Fixing MTP1500 ParameterSet Transfer Failures in TIA Portal V21

Pre-configured parameter sets in TIA Portal V21 sometimes fail to populate with values, dataset names, or multilingual titles after transfer to a SIMATIC MTP1500 Unified Comfort Panel. The configuration compiles and loads cleanly, but the parameter view in runtime shows empty parameter data sets, blank dataset names, or missing localized titles. This reference documents the engineering-side causes, the runtime image compatibility constraint, and the field-proven corrective sequence for restoring parameter-set transfer on Unified Comfort Panels.

1. Problem Summary

When a parameter set is configured in TIA Portal V21 using a WinCC Unified screen and is bound to a PLC user-defined type (UDT) plus an internal SessionLocal UDT, the transfer to the MTP1500 panel may produce one or more of the following symptoms:

• Parameter set is created on the panel, but all element values are empty / zero even though default values are defined in the engineering.
• Dataset name is blank in the parameter view header on the HMI.
• Multilingual title of the dataset is visible in one language and missing in another even though the project only configures two languages (for example en-GB and fr-FR).
• The Parameter set pane under Runtime settings > Parameter sets lists the configured set, but the runtime shows no selectable dataset.
• After a Rebuild all of hardware and software, the symptom persists across multiple download cycles.

The behavior is reproducible with the following configuration baseline:

• TIA Portal V21 (Step 7 V21 + WinCC Unified V21)
• Panel device version: MTP1500, article number 6AV2 128-3xxx family, firmware V21
• Parameter screen backed by a Parameter set control with a UDT tag (PLC side) and an internal SessionLocal UDT tag (HMI side)
• Two active runtime languages (en-GB, fr-FR)
• Transfer option: Keep current parameter set-related data in runtime unchecked

2. Affected System Configuration

3. Root Cause Analysis

Three engineering-side conditions, alone or in combination, are responsible for the symptoms described. They are listed in the order in which they are most commonly encountered in field reports.

3.1 Uninitialized UDT Elements

The parameter set control stores one element per PLC UDT member. If a UDT member (especially a String, WString, Struct, or array) is declared without a default value, the WinCC Unified engineering does not write any payload for that element into the parameter set XML. The runtime then initializes the element with the type's zero value (empty string, 0, 00:00:00, etc.) and displays it as blank.

This is the dominant cause of "the parameter set has no value" symptoms.

3.2 Dataset Name Missing in One or More Languages

Each parameter set has a name property and a multilingual title. If the title is filled in only for the reference language (for example English) and left blank for the second language, the engineering sometimes transfers an empty multilingual record. The runtime then shows the dataset under the localized list with a blank entry, even though the underlying configuration exists.

3.3 Engineering / Runtime Image Version Mismatch

Unified Comfort Panels from TIA Portal V18, V19, or V20 cannot host parameter sets that are configured in TIA Portal V21. Conversely, a V21 panel that has been downgraded to a V20 image will reject the V21-format parameter set descriptor. The most common field failure is: the project is V21, the panel is loaded with a V21 image, but the panel image on the device does not match the engineering's expected image family. This typically shows up as a parameter set visible in the engineering but not selectable in the runtime, and is the symptom the Siemens engineering support team has flagged as a known V21 issue requiring a support ticket.

4. Pre-Transfer Diagnostics Checklist

Run through every item before re-transferring the project. Each check either confirms a root cause or removes one variable from the failure equation.

