Migrating Siemens OP27 ProTool Projects to Modern HMI Panels

The Siemens SIMATIC OP27 is a legacy 4-line, 20-character text operator panel that was originally configured with the ProTool software suite. When an OP27 fails in the field, the engineering question is not simply "how do I get a new one" — it is "how do I recover the project, port the visualization, and commission a replacement panel without re-engineering from scratch." This reference covers the full migration path: identifying the hardware order number, recovering a *.arh ProSave image, deciding between source-project migration and manual re-creation, converting through WinCC flexible 2008 SP2, and commissioning a modern KTP or Comfort series replacement.

1. OP27 Hardware and Lifecycle Context

The OP27 family belongs to the SIMATIC OP (Operator Panel) text-display class. Variants are ordered under the MLFB (order number) prefix 6AV3627-…, with the trailing characters encoding display color, interface type (MPI or PROFIBUS DP), and rated supply voltage. The panels communicate to SIMATIC S7-200, S7-300, and S7-400 controllers over MPI at 187.5 kbit/s or PROFIBUS DP up to 1.5 Mbit/s depending on the variant.

Before any migration step, identify the exact MLFB from the nameplate on the rear of the panel or from the engineering documentation. The order number is required to:

1. Confirm whether the product is officially discontinued and the residual-support window.
2. Select a direct-fit replacement (e.g., OP77A, OP77B) or a modern successor (TP177, KTP, Comfort).
3. Match the original panel's tag database when converting to WinCC flexible.

Refer to the official Siemens product discontinuation document for residual-support rules: SIMATIC HMI Accessories — Product Discontinuation and Total Discontinuation (PDF). A product that has been in the "Product discontinuation" phase for less than ten years can still be replaced as a like-for-like spare from Siemens. Beyond that window, only a current panel is available.

2. Prerequisites

Migration requires access to specific tooling and data. Verify the following before starting:

3. ProSave Backup File (.arh) Internals

ProSave is the Siemens utility for backing up and restoring the internal flash of an OP/TP/MP panel. The output is a single *.arh file containing:

• Compiled runtime project (firmware-loadable image, not a ProTool source).
• Recipe data and password tables at the time of backup.
• Panel firmware image for the matching panel family.
• Communication parameters (MPI address, baud rate, network profile).

ProSave restrictions to respect before any migration attempt:

1. An *.arh from an OP27 can only be restored onto an OP27. It cannot be cross-loaded to a TP177, OP77, or any Comfort/KTP panel — the firmware signature and runtime engine differ.
2. If the OP27 itself is faulty, restoring the *.arh to the same panel type is the only hardware-preserving recovery path. You need either a working donor OP27 or a Siemens repair exchange.
3. Extracting the *.arh does not yield a ProTool source project. Treat it as runtime-only.

ProSave is bundled with both WinCC flexible and (as a standalone) the SIMATIC HMI toolset on Siemens Industry Online Support. The restore operation is panel-type-locked at the firmware level — there is no engineering override to force an OP27 *.arh onto an OP77, for example.

4. Decision Tree: Source Project vs. Manual Re-Creation

Before any work is started on the replacement panel, classify the available data. The engineering effort between the two branches differs by an order of magnitude.

5. Step-by-Step Migration Path A: ProTool Source Available

5.1 Inventory the source project

1. Open the original *.pdz in the matching ProTool version (e.g., ProTool/Pro V6.0 SP2 or ProTool V6.0 SP3).
2. Export a tag list (CSV) for cross-reference against the PLC project. ProTool stores the communication driver settings — record the MPI/DP address, baud rate, and rack/slot of the connected CPU.
3. Screenshot every screen and the alarm-log configuration. These become the reference for verification after conversion.

5.2 Import into WinCC flexible 2008 SP2

1. Install SIMATIC WinCC flexible 2008 SP2. This is the last WinCC flexible release with a ProTool importer.
2. In WinCC flexible, create a new project for the target panel. Use the project wizard to select the correct panel MLFB (e.g., OP77A 6AV6641-0BA…, TP177A 6AV6642-0BA…, or a modern KTP/Comfort).
3. Use the menu Project → Migrate ProTool Project (path may vary by service pack). Point the wizard to the source *.pdz.
4. The importer maps ProTool tags, screens, and alarms to the WinCC flexible project structure. Note the converter log: review every warning — unsupported ProTool objects, scaled drivers, and area-pointer configurations are the most common items flagged.

5.3 Adapt to the target panel

1. If the target is a 4-line OP-class panel (OP77A, OP77B), the imported screens usually fit without resizing. For graphic panels (TP177, KTP, Comfort), re-layout the screens using the larger display area — text and key assignments can be retained from the imported project.
2. Re-bind the connection in WinCC flexible: the HMI's MPI/DP/PN address and the CPU's slot must match the existing PLC project.
3. Compile the project (Project → Compiler → All). Address any warnings about unsupported objects.

5.4 Optional: port to TIA Portal (WinCC)

1. For Comfort panels and modern KTP devices, the migration target is TIA Portal. Open the WinCC flexible project in TIA Portal via File → Migrate WinCC flexible project.
2. The TIA Portal migrator re-targets the project to the new panel's runtime, preserving tags, screens, alarms, and recipes where possible.
3. Recompile and download with the same TIA Portal version supported by the panel's firmware.

