HMI web pages fail but remote control works: factory reset path

What the symptom pair points to

• Web pages fail, remote control still connects. Panel state or web configuration. This is the case the reset below fixes. The same two-path split shows up with other second connections; the FTP variant is worked through in HMI panel web server stops responding but FTP still works.
• Both paths dead. Power, network or the panel itself. If you are testing from off site, the port forwarding path fails on its own often enough to have its own checklist: HMI remote access port forwarding fails: test each step. Nothing below applies until a client connects from inside the plant.
• Pages fail from one browser or one PC only. The client. Clear the cache, check the proxy settings, try a different browser before you touch the panel.
• Pages have never loaded since setup. Configuration, not failure. Newer panels ship with the secure HTTPS web server disabled by default, and it has to be switched on in the programming software before any https:// address will answer.

Checks before you touch the panel

1. Fix the address and scheme first. A browser asking for https:// knocks on TCP port 443, plain http:// on TCP port 80, the standard ports. A panel serving plain pages answers on port 80 and refuses port 443 every time, so try the other scheme before anything else.
2. Retry from a second browser on a second PC. If the pages load there, stop: the fault is the first client, and the panel needs nothing.
3. Write down the exact browser message. A timeout or a cannot-connect message means nothing answered on that port; a page-not-found result means the browser reached something and got nothing useful back.
4. Confirm the remote control client still connects, and note it with a time and date. That single fact is what sends the job down the reset path instead of the network path.
5. Ask what changed. A project download, a settings change or a power event on the day the pages died is the best clue you will get. If the pages died right after a program download, that case has its own path: Web server unreachable after an HMI program download.

Back up the project first

The restore you are heading for erases the panel. Save the project with the programming software, copy the file off the panel, and open it to confirm it is this machine's project. Give the save-and-open check 5 minutes; it is the cheapest insurance in the whole job. The safe way to take and check a backup, including what to verify before you trust one, is in Back up and restore an HMI panel project the safe way. No verified backup, no reset: the wipe trades a page problem for a lost project.

Run the restore to factory defaults

On the panels that document this reset, the route runs through the setup screens on the touch screen itself: hold the upper-left corner of the screen for 10 seconds, press Memory, then select Restore to Factory defaults. The restore erases the project file and returns touch calibration to its factory defaults. Let it run to the end, which takes a few minutes on a typical panel; do not power the panel down part way.

If your panel's setup screens word these choices differently, stop and follow its hardware manual's System Setup chapter. The destructive choice has to be the documented one.

If the pages still fail after the reset, the documented next step is a firmware update followed by a second restore to defaults. Do the update from a USB stick the way Update HMI panel firmware from a USB stick restore sets out, run the defaults reset again, and retest.

Reload the project and test both paths

Load the project back from the verified backup and recalibrate touch if taps land off their targets. If your panel serves pages uploaded separately from the project, upload them again; Factory reset deletes HMI panel web files: recover them covers getting web files back after a reset.

Then retest both paths from the same browser that failed: the pages at the panel's http:// address on TCP port 80, and the remote control client. Both have to pass. Pages back with the remote client dead is not a repair.

Worked example: pages dead at one address, remote control alive

A packaging line panel sits at 192.168.1.50. The remote control client connects and shows the line screens. The browser reports it cannot reach https://192.168.1.50.

1. Scheme check. https:// targets TCP port 443 and the panel serves plain pages on TCP port 80, so try http://192.168.1.50. Still nothing, and the same from a second browser on a second PC. The client is clear. Elapsed: 2 minutes.
2. Path check. The remote control client still connects, so power, network and panel are up, and the web-serving side is the suspect.
3. Backup. The project is saved off the panel with the programming software and opened to confirm it is this machine's project. Elapsed: 5 minutes.
4. Reset. Upper-left corner held for 10 seconds, press Memory, select Restore to Factory defaults. The panel erases the project and resets touch calibration. Elapsed: 5 minutes.
5. Reload and retest. Project back from the backup, touch recalibrated, and http://192.168.1.50 now serves the pages on TCP port 80; the remote client still connects. Elapsed: 3 minutes.

Result: pages back on port 80, both paths passing, about 15 minutes of work from first check to retest, no hardware replaced. Had step 5 still failed on port 80, the next documented step is the firmware update and a second defaults reset.

If the pages fail again

A successful reset is a recovery result; the cause stays open. If the pages die again, make one maintenance note before the next reset: panel model, the firmware version the panel reports, the project version, the browser message, the address used, and whether the remote control client connected at the time. Keep the verified backup with the machine's maintenance file so a repeat reset never leaves the line without its project, and give support the note with the backup. A second wipe without the note is guesswork.

Recommendation

Recommendation: when the remote control client still connects and only the web pages fail, give the address and client checks 10 minutes first: try the http:// address on TCP port 80, then a second browser on a second PC. If the pages still fail, back up the project and verify the backup, run the setup-screen restore to factory defaults (upper-left corner held 10 seconds, press Memory, select Restore to Factory defaults), reload the project, and retest both paths. Go to firmware only after a reset has failed, and keep the verified backup with the machine's maintenance file either way.

Questions