Siemens TP1900 Comfort V2 Touch Calibration Failure: OS Recovery

1. Problem Description

Operators commissioning a SIMATIC HMI TP1900 Comfort V2 panel (MLFB 6AV2124-0UC02-0AX1) running WinCC Comfort image V15.01.00.02_04.01 report that the touch input registers only inside a sub-region of the active screen. The display remains responsive to finger or stylus contact, but the pointer's effective area is visibly smaller than the LCD. The pointer is typically compressed toward the upper-left or upper-right corner, leaving large dead bands along the bottom and right edges.

When the operator enters the HMI control panel and starts a touch calibration (2×2, 3×3, or 5×5 reference points), the routine reaches the final target crosshair, captures the touch event, and aborts with the on-screen prompt:

Touch Calibration was not successful, please repeat if necessary

The new calibration constants are not written to flash. The panel either returns to the control panel or reboots with the previous (defective) calibration, so the same offset persists after every restart. Re-running the calibration in 2×2, 3×3, and 5×5 mode produces identical results; the time-budget of the routine is exhausted before the final point is accepted.

A second symptom is reported when the engineer attempts to reflash the OS image with Siemens ProSave. The transfer dialog fails with:

Downloading is not possible. The connected device type does not match the default device type

Both symptoms co-occur on panels that have just had the touch foil replaced, were force-flashed with an incompatible OS image, or were restored from a project archive without a clean OS load. The combination of a freshly replaced touch surface and a V2-second-generation panel is the most common trigger in field reports.

2. Affected Hardware and Firmware Matrix

3. Root Cause Analysis

Three independent root causes are documented in field reports on the TP1900 Comfort V2. They can occur alone or stacked.

3.1 Calibration Time Budget Exceeded

The WinCC Comfort calibration routine expects each reference touch to be held for at least the minimum dwell time and the entire sequence to be completed within an internal time budget. If the user hesitates at any crosshair, lifts the stylus, or the touch controller does not register a stable contact on the new foil, the final point is rejected and the new constants are discarded. The previous (defective) calibration is left in non-volatile storage.

After a touch-foil replacement, the analog resistive controller on the new foil may have a higher activation force, a slightly different sheet resistance, or a marginally different bezel-to-Active-Area alignment. The default calibration time budget, tuned for the factory foil, is then insufficient. The operator reads the "not successful" message as a user error when it is actually a touch-controller parameter mismatch.

3.2 OS Image Built for the Wrong Device Class

ProSave validates the connected panel against the image catalog before allowing the download. If the engineer feeds a Unified Comfort image, a V1 image, or a generic "TP1900" catalog entry that does not include the V2 hardware ID, ProSave aborts with the "device type does not match the default device type" error. The image stays on the engineering station and the panel keeps its previous runtime.

Common mis-selections observed in the field:

• Selecting the Unified Comfort catalog when the panel is a Comfort (V2). The catalog entries share the screen size and family prefix but are not interchangeable.
• Selecting a V13 image for a V2 panel. The V2 hardware requires V14 SP1 or higher in the project; loading a V13 image leaves the panel in a non-bootable or partially initialized state.
• Selecting the V2 catalog but pointing ProSave at a sub-variant that lacks the matching MLFB suffix (e.g., a TP1900 Comfort PRO variant vs the standard).

3.3 Stale Calibration Constants After Touch-Foil Replacement

When the touch foil is replaced, the panel hardware does not automatically re-detect the new analog characteristics. The calibration constants stored in the registry under the touch-driver key are tied to the previous foil. A factory reset (or an OS update with the "Reset to factory settings" option) is required to clear the constants and force the driver to re-initialize against the new foil.

4. Diagnostic Procedure

Run the following checks in order before attempting any reflash. Each step takes less than five minutes and prevents unnecessary image transfers.

