Resolving TP177B WinCC Flexible Version Mismatch and ALM Error

Problem Overview

The SIMATIC TP 177B and OP 177B are 4-inch and 6-inch color touch panels based on Windows CE. They integrate into SIMATIC S7-200, S7-300/400, and SINUMERIK architectures via PROFINET, PROFIBUS, or MPI. A recurring field problem arises when a project archive created in one version of WinCC flexible is loaded onto a panel whose runtime image does not match the WinCC flexible version on the programming station. The symptom is a hard download failure with the panel reporting that the project image version does not match its own runtime image version.

A second, related failure is encountered when an engineer attempts to back up licenses from the panel prior to performing an OS update/downgrade: the Automation License Manager (ALM) returns a low-level connection error (Connection Error: 16842752) when attempting to attach over Ethernet, and the only reliable workaround requires switching to a PROFIBUS/MPI connection with a PROFIBUS dongle.

This article documents both failure modes, the exact image-version mapping for the TP 177B and OP 177B family, and the field-proven recovery sequence using a PROFIBUS-based ALM attach followed by an OS downgrade of the panel image.

Affected Products, Catalog Numbers, and Image Versions

The TP 177B 4-inch (6AV6 642-0AA11-0AX1) and the TP 177B 6-inch color PN/DP (6AV6 642-0BA11-0AX1) as well as the OP 177B 6-inch (6AV6 642-0DC01-0AX1) all share the same WinCC flexible image family. The image file naming follows the convention Mobile_OP_TP177B_V<major>_<minor>_<build>_<revision>.img.

The original delivery release notes for the TP 177B / OP 177B confirm that the initial firmware at product launch did not support PROFINET / IO direct keys and required WinCC flexible 2005 SP1 as the minimum authoring tool, per the SIMATIC TP 177B and OP 177B Delivery Release (Siemens ID 21779155).

Symptom Matrix

Root Cause Analysis: Why the Version Check Fails

The TP 177B bootloader stores a build identifier in the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Siemens\HMI\ImageVersion. During a project transfer, the authoring tool's Transfersettings dialog embeds a checksum that must match the panel's stored image revision. WinCC flexible 2005 SP1 HF7 generates checksums against the V1_0_1_7 runtime API set; V1_1_1_0 panels were built against the WinCC flexible 2008 image API, which expanded the protocol, added improved PROFINET IO direct key handling, and changed the project manifest format.

The mismatch is therefore not a corrupted transfer — it is a hard version downgrade protection added to prevent partially-supported projects from bricking the panel. The same mechanism prevents you from loading a 2008 project into a 2005 SP1 panel unless the panel image is first aligned with the authoring tool.

Root Cause Analysis: ALM Error 16842752

The Automation License Manager (ALM) communicates with the panel over a vendor-specific transport layer that piggybacks on the ProSave / WinCC flexible Transfer channel. Error code 16842752 is a packed Win32 status field. Decoded:

• Low word (0x0000): S_OK initial state
• Status code: 0x01010000 = ALM_E_TRANSFER_NEGOTIATE_FAILED — the panel rejected the ALM transfer-init frame because the ALM transport on the engineering PC could not negotiate a compatible session over TCP/UDP on the panel's port.

Root causes seen in the field:

1. Windows Firewall on the engineering station blocking ALM's almsrv.exe on TCP 4410 (primary) and UDP 4410 (discovery).
2. ALM service not started (services.msc → "Automation License Manager").
3. Panel Ethernet not bound to the ALM transport — common on V1_1_1_0 panels when PROFINET is enabled and PROFINET IO controller mode locks the Ethernet interface to PROFINET-only traffic.
4. Crossover cable mis-wired or panel not configured to allow remote ALM attach in Start → Settings → OP → Transfer → Enable Remote Control.

Prerequisites for the Recovery Procedure

• ProSave installed (bundled with WinCC flexible or available standalone on the Siemens support site).
• Original panel image file matching the desired target WinCC flexible version (e.g., Mobile_OP_TP177B_V1_0_1_7.img for a 2005 SP1 HF7 authoring station). Extract from the WinCC flexible installation DVD under \Support\Images\TP177B\ or download from the Siemens Product Support portal.
• PROFIBUS PC-Adapter: USB PC-Adapter (6ES7 972-0CB20-0XA0) or legacy COM PC-Adapter (6ES7 972-0CA23-0XA0). A CP 5512 (6GK1 551-2AA00) or CP 5611 (6GK1 561-1AA00) PCI card also works.
• License dongle / license key for the matching WinCC flexible version, or an existing panel-side license to be transferred.
• Ethernet crossover cable for the WinCC flexible project transfer (post-downgrade).
• Engineering station with WinCC flexible 2005 SP1 HF7 (or whichever version matches the target image) installed and licensed.

Procedure: Backing Up Panel Licenses via PROFIBUS

1. Connect the PC-Adapter USB to the engineering station. Install the SIMATIC PC-Adapter USB driver; confirm the COM port assignment in Device Manager (e.g., COM4).
2. Set the PC-Adapter DIP switches: MPI mode (1=on, 2=off for PC-Adapter USB V2) and the panel's MPI address (factory default 1, baud 187.5 kbps).
3. Connect the PROFIBUS/MPI cable to the panel's MPI/DP port and to the PC-Adapter.
4. On the engineering station, open Automation License Manager (Start → Siemens Automation → Automation License Manager).
5. In ALM, navigate Edit → Connect to Target System → Connect.
6. Select Panel / PC connection (S7MPI / PROFIBUS) and the COM port assigned in step 1.
7. Set the panel's MPI/PROFIBUS address (default 1) and baud rate (187.5 kbps for MPI).
8. Click Connect. ALM should attach without raising 16842752, because the PROFIBUS transport is not blocked by PROFINET or Windows Firewall.
9. Once attached, the ALM tree shows the panel's local license storage under Panel → Local Licenses. Right-click each license and select Backup License to a secure *.lic file on the engineering station. Store the file in a versioned directory (e.g., D:\Licenses\TP177B_SerialNo_20240115\).
10. Repeat for every license present on the panel. ALM does not always list all licenses in a single attach; cycle the panel's transfer enable, wait 15 seconds, and reconnect if any expected license is missing.

