Siemens OP Operator Panel Overall Reset: Configuration vs Firmware Deletion Reference

The Siemens OP (Operator Panel) family — including the OP3, OP5, OP7, OP7-DP, OP15, OP17, OP25, OP27, OP35, and OP37 — predates the SIMATIC HMI Comfort/Comfort Panel lines and uses the ProTool / ProTool Lite / ProSave toolchain for project engineering, backup, restore, and firmware maintenance. One of the most common field questions during recommissioning is whether the panel's Overall Reset sequence clears only the project (screens, tags, recipes) or whether it also removes the runtime firmware image. The two outcomes are not the same, and choosing the wrong key sequence forces an unnecessary firmware download over MPI/PROFIBUS.

This reference documents the exact key combinations, what each sequence erases, how to enter Transfer mode without losing data, and the recommended recommissioning workflow using ProTool and ProSave.

1. Two Distinct Service Key Sequences on OP Panels

The Siemens OP series supports two fundamentally different on-device service procedures during the startup phase (i.e., the few seconds after power-on before the project loads). They look superficially similar because they both begin with ESC, but the resulting state of the panel is different.

2. What the Overall Reset Actually Deletes

When you hold ESC + Cursor Right + Cursor Down during the OP startup phase, the panel erases the entire Flash-resident image of the project and the operating-system runtime. After the reset, the device shows the transfer/bootloader prompt (typically "Connect to host" or a blank screen with a flashing mode LED) and refuses to start any project.

Items removed by an Overall Reset:

• Compiled ProTool project (screens, screen hierarchy, navigation logic)
• Tag / variable configuration and connection settings to the PLC (MPI node, PROFIBUS address, baud rate)
• Recipes stored in flash
• Alarm and event logs buffered in flash
• Password table for area and screen security
• The OP runtime firmware image itself

Items not affected by the reset:

• Panel hardware calibration data (contrast, touch calibration on TP variants)
• Serial number and MLFB / order number stored in the device descriptor
• Bootloader code (always retained so that ProTool / ProSave can reflash the unit)

3. Step-by-Step: Performing an Overall Reset on an OP7 / OP7-DP

Use this procedure when you need to fully recommission a panel from a known-clean state, or when the runtime image is suspected corrupt (boot loop, frozen logo, failed firmware update).

1. Disconnect the panel from its 24 V DC supply. Wait at least 5 seconds for the internal capacitance to discharge.
2. Identify the three keys on the OP7 membrane keypad: ESC, the right-arrow key (typically labeled with a right-pointing triangle), and the down-arrow key (down-pointing triangle).
3. Press and hold all three keys simultaneously. The keys must be physically held before power is applied — the OP samples the keyboard matrix at power-on.
4. While still holding the keys, re-apply the 24 V DC supply.
5. Keep the keys held until the panel transitions past the startup screen (typically 3–8 seconds). The OP will display a confirmation prompt or directly enter bootloader mode depending on the firmware revision.
6. Release the keys. The panel is now in a blank, unconfigured state.
7. Connect a PC running ProTool Lite / ProTool / ProSave via MPI or PROFIBUS (USB-to-MPI adapters such as the PC-Adapter USB A2 / 6ES7972-0CB20-0XA0 are supported) and proceed with a firmware and project transfer (see Section 7).

4. Step-by-Step: Entering Transfer Mode Without Deleting Data (ESC + Cursor Up)

This is the procedure you should use when you only need to download a new project — for example, after a project revision, after correcting a tag address, or when migrating from one PLC program version to another. The firmware is preserved; only the compiled project is overwritten by the next transfer.

1. Power down the OP.
2. Press and hold ESC and the Cursor Up key (up-pointing triangle) simultaneously.
3. Re-apply 24 V DC while continuing to hold both keys.
4. Hold the keys until the panel displays the transfer indicator — typically a message such as "Transfer mode active", a connection symbol, or a flashing COM LED depending on the OP revision.
5. Release the keys. The panel is now ready to accept a project download over MPI/PROFIBUS from ProTool or ProSave.
6. From the PC, open ProTool, choose File → Transfer → PC → OP (or in ProSave choose OP → Restore / Transfer), select the correct MPI address (default OP7 address is 1), and start the transfer.

After the transfer completes, the panel will automatically restart and load the new project. The firmware version reported in the OP's system menu remains unchanged.

