Opening S5 .ACS Project Files: S5 to S7 Conversion Guide

Opening S5 .ACS Project Files: S5 to S7 Conversion Guide

An .ACS file is not an S5 source file, nor a backup (BKP) file, and it is not directly editable in the S5 to S7 Conversion utility. It is a compressed STEP 5 project archive produced by the S5 Archiving tool (S5-Archiv.exe). The correct workflow is: (1) de-archive the .ACS with the S5 Archiving/Dearchiving tool to recover the original *.S5D project, (2) export the blocks as *.AWL (S5 source) if a compiled binary is not available, and (3) convert the AWL with the S5 to S7 Conversion tool (S5toS7.exe) for use in STEP 7 / TIA Portal.

1. What Is an .ACS File?

STEP 5 V7.x (and earlier) ships an Archiving/Dearchiving tool that bundles a project — the binary program blocks (*.S5D), the symbol table, the assignment list, the cross-reference, and the documentation — into a single compressed file with the *.ACS extension. The container is proprietary to Siemens and is not a ZIP archive; it must be opened with the matching S5 de-archiving utility.

2. Prerequisites

Before working with legacy S5 archives, confirm the following toolchain is available on the engineering station.

• STEP 5 V7.x (V7.23 is the last released version for DOS/Windows; S5 for Windows PG is an alternative). The S5 to S7 Conversion tool expects input that matches STEP 5 V7.x semantics.
• S5 Archiving/Dearchiving tool (S5-Archiv / S5-ARC). The executable is installed with STEP 5 V7.x under C:\S5\Tools\ or distributed as arcs5.exe / s5archiv.exe.
• S5 to S7 Conversion utility (S5toS7.exe) — shipped on the STEP 7 add-on disk "S5/S7 Converter", order number 6ES7 811-1CC03-0YK0 (or successor 6ES7 811-1CC04-0YK0). Compatible with STEP 7 V5.5 and the TIA Portal import pathway.
• Target environment: STEP 7 V5.5 / V5.6 (classic) or TIA Portal V15+ with the S7 import option for legacy AWL/STL.
• Write permission to a working folder; the conversion emits several intermediate files (*.AWL, *.S7P, log).

3. Step-by-Step: From .ACS to STEP 7

Step 3.1 — Dearchive the .ACS

1. Launch the S5 Archiving/Dearchiving tool from the STEP 5 program group.
2. Select Dearchive and point it at the *.ACS file.
3. Choose an output directory; the tool extracts the *.S5D project, symbol file (*.Z0), assignment list, and SEQ/CLI files into the folder.
4. Verify the extracted set contains a file matching *ST.S5D (the standard program container). If only *.Z0 or DOC files are present, the archive was incomplete.

Step 3.2 — Open the S5D in STEP 5

1. Start STEP 5 V7.x, choose Project → Open, and select the *.S5D.
2. Browse the Blocks container; PB, FB, OB, SB, and DB blocks should be listed.
3. Right-click the program container and choose Generate Source File (or File → Generate Source) to produce a *.AWL source. The default source name is the same as the S5D stem.

Step 3.3 — Convert the AWL with the S5 to S7 Converter

1. Launch S5toS7.exe from the converter directory.
2. In the File menu, choose Open S5 File and select the *.AWL (or the *.S5D directly — the tool accepts both).
3. The Compile button (F7) runs the conversion. The lower pane lists the AWL statement by statement, with the converted S7 STL output in the right pane.
4. Save the converted output as a *.AWL suitable for STEP 7 (File → Save As).

Step 3.4 — Import into STEP 7 / TIA Portal

1. In STEP 7 V5.5/5.6: open the S7 project, navigate to S7 Program → Sources, right-click and choose Insert New Object → External Source, then Compile the imported AWL to generate the S7 blocks.
2. In TIA Portal: open the target project, choose Options → External Source → Import AWL, then compile the source container to produce FBs/FCs/DBs in the S7-300/400/1500 program.
3. Resolve any conversion warnings listed in the S5toS7 log (see Section 5).

4. Conversion Diagnostics: What the S5toS7 Tool Reports

The converter emits warnings and errors inline with the S7 STL output. The most frequent messages encountered on legacy archives include:

5. Common Error Scenarios and Root Cause

5.1 "File cannot be opened" in S5toS7

Root cause: the user opened the *.ACS directly. The converter does not parse the archive container. Run the S5 Archiving/Dearchiving tool first to obtain the *.S5D, then point the converter at the S5D or the AWL exported from it.