Procedure: OS Downgrade of the TP 177B Panel

1. Open ProSave on the engineering station.
2. Select device type TP 177B 6" color PN/DP (or 4" / OP 177B 6" mono as applicable).
3. Set connection type to PROFIBUS / MPI and configure the COM port to match the PC-Adapter.
4. Set the panel's MPI/PROFIBUS address (default 1) and baud (187.5 kbps).
5. Click OS Update in the left navigation pane.
6. Browse to the target image file. For the original 2005 SP1 HF7 authoring station, select Mobile_OP_TP177B_V1_0_1_7.img.
7. Check Perform Reset to Factory Defaults after update if the panel previously held projects that should be cleared.
8. Power-cycle the panel if prompted. ProSave pushes the bootloader update first, then the runtime image. The panel displays a Siemens logo and a progress bar.
9. Total transfer time: 4 to 8 minutes for a TP 177B 6" over PROFIBUS at 1.5 Mbps; do not interrupt power during the flash window (last 60 seconds).
10. When ProSave reports OS Update Completed, the panel reboots. Verify the new image version on the panel by navigating to Start → Settings → Control Panel → OP → OS Update and reading the displayed build string.

Procedure: Restoring Licenses and Loading the Project

1. After confirming the new image version, open ALM and Edit → Connect to Target System → PROFIBUS.
2. Right-click Panel → Local Licenses → Restore License for each *.lic file backed up in the prior step.
3. Close ALM.
4. Open WinCC flexible 2005 SP1 HF7 and load the project archive.
5. Set the transfer mode in WinCC flexible to PROFIBUS / MPI or switch to Ethernet crossover as required.
6. Press the panel's transfer button (or enable Remote Control via Start → Settings → Transfer).
7. Click Transfer → PC -> Panel in WinCC flexible. The panel will accept the project because the authoring tool and the runtime image now share the V1_0_1_7 image family.

Verification Steps

1. Confirm the panel's image version: Start → Settings → Control Panel → OP → OS Update → Version. The string must match the authoring tool's expected image family exactly.
2. Confirm the project loaded cleanly. On the panel desktop, the project name appears in Start → Settings → Control Panel → OP → Project Information.
3. Confirm the panel boots into the project at power-on without re-prompting for a transfer.
4. Validate each licensed feature (e.g., number of tags, Sm@rtAccess, Sm@rtService) by opening the project in the panel's runtime and confirming the feature is enabled.
5. Smoke-test the PLC connection: cycle power, verify the HMI comes up and tags refresh. For PROFINET, verify the panel is visible in the PROFINET topology editor of STEP 7 / TIA Portal as expected.

Alternative: Upgrading the Authoring Station Instead of Downgrading the Panel

If the panel is V1_1_1_0 and the project was originally authored in 2005 SP1 HF7, the operator may have performed the upgrade. In that case, the engineering path is to upgrade the WinCC flexible authoring tool rather than downgrade the panel:

1. Install WinCC flexible 2008 (or 2008 SP1) on the engineering station, matching the panel's V1_1_1_0 image family.
2. Open the original *.hmi or *.zip archive. WinCC flexible performs an automatic project migration; some custom C-scripts and the older ProTool-style tag import map must be re-checked.
3. Re-compile, then transfer via Ethernet or PROFIBUS.

The decision to upgrade the tool vs. downgrade the panel should be based on: panel warranty status, fleet standardization, license key availability for the newer WinCC flexible version, and whether the rest of the plant runs on the older or newer image family.

Edge Cases and Field Notes

• Empty ALM tree after PROFIBUS attach. On panels that were upgraded from V1_0_1_7 to V1_1_1_0 by a third party, the internal license storage sometimes re-formats and shows zero entries to ALM. In this case, licenses were already invalidated by the upgrade, and the only recovery is to apply fresh license keys to the panel using ALM's Transfer License to Target System.
• ProSave "Timeout" over PROFIBUS. Lower the baud rate to 187.5 kbps if the PC-Adapter is set to 1.5 Mbps and the bus segment is long. The TP 177B's MPI port internally terminates at 187.5 kbps for the default address 1.
• Panel stuck in bootloader after a failed image transfer. Use ProSave's Reset to Factory Defaults and re-transfer the image. The bootloader is read-only, but the runtime partition is not — it can be reflashed repeatedly.
• Mixing WinCC flexible Compact and Standard editions. The image family is the same on the panel, but the licensing differs. Compact cannot be used to author projects intended for Standard-only features (e.g., audit trail, Sm@rtService). Mismatched edition produces a different version error than the V1_0_1_7 vs. V1_1_1_0 case described in this article.
• TP 177B 4" mono vs. color image files share the same name pattern; confirm you are flashing the correct 4" variant by reading the panel's MLFB before invoking ProSave. Flashing a 6" image to a 4" panel bricks the display subsystem until a correct image is reflashed.

Troubleshooting Matrix

FAQ