Adding PLC Alarm Text on SINUMERIK 840Dsl HMI: TS-QM Conversion Fix

This procedure documents how to surface a user-defined PLC alarm text (for example A620070) on a SINUMERIK 840Dsl HMI when the standard Setup menu, the Commissioning Manual workflow, and the Access MyMachine / P2P route all leave the alarm visible only by number. The hardware configuration referenced is OP015A operator panel + TCU30.3 thin client unit + PCU50.5 industrial PC running SINUMERIK Operate. The root cause is a Qt translation chain failure between the editable .ts source file and the compiled .qm binary that the HMI runtime actually loads. The complete fix is to validate the .ts XML, then delete the corresponding .qm so the translation service regenerates the binary on the next HMI boot.

Problem Statement

On a SINUMERIK 840Dsl grinding machine with the configuration OP015A + TCU30.3 + PCU50.5, a PLC input trigger raises alarm number A620070 in the HMI alarm line but the descriptive text never appears. The integrator attempted three documented approaches from the SINUMERIK 840Dsl Commissioning Manual and the Operate help system:

1. Editing the alarm text from Setup > HMI > alarmtext. Only the entry Userdef_Ka_nc contains the manufacturer-supplied NC alarm text. The other three entries (oem_alarms_plc, oem_alarms_cycles, oem_partprogram_messages) are empty placeholders. Adding a row in oem_alarms_plc and rebooting did not change the runtime display.
2. Manually editing the Qt Linguist source files kapp_alarms_chs.ts and kapp_alarms_eng.ts directly in C:\ProgramData\Siemens\MotionControl\user\sinumerik\hmi\lng and rebooting. No text appeared.
3. Connecting through Access MyMachine / P2P. The remote project view only exposed the OEM file path. The user path remained inaccessible and the PLC DB2 interface was not used by the machine builder, so this route did not produce a deployable change.

SINUMERIK 840Dsl Alarm Number Format

The six-digit alarm number that appears on the HMI is structured. The first digit identifies the alarm source per the SINUMERIK 840Dsl alarm system:

An alarm number beginning with 6 originates from the user PLC program. The second digit encodes the clearance behaviour: 0 = clearable by Cancel, 1 = clearable only with NCK reset, 8 = self-clearing on condition fall. Digits 3 - 6 are the integrator-assigned alarm ID. The full number 620070 therefore parses as: user-PLC alarm, normal clearance, ID 20070. Siemens does not ship default text for user-defined PLC alarms; the text is the integrator's responsibility.

HMI Component Roles (OP015A + TCU30.3 + PCU50.5)

Locating the correct file path requires understanding the SINUMERIK 840Dsl HMI hardware layout:

When the PLC toggles the input that triggers A620070, the PLC writes the alarm number to the PLC/NCK interface. The NCK forwards the alarm to the HMI software running on the PCU. The HMI looks up the alarm number in the compiled .qm for the active language. If no text matches, the alarm row shows only the number.

Why the Three Common Methods Fail

Method 1 - Setup > HMI > alarmtext

The Setup > HMI > alarmtext menu exposes the four built-in OEM alarm files (oem_alarms_plc, oem_alarms_cycles, oem_partprogram_messages, Userdef_Ka_nc). The fourth file is pre-populated with the machine builder's NC alarm text. The first three are intentionally empty. Adding a text in oem_alarms_plc from the menu writes to a parallel OEM path that the runtime does not consult for the active alarm list. The change is also not always persisted to the user .ts source, so the next reboot loses the entry.

Method 2 - Direct .ts File Edit

The .ts file is the Qt Linguist source format (XML). It is the editable source. SINUMERIK Operate does not load .ts files at runtime. The runtime loads only the compiled .qm binary. If a .qm with a newer timestamp than the .ts exists in the same directory, the conversion service skips the .ts entirely. The diagnostic test is simple: compare file timestamps. If the .qm modified time does not change after a reboot following a .ts edit, the runtime did not recompile.

Method 3 - Access MyMachine / P2P

Access MyMachine allows remote access to the PCU file system. The P2P project view shows only the OEM file path. The user scope (user\sinumerik\hmi\lng) is hidden. Edits made through P2P land in the OEM scope, not in the user scope that the active HMI session reads. This route therefore cannot add a user PLC alarm text to the live alarm system without an additional copy step.

