Adding Separate Files to Siemens PCU20 Internal Flash

The Siemens SINUMERIK HMI Embedded PCU 20 is a compact Panel Control Unit used on machine tools equipped with Sinumerik 840D sl and 810D sl CNCs. The internal flash holds the HMI Embedded runtime, the compiled COM files, alarm text databases, language files, and bitmap graphics that drive the operator interface. During commissioning, retrofit, or field service, you frequently need to add or replace a single file - a new alarm text, an updated COM file, an additional language, or a custom screen mask - without rebuilding the entire image. The PCU 20 ramp-up menu exposes this capability through the "+" key. This article documents the procedure end-to-end, including the supported file types, the Compact Flash card layout, the boot-menu key map, and the verification steps that confirm a successful injection.

The "+" procedure is documented in the official Siemens upgrade instructions for HMI Embedded PCU 20 V06.05.49 and V06.05.80.01. Both manuals describe the function as "Add/replace separate files to internal flash" and confirm that pressing the "-" key copies the data directly from the PC card into the internal flash.

1. Overview of the PCU 20 Ramp-Up File-Add Procedure

The PCU 20 internal flash stores the HMI Embedded runtime tree, including compiled COM files, alarm text databases, language files, custom screen masks, and bitmap graphics. Two distinct procedures are available for changing the contents of that internal flash:

The "+" procedure is the correct tool when you have one or a few new files to inject, when the operator does not need a full image rebuild, and when downtime must be minimized. The full image procedure is the right tool when the change set is large, the internal flash is suspect, or the HMI Embedded version itself is changing.

2. Prerequisites

Confirm the following before starting the file-add procedure.

2.1 Hardware

• One PCU 20 panel control unit, powered down (mains off, not standby).
• One Compact Flash (CF) card, type I, capacity within the range supported by the installed HMI Embedded release (1 GB for V06.05.49, 2 GB for V06.05.80.01).
• A CF card reader/writer attached to the engineering station.
• Physical access to the front-panel softkeys of the PCU 20 during the ramp-up window.

2.2 Software and files

• The new file(s) to be added, in the format expected by HMI Embedded (see Section 4).
• A CF card formatted with FAT16. The PCU 20 ramp-up loader does not recognize FAT32, NTFS, or exFAT volumes.
• Optional: a known-good backup of the current internal flash, captured as a full PCU_20.ABB image, stored on the engineering PC.

2.3 Authorization and state

• Service-level access to the PCU 20 (the ramp-up menu is reached during the controlled boot phase, which requires the operator to be present at the panel).
• For paired NCU/PCU configurations, the PCU 20 boots independently of the NCK ramp-up state. The NCK does not need to be in a specific state for the PCU 20 file-add to proceed.

3. The PCU 20 Ramp-Up Menu: Key Map and Timing

The PCU 20 ramp-up menu appears on the HMI display during the boot sequence, after the POST and before the standard operator interface loads. The menu exposes the following softkey functions:

The menu window has a finite timeout (approximately 5 seconds in V06.05.49 and V06.05.80.01). If no key is pressed within the window, the PCU 20 continues ramp-up from internal flash. To re-enter the menu, cycle power and try again.

The "+" key is the only menu option that performs a granular, file-by-file injection. The "-" key performs a bulk replacement, which is destructive if the CF card contains a different directory set than what is already on the internal flash. Use "+" for partial updates; use "-" only when you intend to replace an entire directory tree (for example, the entire cus directory).

4. File Types Supported for Internal Flash Injection

The PCU 20 internal flash holds the HMI Embedded runtime tree, which mirrors the directory layout of the install source. The following file categories can be added or replaced via the "+" key:

The file extensions and paths above reflect the conventions documented for HMI Embedded. The exact internal path varies with the HMI Embedded version and with the installed options (Shopmill, Shopturn, HMI Advanced components).

5. Compact Flash Card Preparation: Format, Layout, and Naming Rules

The CF card must replicate the target internal-flash path for each file. The ramp-up loader matches the path on the CF card to the path on the internal flash and overwrites or creates the file accordingly.

5.1 Format the card

1. Insert the CF card into the PC card reader.
2. Format the card as FAT16.
   • Windows: format X: /FS:FAT
   • Linux: mkfs.vfat -F 16 /dev/sdX1
3. Verify the format with fsutil fsinfo volumeinfo X: (Windows) or blkid /dev/sdX1 (Linux).

5.2 Create the directory tree

Create the target directory tree on the CF card, matching the internal-flash path exactly. Examples:

• New alarm text file: X:\system\alarms\
• New language file: X:\system\lng\
• New custom screen: X:\system\cus\
• New icon: X:\system\ico\

5.3 Copy the file

Copy the new file into that directory using the exact name the HMI Embedded runtime expects (case-sensitive on the internal flash). Examples:

• X:\system\alarms\my_alarms.txt
• X:\system\lng\mylang.lng
• X:\system\cus\my_mask.com

5.4 Eject the card

Eject the CF card safely from the operating system before removing it from the reader.