1. Verify the panel image version. Open Project tree > Devices & networks > [MTP1500] > Online & diagnostics > Information. Confirm Image version reports a V21 build. If it reports V20 or earlier, reflash using the V21 image before continuing.
2. Verify the TIA Portal build. Help > About > Installed software must show SIMATIC STEP 7 V21 and SIMATIC WinCC Unified V21. Mixed V20/V21 is not supported.
3. Audit the UDT. Open the PLC UDT and the HMI SessionLocal UDT. Every member must have a default value, including nested structs and string members.
4. Audit the parameter set configuration. Open the screen containing the Parameter set control. Verify the dataset name text field is non-empty for every configured language. The reference language dropdown must equal the project's first runtime language.
5. Audit the language list. Project tree > Languages & resources > Project languages and Runtime settings > Languages & fonts must contain the same locales as the panel's Languages & fonts settings. Remove any language that the panel does not have a font for.
6. Inspect parameter set XML. In the project working directory, locate the generated parameter set descriptor under \IM\HMI\ParameterSets\. Open it in a text editor. Empty <DefaultValue> nodes for string members indicate uninitialized UDT members.
7. Confirm the transfer option. In the Load preview dialog, expand the Software (PC / HMI) node and confirm Keep current parameter set-related data in runtime is cleared. The default state for a fresh project is unchecked, but an existing plant state may have stored the option.
8. Perform a full rebuild. Project tree > right-click > Compile > Rebuild all (Hardware and Software). This regenerates every descriptor, including the parameter set XML.

5. Step-by-Step Resolution Procedure

Follow the sequence below. Each step addresses one root cause and should be confirmed before proceeding.

5.1 Initialize Every UDT Member

1. Open the PLC UDT used by the parameter set.
2. For each member, populate the Default value column. Use the smallest valid value for the type:
   • Bool → FALSE
   • Int, DInt, Real, LReal → 0
   • String → explicit empty string '' (two single quotes, not a space)
   • WString → ''
   • Time, Date, Time_Of_Day → T#0s, D#1990-01-01, TOD#00:00:00
   • Struct members → initialize each leaf element recursively
3. Open the HMI SessionLocal UDT and repeat step 2. The two UDTs must remain structurally identical.
4. Compile the PLC block and the HMI tags to apply the new defaults.

5.2 Populate the Dataset Name in Every Language

1. Open the screen with the parameter set control.
2. Select the parameter set, then in the properties pane go to Properties > Texts > Name.
3. For every language listed in Runtime settings > Languages & fonts, type a non-empty name. There is no shortcut — even a single trailing space counts as a value, but a deliberately empty value is treated as a missing translation.
4. Repeat for the parameter set's ToolTip and any other multilingual property the project exposes.
5. Compile the screen.

5.3 Align the Panel Image to TIA Portal V21

1. Open Online & diagnostics > Information on the MTP1500 and read the current image version.
2. If the image is V20 or earlier, obtain the V21 image from the TIA Portal V21 downloads page or the SIMATIC Automation Tool.
3. Use Online & diagnostics > Operating mode > Update operating system to flash the V21 image. Allow 5-12 minutes for the MTP1500.
4. Once the image reports V21, restart the panel and reconnect from TIA Portal.

5.4 Rebuild and Re-Transfer

1. Right-click the HMI device and choose Compile > Rebuild all (Hardware and Software).
2. Open Online > Load to device > Software (all).
3. In the load preview, expand Software (PC / HMI) and verify:
   • Parameter sets is listed with the configured set.
   • Keep current parameter set-related data in runtime is unchecked.
4. Complete the download. Do not interrupt the transfer; the parameter set descriptor is written in a single atomic operation near the end of the load sequence.
5. After the load completes, perform a controlled power cycle of the panel (Runtime > Stop operating system, then power off / power on) so that WinCC Unified re-reads the parameter set descriptor from non-volatile storage.

6. Verification Procedure

After the corrected transfer, validate that the parameter set is fully present and editable in runtime.

1. Start runtime on the MTP1500.
2. Navigate to the screen that hosts the parameter set control.
3. Open the parameter set selector. The dataset name must display the localized text (not blank) in both en-GB and fr-FR.
4. Open the dataset. Every element defined in the UDT must display a non-empty value matching the default configured in step 5.1.
5. Edit one element, save the dataset, and switch the runtime language. The change must persist across the language switch and across a screen change.
6. From the engineering PC, reconnect to the panel and use Online & diagnostics > Parameter sets to read back the saved dataset. Compare the values to what is on screen.

