Yes, in most cases: the panel still runs a copy of the project, and the HMI software can read it back over its normal transfer connection. Read it out, save one untouched recovery master plus a working copy, verify 3 key screens against the running panel, and only then allow any download to the panel.
The fix is the documented read-back command: the HMI software can pull the running project off the panel over the transfer connection, usually in about 5 minutes for a 12-screen machine, and the whole recovery is four moves. Read the project out of the panel, save it as two files, check 3 screens against the running panel, and keep every download away until the check passes. This page is the emergency case, where the computer copy is already deleted but the line still needs its screens.
The routine habit of reading a project from a panel before editing it is covered in reading an HMI project from the panel before editing; the order of operations below is what matters once the deletion has already happened.
What you need
- The panel, still running the project and powered from its normal supply. A panel that has been cleared, or a replacement that was never loaded, has nothing to give back, and recovery then moves to archived copies and the panel maker's support.
- The maintenance PC with the HMI software installed. The release the project was written in is ideal; a newer release can usually convert an older read-back, and opening an old HMI project in new software covers that conversion.
- The connection the software documents for transfers: an Ethernet path to the machine network or a direct cable at the panel. If the PC cannot reach the panel, fix that first; why a panel project download fails through the network switch lists the causes in the order to check them.
- A folder on the PC for recovered files, and a second location off that PC for the master copy.
Read the project back from the panel
- Confirm the panel in front of you is the one whose project was lost. Match the machine number on the enclosure door to your list before anything else happens.
- Open the HMI software and choose
File > Start Project..., the entry the software documents for starting work with a panel. - Click
Read from Panel. The transfer runs from the panel to the PC. Every command that sends a project the other way stays out of this session, because a download replaces the copy the panel runs, and that copy is the thing being recovered. - Let the transfer finish. Leave the screen alone and do not cycle power to the panel while the software is working.
- Save the project to disk the moment the software offers, under a name that carries the machine number and the date, for example
mixer1-hmi-master-2025-06-11.
File > Start Project... and Read from Panel are the commands one common software family documents for this job. Other families put the same recovery behind a documented backup command: one major panel family documents the Backup command under the Online > HMI Device maintenance menu, where you select the interface type and the target device and click Create. Your own manual names the equivalent in its maintenance or transfer chapter, and that documented command is the only route to use.
Save one recovery master you never edit
Keep two files. The recovery master is the read-back exactly as it came off the panel: never opened for edits, stored off the editing PC on the file server or on a stick kept with the machine's documentation. The working copy is the file you open, convert, edit and eventually download from. When an edit goes wrong next month, the master is the rollback point.
Open the master once from its saved location to confirm the file on disk opens. A backup that refuses to open is common enough to have its own article: a project backup that stays locked until the read-only flag is cleared covers the case where the flag rides along with the file.
Check three screens against the running panel
A project that opens is the start of the check, and the check is what earns a download. Pick the 3 screens the operator touches every cycle: the main screen, the alarm or event list, and the busiest write screen, usually recipe or setpoint entry. In the recovered project, open each one and compare three things: navigation keys land where the panel's hardware expects, values carry the right units and scaling, and write buttons point at the addresses the machine actually uses.
Where the software includes a simulator, use it. A simulator runs the project on the PC for testing before any transfer to a panel, which makes it the safest place to click through navigation with no panel connected. Then repeat the comparison against the running panel itself, screen by screen, for the same 3.
Three screens is the figure for a typical machine because those three carry every operator write and every alarm the shift acts on. The figure moves with the machine: a line that writes recipes from 5 screens needs 5 screens in the check, and a download that carries a full re-commission deserves the whole project compared.
When a download is justified, check the panel's firmware revision first; checking the HMI firmware revision before a project transfer explains what to compare before the software will accept a clean transfer.
The recovery is finished when all four hold: the correct panel was read, the read-back opened and saved, the master reopens from its stored location, and the 3 screens match the running panel.
Example: the controls folder was emptied on Tuesday
A cleanup script on the maintenance PC deletes the HMI project folder on a Tuesday morning. The filler on line 2 still runs its 12-screen project, so the recovery runs the same shift:
Read from Panelover the machine network: about 5 minutes for the transfer.- Two files saved:
filler2-hmi-master-2025-06-11, untouched, plus a working copy. - The 3-screen check: main, alarm history and recipe select, compared against the running panel. 3 of 12 screens is 3 ÷ 12 = 25% of the project by screen count, and 100% of what the operator needs to run tonight's changeover.
- The window: 5 minutes for the read-back, 20 minutes to click through the 3 screens, 5 minutes to save and file both copies. 5 + 20 + 5 = 30 minutes, done before the next changeover.
No download happens at all that week. The panel keeps running its own copy, the master goes to the file server, and the next deletion becomes a copy job instead of a recovery. If the recipe screen had come back pointing at different register addresses, the rule flips: the download stays blocked until someone explains the difference, because a project with wrong addresses writes operator setpoints into the wrong registers.
When to stop and escalate
Stop and hand the job to the panel maker's support line once the PC reaches the panel reliably and any of these still holds:
- The software cannot read the panel at all.
- The read-back will not open or will not save from a clean retry.
- The read-back differs from the running panel in a way that touches machine operation.
Keep the recovered file untouched while the case is open, and keep downloads away from the panel while a difference is unexplained. The same order of operations, read the machine's memory before writing anything to it, carries well past HMI panels: recovering deleted programs from a machine control's memory walks the same sequence on a CNC.
Close the backup gap after the line is running
Back up on the event that matters, which is an approved project change, and store the new master off the editing PC the same day. Put the machine number and the panel location in every filename so a recovery never starts with a guess. Cut the deletion risk: a project folder only the controls group can write to, with change logging switched on, removes most single-keyboard accidents, and configuring change logging and locks against operator edits shows the settings involved. The master-copy discipline that goes with upload protection is covered in keeping a master copy behind upload protection.
Recommendation: Read the project back the day you find the files gone, save one dated recovery master off the editing PC plus one working copy, hold every download until the 3-screen check passes, and back up again the same day any later project change is approved.
If the review after the incident also asks for a board at the line showing the maintenance schedule and the date of the last backup, that is a separate screen from the HMI. We sell shop-floor signage displays for that job: they play offline from a card or run your own Android app, and the range sits in shop-floor screens and andon boards.
Questions
Another line runs what looks like the same project. Can I copy that file across?
Only as a reference, never as the recovery. Two panels that look identical can carry different scaling, addresses and screens if either machine was serviced separately. Use the twin's project to sanity-check the recovered one, and let the read-back from the panel that runs the machine be that machine's master. If the panel has nothing to read, a twin's project becomes a draft that needs a full screen-by-screen review before any download.
The panel was replaced last month. Does the read-back still help?
Yes, if the replacement was loaded with this machine's project at commissioning, because the read-back returns whatever that panel runs. If it was loaded from a near-miss version, the 3-screen check is what catches the difference. If the replacement has never been loaded, there is nothing to read, and recovery falls back to archived copies and the panel maker's support.
How long do we keep the recovery master?
For the life of the machine. Put the machine number and the recovery date in the filename, keep it off the editing PC, and when a new master is written after an approved change, move the old one to an archive folder instead of deleting it. An archived master is what makes a rollback possible months later, after a change made in good faith turns out wrong.
Planning information, not legal or engineering advice. Rules differ by place: check codes and permits with your local authority and your licensed trades.