step 1 — Archive the Original

In SIMATIC Manager:

1. Select the project root.
2. Menu File > Archive, choose *.zip (with S7 subdirectory structure), enable With reorganization.
3. Save the archive to a network share with a timestamp filename, e.g. ProjectA_2024-05-21_preV11migration.zip.

Step 2 — Locate Offending Identifiers

1. Menu Options > Cross-References and search for each UDT, FB, FC, DB, I/O symbol, and tag whose name contains characters outside the allowed set.
2. For each match, record the original name in a side log so the rename can be reversed after migration.
3. Repeat the search inside every UDT component (right-click the UDT, Open, inspect Components tab). The migration converter validates component names with the same strict grammar.

Step 3 — Apply Temporary Rename

1. Rename each offending identifier to an ASCII-only alias (for example Stato_Valvola → Stato_Valvola if accented; spaces → _; periods → _).
2. Update all cross-references automatically: SIMATIC Manager offers Check Block Consistency and Rewire to update call sites after rename.
3. Compile the project (PLC > Compile and Download Objects) and resolve every warning. A clean compile is a prerequisite for migration.

Step 4 — Run Migration to TIA Portal V11

1. Launch TIA Portal V11 (latest SP installed).
2. Menu Project > Migrate project.
3. Browse to the renamed STEP 7 V5.5 project file (*.s7p or archived *.zip).
4. Select target storage location and confirm migration. The converter should now complete without the previous error.

Step 5 — Restore Original Names in TIA Portal

1. Open the migrated project in TIA Portal V11.
2. Right-click each renamed UDT/FB/FC/DB/tag, choose Rename, restore the original identifier from the side log.
3. For UDT component names, open the UDT editor and restore each component name individually.
4. Recompile the project (Compile > Software (rebuild all)). Resolve any compilation warnings before continuing.

Step 6 — Final Verification

See the verification section below for the complete checklist.

Verification

After migration and the post-migration rename, validate that no semantic drift was introduced:

1. Compile check: Compile > Software (rebuild all) must complete with zero errors and zero warnings.
2. Cross-reference parity: Open the original STEP 7 V5.5 project side by side and compare the cross-reference report count for the renamed UDT/blocks. Counts must match before and after migration.
3. Online comparison (with HW available): Go online with the S7-300 CPU and perform Compare > Online/offline for every block. The status must report Identical.
4. Symbol table integrity: Open PLC tags in TIA Portal. Every symbol that was renamed back to its original spelling must resolve to the correct address and data type.
5. UDT instance consistency: Open each multi-instance DB and confirm the nested UDT layout matches the STEP 7 V5.5 source. Any structural mismatch here indicates an incomplete rename.
6. Hardware configuration: Open Devices & Networks and confirm the S7-300 rack, signal modules (SM), function modules (FM), and communication processors (CP) appear with the correct order numbers and firmware versions.
7. Connection data: For projects with NetPro connections (S7 connections, ISO-on-TCP, TCP, UDP), open Devices & Networks > Connections and verify each partner IP, port, TSAP, and rack/slot combination.

Error Code and Symptom Reference

Troubleshooting Matrix

Safety and Operational Notes

Long-Term Recommendation: Target a Newer TIA Portal Version

The TIA Portal V11 migration path is the earliest bridge from STEP 7 V5.x and contains the sharpest identifier and locale restrictions. Newer TIA Portal versions (V13, V15.1, V16, V17, V18, V19, V20) include expanded Hardware Support Packages, improved legacy block coverage, and a more tolerant migration converter. Where licensing and project scope allow, plan an upgrade path that migrates first to V11 (for proof of concept) and then to a current TIA Portal release for production support. The official Siemens migration documentation explicitly references this staged approach for S7-300/S7-400 source projects.