6. Step-by-Step Procedure: Adding Separate Files to Internal Flash

1. Power down the PCU 20 (mains off, not standby).
2. Insert the prepared CF card into the PCU 20's CF slot. The slot is located behind a small cover on the front of the unit.
3. Power on the PCU 20.
4. Watch the HMI display. When the ramp-up menu appears, press the "+" softkey before the menu window times out.
5. The PCU 20 enumerates the files on the CF card, compares them to the internal flash tree, and lists the files that will be added or replaced.
6. Confirm the addition. The PCU 20 copies each listed file from the CF card into the corresponding location on the internal flash. Progress is shown on the display.
7. When the copy completes, the PCU 20 prompts for the CF card to be removed. Remove the card.
8. The PCU 20 continues ramp-up from the now-updated internal flash.

7. Generating and Applying the Full PCU_20.ABB Image

The full image procedure is the alternative to the "+" key and is appropriate when the change set is large or when the internal flash is suspected of being corrupt. The compiled image is a single file named PCU_20.ABB and is generated on the engineering PC using the HMI Embedded install tools (or the Shopmill/Shopturn install tools, depending on the option set installed on the panel).

1. On the engineering PC, install the matching version of the HMI Embedded (and Shopmill/Shopturn, if applicable) install package.
2. Use the install tool to compile the runtime tree into PCU_20.ABB.
3. Copy PCU_20.ABB to a FAT16-formatted CF card, placed at the card root.
4. Insert the CF card into the PCU 20, power on, and select the appropriate ramp-up menu option to write the image.
5. Verify the HMI Embedded version after ramp-up.

The PCU_20.ABB file replaces the entire internal-flash tree, including files that are not part of the change set. Use it for upgrades, recoveries, and option-set changes; use the "+" key for targeted file adds.

8. Directory Layout Reference for HMI Embedded PCU 20

The internal flash tree of a typical HMI Embedded install is organized as follows. The exact contents depend on the installed options.

• system/ - core runtime files
• system/cus/ - user customizations, including compiled COM files
• system/shopmill/ - Shopmill-specific COM files (when Shopmill is licensed)
• system/shopturn/ - Shopturn-specific COM files (when Shopturn is licensed)
• system/alarms/ - alarm text databases
• system/lng/ - language files
• system/ico/ - bitmap graphics used by the HMI
• system/help/ - help text files
• add_on/ - OEM add-on content
• oem/ - OEM-specific extensions

When placing a file on the CF card, the relative path from the card root must match the relative path from the internal flash root. The "+" key procedure does not perform any path translation.

9. Verification: Confirming Files Are Loaded into Internal Flash

After the "+" key procedure completes and the HMI is running, verify that the new file is in place.

1. On the operator panel, navigate to the HMI diagnostics area (or to a softkey that exercises the changed file, such as HS7 for a custom COM file in the cus directory).
2. For alarm text: trigger the alarm (or simulate it from the NCK) and confirm the new text is displayed.
3. For language files: change the active language to the one just added and confirm the new strings appear.
4. For bitmap graphics: navigate to the screen that uses the BMP and confirm the new image is rendered.
5. For COM files: open the operator screen that calls the COM and confirm the new behavior.

A more authoritative check is to power the PCU 20 down, remove the CF card, power back on, and confirm the new file is still served from internal flash after a clean boot. If the file disappears after CF removal, the ramp-up menu option selected was "PC card" (continue from PC card) rather than "+" (inject into internal flash).

10. Firmware Version Differences (V06.05.49 vs V06.05.80.01)

The "+" key procedure is documented in multiple HMI Embedded releases. Two reference documents from Siemens Support are:

• Siemens Upgrade Instructions HMI Embedded PCU 20 V06.05.49
• Siemens Upgrade Instructions HMI Embedded PCU 20 V06.05.80.01

The behavior of the "+" key is consistent between the two releases: the menu option is labelled "Add/replace separate files to internal flash" and the copy direction is from the PC card into the internal flash. Differences that field engineers have observed across releases include:

Always cross-check the exact behavior against the upgrade manual that ships with the version installed on the panel. The PDFs linked above are the authoritative references for V06.05.49 and V06.05.80.01.

11. Troubleshooting Matrix

12. Field-Proven Tips, Safety, and Recovery

• Back up first. Capture a full PCU_20.ABB image of the existing internal flash and store it on the engineering PC before any "+" key procedure. This is the fastest path to recovery if the new file causes an issue.
• Match versions. Match the HMI Embedded version on the engineering PC to the version installed on the PCU 20. A file compiled against V06.05.80.01 may not be compatible with a panel running V06.05.49.
• Use the right install set. For Shopmill/Shopturn COM files, the PCU_20.ABB image is built using the Shopmill/Shopturn install tool, not the base HMI Embedded install tool. Use the matching install set.
• Keep the CF card dedicated. Files left on the card from other systems can cause ramp-up to fail or to load an unintended image. Use a dedicated card for PCU 20 work.
• Power-cycle, not standby. The "+" menu is reachable only on a cold boot from mains. Standby wake does not re-enter the ramp-up menu.
• Do not mix "+" and "-" in the same session. If you press "-" by mistake, the entire target directory is replaced. Recover from backup before continuing.
• Document the change. Record the file name, the internal-flash path, the source path on the CF card, the HMI Embedded version, the date, and the operator who authorized the change. This is required by most machine-builder change-control procedures.

13. Frequently Asked Questions