InTouch TagCreator DB Prefixes (iDB, rDB, dDB) for SimaticNet S7 Communication

Overview

Legacy InTouch HMI projects (Wonderware/AVEVA) commonly contain access names whose tag name items carry non-obvious prefixes such as iDB7.b34, rDB3.real345, dDB12.w20, DBX4.x1.0, and ddDB1.dd0. These prefixes are not native Siemens S7 mnemonics and are not generated by SimaticNet. They are produced by the InTouch TagCreator utility, a tag-import wizard shipped with older InTouch releases that converts raw PLC addresses into named InTouch tag database (DBD) entries using a configurable type-to-prefix map. The resulting tags are then served to InTouch WindowMaker/WindowViewer through OPCLink (the Wonderware OPC DA Server wrapper that bridges OPC 1.0/2.0 to the older DDE/Suitelink protocol). Understanding the prefix map is mandatory when upgrading, migrating, or troubleshooting any InTouch 7.x / 9.x / 10.x application that was authored on top of a SimaticNet OPC server.

This reference documents the prefix system, the underlying S7 addressing format, the scores7.txt resolution file, and the path to modernise the project on current AVEVA InTouch 2020 R2 / 2023 R2 with AVEVA InTouch and the AVEVA Customer Support knowledge base.

Why the Prefixes Exist

OPC DA 2.0 item identifiers are strings; they are not strongly typed. When InTouch reads a tag through OPCLink it must know whether to interpret the bytes returned by the OPC server as a signed 16-bit integer, a 32-bit IEEE-754 float, a single bit, or a BCD word. Rather than force the developer to set the data type for every imported tag manually, InTouchTagCreator applies a default prefix based on the guessed S7 data type at the source address. The prefix is then encoded into the InTouch tagname and the matching data type is assigned to the DBF record. The original raw address is preserved in the tag's Item field (or the access name's I/O address field) for the OPC server to resolve.

Because the prefix is only a labelling convention, the actual data type is bound to the tag database record in InTouch, not to the prefix string. A tag named iDB7.b34 is forced to Integer type by InTouchTagCreator, but if the developer later changes the tag's type in the DBF the OPC server will be asked to return whatever size the new type requires from the same DB offset, which usually produces a BAD quality or read of adjacent bytes.

Default Prefix to S7 Data Type Mapping

The default map installed by InTouchTagCreator matches S7 elementary data types used in data blocks (DB), inputs (I), outputs (Q), and merkers (M). The complete default map is shown below.

Decoding the Address String

After stripping the type prefix, the remainder of the tag name is the absolute byte address inside the referenced S7 area. The general form is

<prefix><Area><AreaNumber>.<DataType><ByteOffset>(.BIT)

Examples from the source project:

OPCLink and SimaticNet accept the dotted-byte form, but the canonical S7 syntax preferred by the SimaticNet OPC server is the DB<n>.DBX<byte>.<bit> form for BOOL, DB<n>.DBB<byte> for BYTE, DB<n>.DBW<byte> for WORD/INT, and DB<n>.DBD<byte> for DWORD/DINT/REAL. The starting byte offset in a Siemens data block is zero-based; offsets in some STEP 7 watch tables are one-based, which is a common source of off-by-N read errors when migrating.

The scores7.txt Resolution File

The original InTouchTagCreator emits a text-based resolution file named scores7.txt that maps each InTouch tagname to the SimaticNet OPC item path. The file is written to the InTouch project directory and to a global cache under

C:\Program Files\SIEMENS\SIMATIC.NET\opc2\binS7\scores7.txt

(the path \Program Files\SIEMENS\SIMATIC.NET\opc2\binS7 is the default install location for the SimaticNet OPC Scout / OPC server binaries on Windows; on 64-bit Windows 7/10 the path becomes C:\Program Files (x86)\SIEMENS\SIMATIC.NET\opc2\binS7 when the 32-bit-only SIMATIC NET 2008 or earlier is installed side by side with newer software).

