Proprietary HMI CompactFlash card replacement: the safe swap

Why the manual bans the old card

Proprietary means the card was sold as part of the old panel family: its format and contents are matched to that family, and it is not standard CompactFlash media. The new panel's manual expects standard CompactFlash and names the card type, the maximum capacity and the file system it supports. That line in the manual is the governing compatibility instruction.

A boot that works tells you the project survived the panel change. It exercises one read path once; treat the working card as temporary and schedule the swap.

Standard CompactFlash media splits at the file system: FAT16 for the smaller sizes and FAT32 for anything above the FAT16 ceiling. Some format tables hedge one boundary figure; the worked example below shows where it comes from and what it does to your card choice.

What you need

• The new panel's manual, memory-card section: card type, maximum capacity, file system, and the maker's own change procedure.
• A standard CompactFlash card inside those limits.
• A PC with the vendor's project software and the transfer path the manual names, cable or network.
• A card reader, if the tool prepares the card on the bench.
• The current project, read back from the panel and saved on the PC. Reading the project back from the panel is its own procedure and worth following before you change media.
• The panel's firmware revision, checked against the software version before any transfer.

Back up the project before you touch the card

Read the project back off the running panel, save it on the PC, and open the backup in the project software to confirm it loads clean. Copy any card-only files, logs, recipes, alarm texts, to the PC as well, straight off the card through the reader. The old card is the source of those copies, not the backup: it stays in the panel, unchanged, until the swap is done and checked. If the backup will not open or the panel will not read back, stop there; the swap waits until you hold a verified copy.

Swapping the card, in order

Do this at a planned stop: if the card change goes wrong, the panel stays down until it is put right, so it should cost a break, not production.

1. Note the panel model and its firmware revision, and check the revision against the project software's transfer requirements before moving anything; checking the firmware revision before a transfer explains the match.
2. Back up and verify the project as in the section above.
3. Prepare the new standard card with the vendor's own tool. The tool does more than format: in the documented card-preparation workflow the manual describes, the card sits in a reader, the project software opens it, and a shortcut-menu command creates the panel's system image on it. A file copy from the desktop does not perform that step, so an unprepared card behaves like a blank one at boot.
4. Change the card by the manual's procedure. Makers differ; some manuals move a safety catch into position for card service and eject the card with a brief press. Use the new panel's steps, not habits carried over from the old panel.
5. Load the project by the manual's download path, onto the prepared card or into the panel.
6. Boot the panel and read the startup messages.
7. Leave the old card labeled and unchanged until the checks below pass.

Example: a boundary-size card on a panel that lists FAT16

Inputs, and where each comes from: the card on the shopping list is standard CompactFlash at 2 GB, a size that sits exactly on the boundary the example computes; the panel manual lists FAT16 only; FAT16 numbers its clusters with 16 bits, which gives 65,536 addressable cluster slots (standard FAT geometry, a few of them reserved); standard cluster size is 32 KB and the extended setting 64 KB, both counted at 512-byte sectors.

The rule in words: a FAT16 volume can be no larger than its addressable clusters times its cluster size.

The arithmetic:

• 65,536 × 32 KB = 2,097,152 KB = 2,048 MB
• 65,536 × 64 KB = 4,194,304 KB = 4,096 MB

Result: with standard 32 KB clusters, FAT16 tops out at 2 GB, the limit format tables print as the usual one. The doubled 4,096 MB figure is the 64 KB cluster case, a setting many panel readers refuse.

Decision: above the FAT16 ceiling the card must be FAT32. On a panel whose manual lists FAT16 only, buy cards at or under that ceiling. If the manual lists FAT32, a larger card formats FAT32 and sits inside the limits, and above the FAT16 ceiling there is no FAT16 option at all.

How to check it worked

• The panel boots straight into the project screens. An unprepared or blank card produces a no-user-program message instead; the no-user-program boot message points at card preparation, not at the project, so fix the card before touching the software.
• Touch a button or force a bit and watch the controller value change on screen, so you know the project talks to the machine and not just draws it.
• Exercise the card-dependent functions once: open a trend, write a recipe, trigger a log entry, and read each back.
• Let the panel run an hour on the new card and watch the startup messages and alarm list for card faults; an hour of normal access is the smallest soak worth doing before the cabinet closes.
• If a card error appears anyway, check the card's capacity and file system against the manual's limits before reaching for another card; the example above is the check that catches most mismatches.
• If the card goes to a customer site or a sister machine instead of a swap in place, the preparation is identical; the flash-card update procedure covers that case.

The decision

Recommendation: swap to a standard CompactFlash card at the next planned stop, not during production. Back up the project and verify the backup, prepare the card with the vendor's tool, size it to the manual's file-system limit (at or under the FAT16 ceiling on a FAT16-only panel, larger only where the manual lists FAT32), change it by the manual's steps, and keep the old card labeled and unchanged until the new card has run a full shift of card accesses.

Once the machine's HMI is back on supported media, a separate screen by the line for shift notes or andon-style status is a different display class; that is what our shop-floor signage covers.

Questions