The .ts to .qm Conversion Process

SINUMERIK Operate uses the Qt translation framework. The conversion chain is:

1. The .ts source (XML, editable) is stored in the user lng directory.
2. On HMI boot, the translation service checks each .ts against its companion .qm.
3. If a .ts is newer than its .qm, the .qm is recompiled from the .ts.
4. If a .qm is missing entirely, a new .qm is generated from the .ts.
5. If the .qm timestamp is more recent than the .ts, the existing .qm is used unchanged.
6. The runtime loads the .qm into memory; subsequent edits to the .ts have no effect until the next recompile.

The critical detail: SINUMERIK will not overwrite a .qm that already exists with a newer timestamp than its source .ts. This is the behaviour observed in the original problem report - the .ts file was edited, the .qm should have been older, but the .qm was not regenerated because of a second issue: a literal CR/LF inside the <translation> tag made the .ts XML invalid, so the parser rejected the file before conversion could begin.

Root Cause: Stale .qm Binary Files

The original post identified two distinct failure modes that are easy to confuse:

The fix for both is identical: delete the .qm file. The next HMI boot will detect the missing .qm, parse the .ts from scratch, and generate a fresh .qm. The conversion runs during HMI initialisation; on the next alarm event, the descriptive text appears.

Step-by-Step Procedure

Prerequisites

• Service-level access to the SINUMERIK 840Dsl HMI (keyswitch position 3, or service login: service / SINUMERIK, or the machine-specific service password).
• Network access to the PCU50.5 (RDP, VNC, or local keyboard/mouse) OR direct access to the PCU file system.
• Knowledge of the six-digit alarm number to add (for example 620070).
• Backup of the active CFG image before any file edit.
• Text editor that preserves encoding and line endings correctly: Notepad++, VS Code, UltraEdit. Do not use Windows Notepad, which can introduce CRLF and BOM issues.

Procedure

1. Switch to Service mode. Turn the keyswitch to position 3, or log in as the service user.
2. Open the HMI file system. On the PCU, navigate to: C:\ProgramData\Siemens\MotionControl\user\sinumerik\hmi\lng
3. Identify the active language file. Standard names:
   • kapp_alarms_eng.ts / kapp_alarms_eng.qm (English)
   • kapp_alarms_deu.ts / kapp_alarms_deu.qm (German)
   • kapp_alarms_chs.ts / kapp_alarms_chs.qm (Simplified Chinese)
4. Back up the original. Copy the .ts to kapp_alarms_eng.ts.bak (and the .qm to kapp_alarms_eng.qm.bak).
5. Open the .ts file in the proper text editor. Verify the first line is: <?xml version="1.0" encoding="utf-8"?>
6. Search for the alarm number. Use Find for the six-digit string (e.g. 620070) or the full token A620070. The <source> tag in Qt Linguist uses the digits only, without the A prefix.
7. If the entry exists, edit the <translation> tag. If it does not exist, add a new <message> block inside the appropriate <context>:

   <context>
       <name>Alarms</name>
       <message>
           <location filename="kapp_alarms_eng.ts" line="123"/>
           <source>620070</source>
           <translation>Spindle overload detected - check lubrication</translation>
       </message>
   </context>

8. Critical rule: the entire <translation> tag, from opening to closing, must be on a single physical line. Do not press the keyboard Enter key inside the tag. For a forced line break in the displayed text, use the XML entity 
 which Qt renders as a line break at display time.
9. Save the .ts file. Confirm the file size increased by the new text length. Confirm no Enter was inserted inside any <translation> block.
10. Delete the corresponding .qm file. For English: delete C:\ProgramData\Siemens\MotionControl\user\sinumerik\hmi\lng\kapp_alarms_eng.qm. Repeat for every language file you have edited.
11. Trigger an HMI restart. From the HMI main menu: Diagnostics > HMI restart. Alternatively, perform an NCK reset followed by a full PCU reboot. The translation service regenerates the .qm files during the boot sequence.
12. After the HMI returns to operation, verify the .qm file exists again in the lng directory and has a Modified timestamp equal to the most recent HMI boot time. The file size should be roughly proportional to the source .ts size (compaction ratio is typically 30% - 50%).
13. Trigger the alarm by toggling the PLC input that generates A620070. The HMI alarm list should now display the number, the new text, and the timestamp.

Editing the .ts File: XML Syntax Reference

A valid Qt Linguist .ts entry has the structure shown in the procedure above. The following rules must be observed:

Common .ts errors that prevent .qm regeneration:

• Unclosed <message> or <context> tag.
• Literal CR/LF inside the <translation> tag (the most common cause of silent rejection).
• Mismatched or unescaped double quotes inside the text.
• Wrong encoding declaration (the encoding attribute must match the file's actual encoding).
• BOM added by the editor (Qt's parser does not accept BOM in front of the XML declaration).
• Empty <translation> tag - Qt may skip the entry if the translation is blank.