1. Confirm the panel's exact MLFB on the rating plate. For the V2, the part number starts with 6AV2124-0UC02-. The V1 starts with 6AV2124-0MC02-. They are not interchangeable.
2. Boot the panel to the Control Panel (Start → Settings → Control Panel → OP) and read the OS image version. It must match a V14 SP1, V15, V15.1, V16, or V17 image. A V13 or earlier image on a V2 panel is a mismatch.
3. From the same OP dialog, read the device name and the runtime version. Record them for the ProSave target configuration.
4. Connect the engineering station to the panel via Ethernet (recommended) or USB. Set the panel's transfer channel in the Control Panel (Transfer → Ethernet / USB). Note the panel IP address; the default is 192.168.0.1 with subnet 255.255.255.0 if the panel is in factory state.
5. Open ProSave on the engineering station. From the General tab, set:
   • Device type: TP1900 Comfort V2 (or the exact catalog entry for the V2 hardware)
   • Connection: Ethernet (or USB)
   • Target IP / USB node: as recorded in step 4
6. Click Device status (or Accessible nodes). The panel must reply with its catalog name and OS image version. If ProSave reports an unknown device, the catalog on the engineering station is missing the V2 HSP.
7. From the OS Update tab, browse to the .img file. The path is typically:
   • V15: C:\Program Files\Siemens\Automation\Portal V14 SP1\Data\Hmi\Transfer\15.0\HmiTP1900_Comfort_V2_V15.0.img
   • V15.1: C:\Program Files\Siemens\Automation\Portal V15.1\Data\Hmi\Transfer\15.1\HmiTP1900_Comfort_V2_V15.1.img
   • V16: C:\Program Files\Siemens\Automation\Portal V16\Data\Hmi\Transfer\16.0\HmiTP1900_Comfort_V2_V16.0.img
8. Confirm the image is the Comfort (not Unified Comfort) variant. The file size of a Comfort V2 image is roughly 220–260 MB; a Unified Comfort image is significantly larger and starts with a different catalog header.

If the panel does not boot to the Control Panel because the touch is too far off, fall back to the external keyboard + mouse path. Plug a USB mouse into the panel's USB-A port; the runtime will accept mouse events even when touch is mis-calibrated and you can navigate to the OP dialog.

5. Step-by-Step: Recalibration Within the Time Budget

Use this procedure when the touch responds but the calibration routine aborts. It targets the timing constraint in section 3.1 without requiring an OS reflash.

1. Plug a USB mouse into the panel and open Start → Settings → Control Panel → OP with the mouse.
2. Open the Touch tab. Select Calibrate Touch Screen.
3. Choose the 5×5 reference pattern. Five points per row gives the analog resistive driver the most data to recompute the linearization matrix; 2×2 leaves large interpolation errors that exaggerate the offset seen on a new foil.
4. Set a stopwatch for 20 seconds. The full sequence must complete in under 20 s; a normal hand completes it in 8–12 s.
5. Touch the first crosshair and hold for at least 1 s. Release only when the driver registers the contact (the crosshair jumps to the next position).
6. Maintain a consistent stylus angle. Holding the stylus at a steep angle during the first and last points shifts the resistive contact centroid and is the most common reason for the final-point rejection.
7. On the final crosshair, hold the contact for at least 2 s. If the panel does not advance within 3 s, release, wait 2 s, and re-touch. Do not hold continuously past 5 s; the driver will time out and discard the entire sequence.
8. If "Touch Calibration was not successful" reappears, repeat the sequence three more times. The driver keeps the most recent successful partial calibration even when it aborts, and successive runs typically improve the linearization.
9. If three consecutive attempts fail, the touch foil is likely mis-seated or the new foil has a controller whose gain is outside the panel's compensation range. Proceed to the OS reset in section 6 before declaring the foil defective.

6. Step-by-Step: OS Update with Reset to Factory Settings (ProSave)

If recalibration alone does not recover the panel, perform a clean OS update with the factory-reset option. This clears the stale touch-driver constants, the project file, and the runtime configuration, and reloads the image from scratch.

1. Open ProSave on the engineering station.
2. In the General tab, configure the connection:
   • Device type: TP1900 Comfort (V2 catalog entry)
   • Connection: Ethernet with the panel's IP, or USB with the panel's node
   • Save the configuration as a .p* file for repeat use
3. Switch to the OS Update tab. Browse to the correct V2 image (see section 4, step 7).
4. Tick Reset to factory settings. This is the option that clears the touch-calibration registry key.
5. Click Update OS. The transfer takes 5–10 minutes over Ethernet, longer over USB.
6. ProSave prompts to reboot the panel. Accept. The panel restarts twice: first to erase the previous image, then to load the new one.
7. After the second reboot, the panel arrives in the transfer/empty state. Do not load a project yet. First complete the touch calibration (section 5) against the freshly installed image.