7. Workarounds and Mitigation

If the engineering-side corrections do not restore the transfer, the following measures are documented as field-proven workarounds.

7.1 Open a Siemens Support Ticket

The Unified V21 parameter-set transfer path has been reported to Siemens engineering as a known issue. When the engineering configuration is correct (per Sections 5.1-5.3) and the symptom persists across multiple rebuilds, open a support request at Siemens Industrial Support Request. Attach the TIA Portal project archive (created via Project > Archive) and the panel's Service & Support dump. Siemens may provide a hotfix for the Unified runtime image.

7.2 Create the Parameter Set in Runtime

Until the engineering transfer is restored, the parameter set can be created manually in runtime. Operators with sufficient rights can use the parameter view to add a new dataset, populate elements from the live PLC UDT, and save. The set is persisted to the panel's internal storage and survives power cycles. This is a workaround only — the engineering-side fix remains the proper resolution.

7.3 Use Export / Import

WinCC Unified supports an Export parameter set and Import parameter set action in the parameter view. As an interim workflow:

1. Create the parameter set in the engineering in a test project where the UDT defaults are populated.
2. Export the descriptor to a .json file.
3. On the MTP1500 runtime, use Import parameter set to load the descriptor into the production project.

The export/import path bypasses the engineering-to-panel descriptor transfer code path, which is where the V21 issue manifests.

7.4 Pin the Engineering Build

Once the issue is resolved, freeze the TIA Portal V21 Update level across the engineering team. Mixing TIA Portal V21 with different cumulative updates on the same project has been observed to reintroduce parameter-set inconsistencies.

8. Cross-Platform and Related Notes

8.1 Other Unified Comfort Panels

The MTP1500 shares its firmware family with the MTP700, MTP1000, MTP1200, MTP1900, and MTP2200. The procedures documented in Sections 5 and 6 apply identically to all six form factors. The only differences are physical (display size, article number, power consumption). Article numbers in the MTP family follow the 6AV2 128-3... pattern.

8.2 Relation to Recipes

Parameter sets in Unified V21 are conceptually adjacent to, but distinct from, the recipe system used in WinCC Comfort/Professional. Recipes store structured production data with a fixed schema; parameter sets expose editable parameter snapshots bound to a UDT. A screen that uses both features must initialize the UDT defaults for the parameter set independently from the recipe structure.

8.3 SessionLocal UDT Pattern

The SessionLocal tag is an HMI-internal UDT used to hold the parameter view's current edit state without writing to the PLC. The pattern is:

1. PLC UDT — canonical structure on the controller.
2. HMI SessionLocal UDT — mirror structure, only on the panel.
3. Parameter set control — bound to the HMI SessionLocal UDT for the editing session and to the PLC UDT for the data record that is loaded / saved.

If the two UDTs drift in structure (added member on one side only), the parameter set descriptor generation may silently drop the unpaired member. Use the Compare > PLC / HMI type comparison tool to keep the two UDTs in lockstep.

9. Engineering Audit Checklist

Use this as a single-page reference when commissioning a new MTP1500 parameter set project on TIA Portal V21.

• TIA Portal V21 with matching WinCC Unified V21 installed.
• MTP1500 device version V21 in the project, panel image V21 on the device.
• PLC UDT and HMI SessionLocal UDT structurally identical, every member initialized.
• Dataset name populated in every runtime language.
• Project languages list and panel Languages & fonts list identical.
• Rebuild all (Hardware and Software) performed after every change.
• Load preview shows the parameter set under Software (PC / HMI).
• Keep current parameter set-related data in runtime unchecked during the verification transfer.
• Panel power-cycled after the transfer.
• Verification per Section 6 passed for both en-GB and fr-FR.

10. Frequently Asked Questions