Copying Ladder Logic from SIMATIC Manager to TIA Portal via STL

Overview

Migrating Ladder (LAD) networks from SIMATIC Manager (STEP 7 V5.x) into TIA Portal (STEP 7 Basic / Professional in TIA) is a routine task when modernizing S7-300, S7-400, ET 200, or WinAC fleets. Direct copy/paste of LAD segments between the two editors is unreliable because TIA Portal distinguishes between the source CPU family and the programming-language representation of a network. The field-proven workaround is the STL Bridge Method: convert the network view to STL in SIMATIC Manager, copy the STL source text, paste it into a TIA Portal block on an S7-300 or S7-400 device, then let the TIA Portal compiler regenerate LAD/FBD. S7-1500 targets require full project migration because TIA Portal does not allow converting an existing network from STL back to LAD on 1500-series firmware.

Why a Direct LAD Copy/Paste Fails

SIMATIC Manager stores blocks as STL internally and renders LAD/FBD only as a view. TIA Portal stores the network representation explicitly per device. The following conditions break the clipboard round-trip:

• Destination CPU is S7-1500 (or ET 200SP CPU, S7-1200/1500 Software Controller). TIA Portal will accept the paste as STL but the View > LAD toggle remains disabled.
• Source block was authored against an instruction set that does not exist on the target (e.g. classic ---( SAVE ) bit logic, master-control-relay ---( MCR< ) / ---( MCRA ) pairs, or UC / CC unconditional/conditional calls without POINTER adjustment).
• Source uses accumulated local-stack L STW / T STW or direct AR1 / AR2 addressing not exposed to the LAD editor.
• Symbol table or DB interface differences cause unresolved operands that the LAD editor hides.

The STL Bridge Method

The method exploits the fact that TIA Portal's compiler on S7-300/S7-400 targets can re-synthesize LAD from STL after a successful paste. The five-step workflow is:

1. Open the source project in SIMATIC Manager with the matching STEP 7 V5.x version.
2. Open the source FB/FC/OB and switch the view from LAD to STL (View > STL).
3. Select the network(s) and press Ctrl+C.
4. In TIA Portal, open the equivalent block on an S7-300 or S7-400 device and switch to STL (View > STL).
5. Paste (Ctrl+V) into a new network, compile, then switch back to LAD.

If the destination is S7-1500, skip step 5 and keep the network as STL. You can later use Project > Migrate project to convert the whole project, then attempt an STL → LAD conversion network-by-network after the compiler validates the call hierarchy.

Prerequisites

Step-by-Step Migration Procedure

1. Prepare the source project in SIMATIC Manager

1. File > Open > User project and load the project archive (.zip) or directory.
2. Select the S7 program and run PLC > Check block consistency. Note any blocks flagged SF; fix them before export.
3. Open the symbols table (S7 Program > Symbols) and remove duplicate row entries, then Save with Symbol export disabled.
4. Compile the entire program (PLC > Compile). The result must be 0 errors, 0 warnings for a clean paste.

2. Export the symbol table for TIA Portal

1. In SIMATIC Manager: Options > Symbol Table > Export. Save as *.asc (UTF-8 / ANSI).
2. Map the export format. TIA Portal accepts ASCII format directly under Tools > Symbol table > Import.
3. Confirm that DATATYPE and COMMENT columns are populated; missing datatype entries cause TIA to flag the row as Inconsistent.

3. Build the destination project skeleton in TIA Portal

1. Start TIA Portal, Create new project > Add new device > SIMATIC S7-300 / SIMATIC S7-400.
2. Configure the rack and signal modules to match the source HW Config slot map.
3. Import the symbol table under PLC tags > Default tag table > Import (ASCII).
4. Copy DB interface stubs by hand or by SCL export/import; do not paste FBs before DB interfaces exist.

4. Paste the STL bridge

1. Open the source FB/FC in SIMATIC Manager, switch to STL.
2. Ctrl+C the networks. Verify the clipboard contains ASCII text such as

   A I 0.0
   = Q 0.0

   .
3. In TIA Portal, open the destination block on the S7-300/400 device, switch to STL view.
4. Paste into the last network and press F7 (compile block).
5. If compile succeeds, switch back to LAD. Networks that fail to render as LAD stay in STL and are flagged with the comment // LAD conversion not possible.

5. Promote to S7-1500 (optional)

1. Once all networks compile as LAD on the S7-300/400 placeholder, replace the device with the target S7-1500 CPU: Device > Change device.
2. TIA Portal applies the standard conversion rules; resolve any 16#8000_0010 diagnostics by re-mapping I/O areas.
3. Save and compile. LAD view is locked for S7-1500 blocks that contain code originating from STL-only instructions; this is expected.

CPU Compatibility Matrix

STEP 7 V5.x ↔ TIA Portal Version Matrix

Symbol and Comment Mapping

Symbols (variable names) live in the Symbol table in SIMATIC Manager and in PLC tags + DB interface in TIA Portal. The migration tool moves the global symbol table as default tag table, but instance DBs are reconstructed from the source DBs. The following behaviors are observed in production:

• DB multi-instance: TIA V13 / V14 collapsed multi-instances into single instances; V15+ restored full multi-instance support.
• Comments: Network titles migrate as block comments, but the 64-character truncation is gone in TIA — expect full multi-line descriptions to render.
• Symbolic I/O: I/O symbols of the form E 0.0 must be present in the PLC tag table; if missing, TIA falls back to absolute addressing and the LAD view hides the symbol.

Common Rework Items After Paste

1. Temporary bits (L 0.0 .. L 255.7) are local-only and reset between networks; if a network depends on a temp from the previous network, the LAD view will break because LAD cannot model stack values. Split the network or store the value in a static temp tag of the block interface.
2. Master Control Relay (MCRA / MCRD): deprecated on S7-1500 and on S7-300/400 firmware ≥ V3.3 in TIA Portal. Replace with explicit enable logic.
3. Indirect addressing via OPN DB[...] or L DBB[AR1,P#0.0] must be converted to %DB[idx].Field array indexing before LAD rendering.
4. Legacy timer / counter calls (SP T0, CU C0): replace with IEC timers/counters (TP, TON, CTU) for S7-1500 targets.
5. Bit-memory organization bytes: MB0 .. MB15 collide with S7-1500 clock/cycle bits; remap to MB20+

Hardware Configuration Migration

LAD migration without an aligned HW Config causes runtime SF and OB121 errors. The minimum HW migration steps are:

1. Use the Device > Change device wizard to map each slot; pay attention to Order number / Firmware.
2. Reassign PROFIBUS / PROFINET device names. The Topology editor must be rebuilt because GSD-based port interconnections are not preserved across the bridge.
3. Update the PG/PC interface assignment in Online > Accessible nodes so the TIA Portal can reach the rack over the same MPI/TCP path used by SIMATIC Manager.

Verification Checklist

Alternative: Full Project Migration

If more than ~30 networks need to be moved, or the program references HMI tags, the STL bridge loses its advantage. Use the integrated migration tool:

1. In TIA Portal: Project > Migrate project.
2. Browse to the .s7p / .zip archive of the STEP 7 V5.x project.
3. Select the conversion options: Copy blocks, Copy symbols, Copy HW configuration.
4. Let TIA create a Migration log; address any 16#8000_0011 entry by re-binding the listed operand.
5. After migration, run Check block consistency and resolve every entry before downloading.

The migration tool retains the LAD/FBD representation where possible. Networks that arrived via the STL bridge and stayed as STL will be flagged with // LAD conversion not possible after migration; these are the only networks requiring manual rework.

Troubleshooting Matrix

FAQ