Inspect the file with a plain text editor; entries follow the pattern

TagName=iDB7.b34   Item=S7:[S7_Connection_1]DB7,INT34
TagName=rDB3.real345 Item=S7:[S7_Connection_1]DB3,REAL345
TagName=DBX4.x1.0  Item=S7:[S7_Connection_1]DB4,BOOL1.0

The Item= value is the exact string handed to the SimaticNet OPC server; the comma-separated data type token (INT, REAL, BOOL, BYTE, WORD, DINT, DWORD, STRING) is what selects the OPC canonical data type. If you change a tag's type in InTouch without updating scores7.txt, OPCLink will still request the original canonical type and InTouch will perform an incorrect cast on the returned bytes.

OPCLink Configuration Prerequisites

1. Install the SIMATIC NET PC-Software version that matches the target Windows OS. For S7-300/400 S7-300/400 Ethernet, version 12 SP2 or later; for S7-1200/1500, version 14 SP1 or later with the TIA Portal add-on.
2. Open the Configuration Console (Start → SIMATIC → SIMATIC NET → Configuration Console). Add a new S7 Station with a logical Access Point named identically to the [S7_Connection_1] token in scores7.txt. Select the correct Ethernet interface, set the PC station's IP and the PLC's IP/TSAP or rack/slot.
3. Verify connectivity with OPC Scout V10 (or OPC Scout V20 on newer SIMATIC NET): add a new DA group, insert an item such as S7:[S7_Connection_1]DB1,INT0, and confirm a Good quality read.
4. Install OPCLink as part of the Wonderware System Platform / InTouch installation. Configure the OPCLink topic to point at the SimaticNet OPC server (ProgID OPC.SimaticNET) and select SuiteLink as the protocol to the InTouch application.
5. Re-run InTouchTagCreator against the configured OPCLink topic to regenerate the DBD with the correct prefix-to-type mapping.

Common Failure Modes

Verification Checklist

1. Open InTouch WindowMaker; load the project; choose Special → Tagname Dictionary and filter by access name. Verify that every iDB*, rDB*, dDB*, wDB*, bDB*, DBX*, ddDB* tag shows a Good quality with a plausible value.
2. Cross-check at least one tag of each prefix family against the same address in STEP 7 (online → Monitor/Modify) or in TIA Portal (online → Watch table) to confirm the byte offset is correct, especially the zero- vs. one-based convention.
3. Confirm OPC Scout can browse and read every S7 connection listed in scores7.txt. A successful OPC Scout read is a prerequisite for any InTouch visibility problem to be a configuration issue rather than a transport issue.
4. Inspect scores7.txt; the Item= strings must match the access point name, S7 connection name, and data type exactly.
5. Switch InTouch to WindowViewer runtime; toggle a single discrete tag (DBX4.x1.0) and confirm the corresponding bit in the STEP 7 VAT toggles. This round-trip proves both read and write paths.
6. Capture the OPCLink diagnostic log (SLLOGGER) and the SimaticNet trace (S7Trace.exe or SIMATIC NET Trace); ensure no 0xC0040004 / 0x80004005 errors are reported at the configured polling rate.

Migration Notes for Current AVEVA Releases

Projects using the legacy iDB*/rDB* prefix convention are still supported by AVEVA InTouch 2020 R2 and 2023 R2, but the recommended path forward replaces OPCLink + SimaticNet with the AVEVA Communication Drivers (formerly the Wonderware ArchestrA DAServer for SIMATIC Suite, now packaged as AVEVA Communication Driver for SIMATIC S7 MPI/TCP with ProgID KEPServerEX or the modern SIMATIC Suite driver). When migrating:

• Re-import the STEP 7 / TIA Portal symbol table directly into the ArchestrA or Industrial Graphic environment; the iDB/rDB prefix is dropped in favour of canonical DB<n>.BYTE<offset> addressing.
• Validate the migration with the InTouch Tag Comparison tool to detect orphan tags, type mismatches, and stale quality codes.
• Retire the 32-bit-only OPCLink DSN by moving the tag dictionary to a 64-bit ArchestrA Galaxy. The 32-bit ODBC dependency on Windows 10/11 causes intermittent hangs that look like a tag prefix issue but are actually a driver mismatch.

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