7. Step-by-Step: OS Update via TIA Portal (Alternative to ProSave)

When ProSave cannot be used because the engineering station does not have the matching HSP, the OS update can be initiated from inside TIA Portal. The prerequisite is the matching project version and HSP.

1. Open the device's project in TIA Portal. The project version must be V14 SP1 or higher. V13 SP1 cannot flash a V2 panel.
2. Right-click the TP1900 Comfort V2 device in the project tree and select Online → HMI Device Maintenance → OS Update.
3. Select Reset to factory settings.
4. Click Update. The transfer proceeds via the channel configured under Online → Accessible nodes.
5. Wait for the panel to reboot twice.
6. Recalibrate touch (section 5) before downloading the project.

8. Image Version Compatibility

Comfort Panel V2 hardware requires a V14 SP1 or higher runtime image. The V1 hardware and the V2 hardware share the same family, but the bootloader and the touch-controller HAL differ. The compatibility matrix in the field is:

The image file name on disk encodes the catalog:

• V1: HmiTP1900_Comfort_V<version>.img
• V2: HmiTP1900_Comfort_V2_V<version>.img

The literal substring _V2_ must be present in the file name for the V2 panel. ProSave does not load a V1 image into a V2 panel even when the screen size and family match; the bootloader aborts with the device-type error.

9. Hardware Defect Indicators

After the OS reset and a clean recalibration, the panel will either respond correctly or exhibit one of the patterns below. Each pattern identifies a different failure mode.

10. Touch-Foil Replacement Checklist

After replacing the touch foil, run through this checklist before loading the project. Each item reduces the chance of the calibration routine aborting on the new surface.

1. Power down the panel and disconnect from mains.
2. Replace the touch foil following the manufacturer's service procedure. Torque the bezel screws to the value in the service manual (typically 0.4–0.6 Nm for the TP1900 family); over-torque bends the frame and distorts the resistive layer.
3. Inspect the ribbon cable. The contact pads must be clean and fully inserted. A half-inserted cable produces a vertical or horizontal dead band on the new foil.
4. Reconnect mains and power up. Open the Control Panel with a USB mouse (the touch is still uncalibrated).
5. Perform an OS update with Reset to factory settings via ProSave. This is the most reliable way to clear the old calibration constants.
6. Recalibrate touch with the 5×5 pattern under the 20-s time budget (section 5).
7. Verify the calibration by tapping each corner and the center of the screen. Each tap should produce a button-press at the visual location of the tap, within ±2 mm.
8. Only then download the project from TIA Portal.

11. Verification

After completing the recovery, verify the following items in order. Each is a hard pass/fail check.

1. The control panel shows the OS image version matching the one transferred (e.g., V15.01.00.02_04.01 or the V15.1 / V16 image you selected).
2. The 5×5 calibration completes with no on-screen error and the dialog closes normally.
3. Drag a finger or stylus along the four edges of the active area. The pointer must follow the contact within 2 mm at every edge, including the corners.
4. Open the project's start screen and tap a known button in each quadrant. All four taps register on the correct buttons.
5. Cycle power twice (cold restarts). The calibration must survive the restart. If it does not, the registry key was not committed; repeat section 6 with "Reset to factory settings".
6. From TIA Portal, perform an Online → Compile and Download of the project. The transfer must complete without a device-type warning.

12. Field Notes and Common Pitfalls

• Don't skip the time budget. The single most common reason for a failed calibration on a freshly installed foil is hesitating at the final crosshair. Time the sequence with a stopwatch during the first attempt.
• Don't trust the catalog name alone. Two TIA Portal installations on the same machine can have different HSP sets. Verify the file name on disk contains _V2_ before pointing ProSave at it.
• Don't reload an old project first. If the old project was compiled against a V13 image, loading it after a V15 OS update can leave the touch driver in a hybrid state. Reset to factory settings, then load the project.
• Don't use V13 on V2 hardware. The V2 bootloader cannot execute a V13 image. The panel will appear non-responsive, and ProSave will report a device-type mismatch if you try to re-flash from a V13 catalog.
• Don't assume the foil is fine because the new bezel screws are tight. An over-torqued bezel distorts the resistive layer and produces a non-linear response that the calibration routine cannot correct.