5. Decision Matrix: Which Procedure to Use

6. Why the OP Doesn't Combine "Reset Project Only" with a Single Key

A common point of confusion for technicians familiar with newer SIMATIC Comfort Panels (where a project reset is a separate menu item) is that the OP series has no on-screen menu for partial reset. The hardware key sequence is the only way to trigger the wipe, and Siemens designed it as a single, intentional destructive operation paired with a separate non-destructive Transfer Mode. The choice of three keys for the destructive sequence (ESC + Right + Down) versus two keys for the non-destructive sequence (ESC + Up) is deliberate: it reduces the chance of triggering an accidental data wipe while powering the unit.

7. Recommissioning After an Overall Reset

After an Overall Reset, the panel has neither firmware nor a project. To bring it back to a working state you must perform two transfers, in this order:

1. Firmware transfer — Use Siemens ProSave (a free utility bundled with ProTool, also available separately) to flash the correct runtime image for the OP variant. Connect via MPI/PROFIBUS using a PC-Adapter (e.g., 6ES7972-0CB20-0XA0 for USB, 6ES7972-0CA23-0XA0 for legacy COM). In ProSave, select OP as the target device, browse to the .upd or .fw firmware file matching the panel (e.g., OP7-DP firmware is delivered as a ProTool component), and start the transfer. The transfer can take 5–15 minutes over MPI at 187.5 kbit/s.
2. Project transfer — Once the firmware is in place, the panel reboots and waits in transfer mode. Open the compiled ProTool project (extension .pdb / .ldf), choose File → Transfer → PC → OP, and start the download. The project transfer is typically 1–3 minutes.
3. After the project transfer, the OP automatically restarts and runs the new project. Verify by checking that the configured start screen appears and that tag communication with the PLC is active (the COM / status LED should be solid green, not flashing red).

8. Backing Up the OP Before Any Reset Procedure

Best practice is to always perform a backup of the panel's current state before triggering any reset. Use ProSave:

1. Connect to the OP via MPI/PROFIBUS from ProSave while the panel is in normal operating mode (no key sequence required).
2. Select OP → Backup and choose a destination folder on the PC.
3. ProSave will read the entire flash image (project + firmware) and store it as a .psb / .zip archive. This file can later be used in OP → Restore to return the panel to the exact previous state.

A full backup takes 5–10 minutes and is the only reliable way to recover from an incorrect Overall Reset.

9. Affected Operator Panel Models

The ESC + Cursor Right + Cursor Down Overall Reset sequence is documented for the following Siemens OP-family panels that run the ProTool runtime:

Verify the exact reset sequence for your specific MLFB against the panel's Operator Panel equipment manual before performing the operation, as some late-revision OP27/OP35/OP37 variants use slightly different startup prompts.

10. Troubleshooting Matrix

11. Field-Proven Recommendations

• Default to Transfer Mode. For 90% of field service work, ESC + Cursor Up is the correct choice. Use Overall Reset only when the runtime image itself is suspect.
• Always back up first. A ProSave backup of the OP takes under 10 minutes and is the only recovery path after an accidental Overall Reset.
• Match ProTool/ProSave versions. Mixed-version transfers are a leading cause of "transfer fails after 2 minutes" problems. Use the ProTool version that shipped with the firmware you are flashing.
• Document the MPI address. Many OPs in the field have had their MPI address changed from the default of 1. Note the address on the panel housing with a permanent marker — it will save a troubleshooting hour when the panel is next recommissioned.
• Power supply matters. The OP's power-on self-test is sensitive to supply voltage sag. Ensure the 24 V DC supply is clean and within the panel's tolerance (typically 20.4–28.8 V DC) before assuming a key sequence has failed.

12. Quick-Reference Card

SIEMENS OP SERIES — POWER-ON KEY SEQUENCES
==========================================

OVERALL RESET (deletes project + firmware):
  Hold:  ESC  +  Cursor Right  +  Cursor Down
  Apply: 24 V DC
  Wait:  10 seconds, then release
  Result: Panel blank, firmware erased, ready for
          full firmware + project re-transfer

TRANSFER MODE (preserves firmware, project overwrite):
  Hold:  ESC  +  Cursor Up
  Apply: 24 V DC
  Wait:  Until transfer prompt appears
  Result: Panel listens for project download over
          MPI/PROFIBUS from ProTool or ProSave

DEFAULT MPI ADDRESS:        1
DEFAULT MPI BAUD RATE:      187.5 kbit/s
PC-ADAPTER (USB):           6ES7972-0CB20-0XA0
PC-ADAPTER (legacy COM):    6ES7972-0CA23-0XA0