Verification Procedure

1. Timestamp check. Open Windows Explorer, right-click the .qm file, select Properties. The Modified date must equal the time of the most recent HMI boot. If the timestamp is unchanged, the .ts was rejected by the parser.
2. Alarm list check. On the HMI, navigate to Diagnostics > Alarm list. Trigger the alarm (toggle the PLC input). The alarm row should show the number, the descriptive text, and the timestamp.
3. Language check. Change the HMI language via Start-up > HMI > Language (if available) and trigger the alarm again. The translated text from the corresponding language .ts file should display.
4. Persistence check. Perform an NCK reset (without powering down the PCU) and verify the alarm text remains loaded.
5. Full reboot check. Power cycle the PCU and confirm the .qm is regenerated on the next boot and the alarm text persists.

Multi-Language Alarm Text

The .ts / .qm pair exists per language. Standard SINUMERIK Operate language files in the user lng directory:

To add multi-language text, edit the .ts file for each target language, save as UTF-8 (no BOM), and delete the corresponding .qm. The HMI boot regenerates one .qm per language. The first line of every .ts must be <?xml version="1.0" encoding="utf-8"?>. For non-Latin scripts (Chinese, Japanese, Korean), verify the editor saves the file in UTF-8 without a BOM; the BOM causes Qt's parser to reject the file.

File Path Reference

Edits must be made in the user scope. The OEM and add-on scopes are typically write-protected; even if a write succeeds, the runtime will not load the file from those scopes for the active alarm list.

Troubleshooting Matrix

Edge Cases and OEM Separation

SINUMERIK Operate separates user, OEM, and add-on file scopes. The runtime resolution order for an alarm number lookup is: add-on, OEM, then user. If a text is defined in the OEM scope, it overrides a user-scope definition. The integrator must therefore ensure that the OEM .ts does not contain an entry for the same alarm number, or the user entry will be ignored.

The PLC interface in SINUMERIK 840Dsl is DB2. The user PLC writes alarm numbers to DB2 in the format defined by the SINUMERIK 840Dsl PLC Programming Manual. The HMI then reads DB2 to populate the alarm list. If the machine builder is not using DB2 (as in the original report), the alarm numbers are still being driven by the PLC, but the HMI-side text lookup is independent of DB2 - the text is in the .ts / .qm files regardless.

For alarm numbers above the user-PLC range (above 6xxxxx), the HMI looks up the text in the Siemens-supplied alarm database. The user scope cannot override these. For numbers in the 6xxxxx range, the user scope is the only source for text.

Alternative: TIA Portal Openness Workflow

For users maintaining alarm text lists in TIA Portal (typically for S7-1500 / ET 200SP PLCs that feed the HMI), the TIA Portal Openness API provides programmatic management of PLC text lists. The Openness API supports copying PLC text lists to a library as a Master copy, or deleting PLC text lists from library Master copy folders. This enables automated text management for fleet deployments and is documented in the official TIA Portal Openness API reference. See the Managing alarm text list in PLC and Mastercopy library documentation for the v21 Openness API procedure.

Best Practices and Pitfalls

• Always back up the .ts and .qm files before any edit. A CFG image backup is the safest restore point.
• Use a proper text editor (Notepad++, VS Code, UltraEdit, Qt Linguist) - not Windows Notepad, which can introduce CRLF and BOM issues that break Qt's parser.
• Delete the .qm only AFTER you have validated the .ts syntactically (open in Qt Linguist; the parser will flag any XML error).
• Restart the HMI, not just the NCK. The .ts -to- .qm conversion runs on HMI boot, not on NCK reset.
• Edit only the user scope (user\sinumerik\hmi\lng). The OEM and add-on scopes are typically write-protected at runtime.
• For multi-language support, edit all target language .ts files before the next HMI boot. The conversion runs once per boot, generating one .qm per .ts.
• For fleet management, use TIA Portal Openness to maintain text lists centrally. Export the text list from TIA Portal, then deploy via Access MyMachine or a CFG image update.
• Avoid duplicating alarm numbers across user and OEM scopes. The OEM scope wins on conflict.
• Test the alarm trigger in service mode before handing the machine back to production. Verify text in all installed languages.
• Document the alarm number, the source .ts file, and the boot timestamp in the machine log so future service engineers can re-derive the configuration.