For TIA Portal migration details, see the Siemens entry portal: SIMATIC HMI Migration > WinCC flexible → TIA Portal.

6. Step-by-Step Migration Path B: ProSave (.arh) Only, No Source

If only the *.arh from ProSave is available, the source project cannot be reverse-engineered. The ProTool source is the only authoritative artifact for migration. In this case:

1. Recover the tag list from the PLC project. Open the STEP 7 project (S7-300/400) or Micro/WIN project (S7-200) and export all tags referenced by the HMI. These are the variables that the OP27 was reading/writing.
2. Extract operating screens from any available evidence. Use the screenshots taken from the still-functioning OP27 (if accessible), any printed HMI manuals, or the machine's electrical documentation. Each screen in the original ProTool project becomes a screen in the new WinCC flexible / TIA Portal project.
3. Re-create the visualization in WinCC flexible or TIA Portal. Re-use the tag list from step 1 and the screen reference from step 2 to rebuild the project. Map the original OP27 function keys (F1–F8 or F1–F20 depending on variant) to equivalent inputs on the new panel — either physical keys (OP77, OP77B) or softkeys (TP177, KTP, Comfort).
4. Recreate alarms and recipes. Alarm classes, message texts, and recipe structures must be rebuilt manually against the PLC data blocks they referenced. ProTool stored these in non-source binary form inside the runtime image, and they are not extractable from the *.arh in a way that round-trips into a new project.

7. Replacement Panel Selection

Choose a replacement panel based on the existing wiring, controller interface, and the desired screen footprint. The table below shows the recommended paths for the most common OP27 deployment cases.

When the controller is a SIMATIC S7-200, the new panel can be commissioned as a PROFIBUS DP slave or PROFINET IO device depending on the panel class. For S7-300/400 with MPI, the OP77A or OP77B is the closest drop-in replacement and preserves the original key numbering and screen layout, which is the lowest-risk path when the source ProTool project is unavailable.

8. Connection and Address Configuration

When commissioning the replacement panel, the connection parameters in the new project must match the bus on which the OP27 was operating. Typical MPI and PROFIBUS settings to reconcile:

Area pointers used by the OP27 (e.g., date/time, PLC job, recipe coordination, version ID) must be explicitly re-bound in the new project. ProTool stored them in the connection configuration; the imported WinCC flexible project carries them across, but in a manual re-creation they need to be re-entered against the same DB numbers in the PLC.

9. Verification and Commissioning

After the project is compiled and downloaded to the replacement panel, execute a structured verification before handing the line back to operations.

1. Tag round-trip test. For each tag in the new project, force a value in the PLC and confirm the panel updates. For each writable tag, change the value on the panel and confirm the PLC receives it. Use the tag simulation table in STEP 7 / TIA Portal.
2. Alarm test. Trigger a fault condition (e.g., simulate an input on the PLC) and confirm the alarm appears on the new panel with the correct text, class, and acknowledge behavior.
3. Recipe round-trip. If the original OP27 had recipes, write a recipe on the panel, power-cycle the panel, and confirm the recipe persists. Then trigger a recipe download from the panel to the PLC and verify the data block values.
4. Function-key mapping. For each F-key on the original OP27, verify the equivalent key on the new panel triggers the same action. On graphic panels this is typically a softkey, and the screen-level navigation should be re-tested.
5. Bus diagnostics. Use the panel's online diagnostics (WinCC flexible / TIA Portal online) and STEP 7's "Accessible Nodes" to confirm the panel is online and that the HMI-CPU connection status is green.
6. Long-duration test. Leave the panel in operation for at least one full production cycle, including shift change, alarm bursts, and recipe changes, before sign-off.

10. Troubleshooting Matrix

11. Field-Engineering Notes

• ProSave is the only hardware-level recovery path. When the OP27 is operational but the source project is lost, schedule a ProSave backup before the panel fails. The *.arh is a runtime snapshot, not a source project, but it preserves the connection configuration and the operator's current recipe data — both of which materially shorten a manual re-creation.
• WinCC flexible 2008 SP2 is the migration cap. If the source ProTool project is older (V5.x), verify that the project can be opened in the same WinCC flexible release that supports the import. Some very old ProTool projects require intermediate conversion through ProTool V6.0 SP3 first.
• Keep the PLC project authoritative. When re-creating a visualization from a ProSave-only state, the STEP 7 / TIA Portal project on the engineering PG is the canonical source of tag names, data types, and DB layouts. The panel project is a view on top of the PLC; do not treat it as the master.
• Document the bus profile. Before swapping the OP27, capture the MPI/DP address, baud rate, and any bus repeaters/terminators in the electrical drawing. A failed panel is not the time to discover the network configuration is undocumented.
• Comfort panels as the strategic target. If a long-term migration is planned (rather than a one-off repair), target a Comfort Panel or KTP from the current TIA Portal generation. The combination of PROFINET and PROFIBUS support, larger display, and the WinCC (TIA Portal) toolchain simplifies the next migration cycle.