S5 to S7 Conversion I/O Address Troubleshooting in SIMATIC Manager

When a STEP 5 program is converted to STEP 7 using the SIMATIC Manager converter (the legacy "S5 to S7" tool bundled with STEP 7 V5.x), engineers frequently report that input or output addresses shown on the original S5 wiring drawings cannot be found in the generated STL source. The most common example is a digital input block referenced as I 32.0 on the S5 schematic that appears to have disappeared from the S7 project. In almost every case the address is present; the conversion tool preserves the absolute byte/bit I/O numbering 1:1, but the block hierarchy and source file layout change enough that the engineer simply cannot locate the symbol in the converted source. This reference walks through the addressing model, the S5 PB to S7 FC mapping, and the exact search procedure used to recover a missing input address.

S5 I/O Address Format vs. S7 Address Format

Both STEP 5 and STEP 7 use the same fundamental Byte.Bit address syntax for process I/O, but the byte-numbering ranges and the peripheral word (PW) / peripheral byte (PEB/PAB) concept differ in subtle ways that cause confusion during a conversion.

Critical point: when an S5 program is converted, the converter does not renumber the I/O bytes. I 32.0 in the original S5 source remains I 32.0 in the converted S7 source. The discrepancy is structural, not numerical.

Why an S5 Address Like I 32.0 Appears "Missing" After Conversion

The reported symptom — "I 32.0 is on the drawing but I cannot find it anywhere in the STL" — has three recurring causes, ordered by frequency in field service reports:

1. Block hierarchy reorganized. S5 program blocks (PB 1 through PB 255) are converted to S7 functions (FC 0 through FC 255 by default, configurable in the converter options). The I/O operations are intact, but they now live inside an FC the engineer did not open. A drawing that referenced I 32.0 inside "PB 14" on the original machine now lives inside "FC 47" (or whichever FC number the converter assigned).
2. Source view filtered by symbol table. When the converted project is opened with absolute operands hidden behind symbolic names, the literal I 32.0 does not appear in the source view. Searching the symbol table for "I32.0" returns nothing because the symbol table entries point to addresses that the converter did not generate.
3. Conversion aborted on a different PB. If the converter emitted an error or warning on PB 14, only the successfully converted blocks were written to the S7 project. The engineer sees a partial project and assumes I 32.0 was lost.

S5 Program Block (PB) to S7 Function (FC) Mapping

The STEP 5 to STEP 7 converter applies a deterministic mapping for code blocks, with user-selectable offsets under Options > S5 Conversion > Block Numbers.

Reported case: PB 14 from the S5 source converted to FC 47. This is the result of either an automatic offset (PB 14 + 33) or a manual block-number reassignment chosen in the converter options. The block numbering rule can be verified by reading the converter log file S5toS7.log in the project directory.

Locating I 32.0 in the Converted STL Source

Use the following procedure in SIMATIC Manager (STEP 7 V5.5 or V5.6) to recover any absolute input or output address that appears to have vanished after conversion:

1. Open the converted project and select the S7 Program container.
2. Right-click the Blocks folder and choose Object Properties > Operand Overview to dump the cross-reference, or open the cross-reference list with Options > Reference Data > Display.
3. In the cross-reference window, filter by operand I 32. The list shows every FC, FB, OB, and DB that references inputs in byte 32.
4. If the cross-reference is empty, the conversion log S5toS7.log will list every PB that emitted a warning or error. Open the relevant PB in the source .S5D backup and re-run the converter on that PB alone.
5. Once the holding FC is identified (e.g. FC 47), double-click it to open the STL editor and use Ctrl+F to search for the literal string I 32.0.

Concrete STL excerpt recovered from a converted project, demonstrating that I 32.0-class operands survive the conversion unchanged:

      A   I 32.3;
      O   I 32.4;
      O   I 32.6;
      A   M 104.0;
      =   Q 48.5;

Every operand in this segment is bit-exact with the original S5 source. The A (AND), O (OR), and = (assign) mnemonics are identical between STL/AWL in the two environments; STEP 7 also accepts the German AWL form U, O, = interchangeably.

Common Conversion Warnings and Their Meaning

The STEP 5 to STEP 7 converter produces a structured log. The entries most relevant to I/O addressing are listed below with their typical root cause.

Step-by-Step Verification Procedure

Once the converted project loads to the S7 CPU without errors, perform the following verification sequence before accepting the conversion as equivalent to the original S5 behavior.

1. Block inventory cross-check. Open the S5 backup in STEP 5 > S5-DOS or the S5 for Windows tool and export the PB/FB/DB list. Compare it to the S7 Blocks folder; every block should have a 1:1 counterpart (PB x to FC x + offset).
2. Operand coverage check. Use Options > Reference Data > Display > Cross-references and filter by operand class I, Q, M, PIB, PQB. Every operand referenced on the S5 drawings must appear at least once.
3. Process image size. Open HW Config, select the CPU, and verify the Process Image tab. The I-area start and end must cover the highest referenced input byte; the Q-area must cover the highest referenced output byte.
4. Symbol table import. Convert the S5 symbol table (Z0.SEQ or SYMBOL.S5D) via Options > Symbol Table > Import. Resolve any W1022 warnings manually.
5. Online I/O force test. Connect to the CPU with PG online, open the FC that contains the suspect address (e.g. FC 47), and use Debug > Monitor/Modify to toggle the physical input. The bit must transition in the process image (I 32.0 from 0 to 1 when the field contact closes).
6. OB1 scan time. Compare the OB1 execution time before and after conversion; a 5x increase indicates the converter inserted interpreted STL where direct S7 code should be used. Rewrite the hot path manually in STL.

Cross-Referencing I/O in SIMATIC Manager

For routine cross-referencing of an operand such as I 32.0 across the entire converted project:

• Go To > Location (Ctrl+Alt+Q) from any STL network containing I 32.0 jumps to every other occurrence across all loaded blocks.
• Reference Data > Program Structure shows the call hierarchy from OB1 down to the FC that owns the operand.
• Symbol table search by address (right-click > Filter > Address = I 32.0) is the fastest way to map an S5 drawing symbol to its converted location.
• PLC > Compare Blocks against the original S5 source via the offline/online diff function confirms structural equivalence.

Conversion Issue Matrix

Pre-Conversion Documentation Checklist

Before running the converter, capture the following from the S5 source so that post-conversion verification can be performed systematically:

• Full S5 program backup file (.S5D) with all PBs, FBs, SBs, DBs, OBs, and FXs.
• Symbol table export from the S5 PG, ideally as a CSV.
• Hardware configuration document: CPU type, I/O rack assignments, and the byte/bit-to-terminal mapping for every input and output card.
• Process image size used by the S5 CPU (commonly 128 bytes, but can be 256 on S5-155U).
• List of any S5 special functions (e.g. SU, RU, TB, TF) that are not in the STEP 7 operation set.
• The desired block-number offset for the converted FCs, if the default 1:1 mapping collides with existing blocks in the target S7 project.

With this material in hand, the post-conversion "missing address" investigation reduces to a single cross-reference filter, as described in the procedure above. The reported field case — where the engineer could not initially locate I 32.0 — closed as a self-resolved user error once the correct converted FC was opened and searched.

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