5.2 "No blocks listed after opening the S5D"

Root cause: STEP 5 loaded only the symbol/comment file. Verify the file selected is the program container (*ST.S5D) and not the symbol-only companion (*S0.S5D, *Z0.S5D). The S5 project name in the filename identifies the file type:

• *ST.S5D — program/blocks
• *S0.S5D — symbol table
• *Z0.S5D — assignment list
• *X0.S5D — cross-reference

5.3 Conversion produces only one FB/FC even though the AWL contains many

Root cause: the AWL was concatenated from multiple S5 source files without FB n / FC n block headers. STEP 5 AWL expects explicit FUNCTION / FUNCTION BLOCK or S5-style FB n separators. If the file was generated via "Copy All Blocks to Source" from a partial project, the block-number lines may be missing. Re-export with Edit → Generate Source on the full S5D, or insert the missing block headers.

5.4 *.ACS extracted but de-archive tool reports "CRC error"

Root cause: the archive was corrupted during transfer (FTP ASCII mode, USB write error). Re-copy the *.ACS in binary mode and try again. The S5 archiver does not tolerate bit-flip recovery.

5.5 Converter opens AWL but Compile → nothing happens

Root cause: the AWL is empty or contains only comments. Confirm with a text editor that lines such as FB 10, SEGMENT 1, and STL instructions are present.

6. Verification Checklist

1. The *.ACS de-archives into a folder containing *ST.S5D, *S0.S5D, *Z0.S5D at minimum.
2. STEP 5 V7.x opens the S5D and lists all expected blocks in the Blocks container; the block count matches the project documentation.
3. Generated AWL contains explicit block headers (FB n, FC n, DB n, OB n).
4. S5toS7 compile completes with zero "not convertible" errors for the FB/FC/DT logic; warnings about timers/counters are documented for manual review.
5. The converted AWL imports into STEP 7 V5.x and compiles to S7-300/400 blocks without unresolved symbols.
6. Cross-reference in the S7 project shows the same tag/operand count as the original S5 project (within ±5% for items the converter normalises).
7. Online test against the S7-300/400/1500 target confirms the program state transitions identically to the S5 reference (where the original hardware is still available for comparison).

7. Reference: S5 to S7 Migration Manual Excerpts

The official Siemens "SIMATIC S5 to S7 Migration" renewal manual documents the supported migration paths, the converter ordering information, and the cross-family mapping tables for operands, blocks, and organisation blocks. Engineers planning a full plant migration should consult the manual for:

• Mapping of S5 operand areas (I, Q, F, S, T, C, D) to S7 inputs/outputs/memory/timers/counters/data blocks.
• Block-type mapping: PB→FC, FB→FB (with instance DB), SB→SFC, OB→OB, DB→DB.
• Migration of the S5 standard function blocks (e.g. FB 240 integrated functions) to S7 system function blocks (SFB/SFC) or vendor libraries.
• Hardware obsolescence: S5-95U/100U/115U/135U/155U replacement matrix against S7-300/400/ET 200S.

The manual is the authoritative reference and supersedes any forum guidance: SIMATIC S5 to S7 Migration (Siemens PDF).

8. Field-Notes and Edge Cases

Symbol file with Eastern-European code page. Older *.Z0 symbol files were saved in CP850/CP852. On a Windows 10/11 engineering station the symbols appear garbled. The S5toS7 converter offers a code-page option under Options → Language; set it to the matching OEM code page before compiling.

Macros and the M5 macro library. The S5 macro library (M5) was used to bundle function blocks with parameterised names. The S5 to S7 Converter does not expand macros — it expects the macro source to be expanded before conversion. If the AWL still contains : macro identifiers, run STEP 5 → File → Expand Macros first.

DB access patterns. S5 allowed bit-level access on data words via DW n.m or D n bit syntax. S7 STL requires DBX/DBB/DBW/DBD addressing. The converter rewrites most cases, but mixed-type DB access in the same network occasionally requires manual editing.

Multiple AWL files. For large projects split across many *.AWL files, compile each individually with S5toS7, then concatenate the S7 STL outputs under a single S7 Source container before importing. The S7 importer does not accept a folder of AWL files directly.

Direct TIA Portal path. TIA Portal V15–V17 accepts legacy AWL through Options → Migrate Project → From STEP 7 or via external source import. For TIA V18+ the legacy import path was removed; route the conversion through STEP 7 V5.6 first.

9. Process Flow Diagram

10. Summary

An *.ACS file is the S5 Archiving tool's compressed container for a STEP 5 project. It cannot be opened directly by the S5 to S7 Converter, by STEP 5 itself, or by a text editor. The supported path is: de-archive → open *.S5D in STEP 5 V7.x → generate *.AWL → run the S5 to S7 Conversion tool → import the resulting S7 STL into STEP 7 V5.x or TIA Portal. Manual review of timer/counter bases, macro expansion, and S5-specific OBs is part of the standard migration effort; budget 1–2 days of review per 5,000 lines of S5 STL.

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