The screen is dark and the line is stopped.
An HMI failure rarely stops the process itself, but it stops the people running it. Most faults fall into a small number of categories, and knowing which one you have saves a great deal of time.
Is it the panel, the network, or the project?
Almost every HMI fault resolves to one of three things. The hardware has failed, the communication path to the controller is broken, or the project running on the panel has become corrupted or was never quite right.
Distinguishing between them is usually quick. A panel that boots and shows a comms error has working hardware and a network problem. A panel that shows a backlit but blank screen is usually a hardware or project loading fault. A panel that works until a specific screen is opened has a project problem.
The complication is what happens next. Replacing an HMI is straightforward only if you have the project file. A large proportion of the calls we get are not really about the fault at all, they are about the fact that nobody has a backup.
Faults we work on.
Grouped by what the panel is actually doing.
Blank or frozen screens
Backlight failures, boot loops, corrupted firmware and panels that power up but never load the runtime.
Communication loss
The panel is fine but cannot reach the controller. Addressing, cabling, switch configuration or a driver mismatch after an upgrade.
Touchscreen problems
Dead zones, drift and calibration loss. Often a resistive panel reaching the end of its life in a high use application.
Corrupted projects
Screens that error, tags that no longer resolve or a runtime that fails after a partial download.
No backup available
Recovering the project from the panel where possible, or rebuilding it from the PLC tag database where it is not.
Locked or untranslated panels
Imported equipment with Chinese language projects or password protection, where replacement is frequently the practical answer.
Before you call, check these.
Five minutes of checks that resolve a meaningful share of HMI calls.
- Power. Confirm 24V at the panel terminals, not just that the supply is on. Shared supplies sag when something else starts.
- Ethernet link lights. No link is a cable or switch problem, not an HMI problem.
- IP address conflict. Particularly after any device has been replaced. Two devices on one address produce baffling intermittent behaviour.
- Recent changes. Firmware updates, PLC program downloads and network changes are the most common triggers.
- Does the PLC still run? If the process is fine, the fault is between panel and controller, not in the control logic.
- Try a cold power cycle. Fully off for thirty seconds, not a warm restart. It resolves a surprising number of runtime faults.
- Check the SD card or USB. Some panels store the runtime externally, and a failing card presents as a boot fault.
- Find out whether a backup exists. This determines everything about how the rest of the job goes, so it is worth knowing before you call.
Answers before you call.
Allen-Bradley PanelView and PanelView Plus, Siemens Comfort and Basic Panels, Ignition clients, Wago and CODESYS visualisation, Opto 22 groov, plus a wide range of imported panels including Weinview, Kinco, Samkoon and Delta.
Where the panel still boots, the project can often be uploaded from it. Where it does not, the options are recovering from any old engineering laptop that ever connected to it, or rebuilding the screens against the PLC tag database. The second is real work but it is entirely feasible.
Frequently yes, if the project file can be opened. Where the software is unavailable or the project is locked, replacing the panel with a supportable one is usually cheaper than continuing to fight the original.
Yes. This is common work and it is an opportunity as well as a repair, since the replacement can use current screen design rather than reproducing a layout from 2008. Mounting and cutout differences are usually solvable with an adapter plate.
Not always. Photographs of the screen, the fault message and the panel rear will often identify the category of fault. Where remote access to the network exists, we can look at the panel and the controller directly.
Send a photo of the screen.
Whatever it is showing, an error, a blank backlight or nothing at all, usually tells us which of the three categories you are in.
Or call (801) 946-2710, Monday, Friday, 8:00am, 4:30pm MT