The setup screens sit behind a press-and-hold on a small square in the upper-left corner, so quick taps never open them. Hold the corner for 3 seconds or slide in from just off the glass, recalibrate with the contact operators actually use, and add a Panel Setting key button on a maintenance screen so the corner press leaves the job for good.
An HMI panel that will not open its setup screens with a project loaded is almost never broken. The entry hides in a small square at the upper-left corner of the touch area, and it answers a sustained press, not the quick taps most people try first. On the panel family where this complaint is common, the documented hold is 3 seconds, and the instruction sits in an addendum that is easy to miss. This article runs the job in the order you meet it: hold the corner correctly, slide in from off the glass if a fingertip will not land, recalibrate with the contact your operators actually use, check the runtime version against the release that enlarged the corner area, and add a Panel Setting key button on a maintenance screen so the corner press leaves the job for good.
Why does the upper-left corner ignore taps when a project is loaded?
Because the entry is a press-and-hold, not a tap: the documented method is to press only the upper-left corner and keep it down for 3 seconds, and an addendum carries that instruction, so a reader working from the manual alone keeps tapping forever.
The activation zone is a small square, kept small so it does not interfere with the buttons on a loaded project screen. A tap lands and lifts in a fraction of a second, and the square wants a press that outlasts it. Hold times are not one number across the industry: at least one user guide for a building-automation touchscreen monitor prints a hold of at least 5 seconds and lets the duration be set. Read the entry procedure in your panel's user guide and its addenda, and use the printed value. The 3-second figure above is the documented value for the panel family this write-up covers.
How do I hold the corner so setup actually opens?
Put one fingertip in the extreme upper-left corner of the touch area and hold it still for 3 seconds without lifting: the setup screen should appear while you are still pressing, and if it does, the panel was never the problem.
- Place one fingertip in the extreme upper-left corner of the touch area.
- Hold it still for 3 seconds. One continuous press; do not lift and retap.
- Keep other fingers, the heel of your hand and a resting glove off the glass. One contact point only.
Check: the setup screen opens while you are still holding. If a clean 3-second hold produces nothing, the contact is missing the square, and the next section is the fix.
What reaches the square when a fingertip cannot?
Start just off the glass at the upper-left corner and slide slowly toward the screen center with steady pressure: this is the documented way into that small zone, and it lands even when a fingertip pressed straight down on the corner never does.
A finger that lands a few millimeters inside the corner sits outside the square, and a fingertip covers a lot of glass with a small spot that counts. The slide starts on the bezel just outside the display, drags diagonally toward the center and stops the moment setup appears. Note where on the glass it triggered: that point tells you roughly how far the square sits from where you had been pressing.
When a bezel lip, a gasket or a closed door blocks the corner, a fingertip may not reach the geometry at all. The end of a retracted ballpoint pen, or a narrow stylus, reaches the square with one small contact. Blunt tips only. A sharp point scores the touch film, and a scored film takes out the touch layer across the whole panel, so this one habit is what turns a service call into a replacement. Light pressure, rounded tip.
A gloved finger still registers on a resistive panel, but it covers more glass, and the corner square forgives little of that. Pen tip for the corner; gloves for everything else.
Check: repeat the corner press 5 times with your chosen tool. Five clean opens in five tries means access is solved for today, and the rest of the job makes it easy for the next person.
Which symptom points to which cause?
Map the symptom before you touch anything: a corner that never responds points to a hold too short or contact outside the square, a corner that works only sometimes points to the same square and a shaky landing, and touches that miss everywhere point to calibration drift.
| Symptom | Likely cause | Try first |
|---|---|---|
| Corner tap does nothing, ever | Hold too short, or contact lands outside the square | One continuous 3-second press, one contact point |
| Opens sometimes, not repeatably | Fingertip lands partly outside the square | Slide in from off the glass; switch to a blunt stylus |
| Corner unreachable behind a bezel lip or closed door | Enclosure geometry, not the touch layer | Blunt stylus; check the reach from the operator position |
| Every touch lands off target, not just the corner | Calibration offset | Recalibrate once you are inside setup |
| The corner needs many tries on every panel of this model | Small activation area in the installed runtime | Check the runtime version, then add the key button |
A button that fires as you release it is a different touch fault, and why an HMI touch button bounces after release covers that one separately.
How do I recalibrate so touches land where I press?
Run the touch calibration from inside setup and hold the stylus on each target's center until it is accepted and the next target appears: a stale calibration lands touches away from where the finger actually is, and the corner, the smallest target on the glass, suffers first.
Calibration routines walk a target across the glass, usually one per corner plus the center. Press the center, hold until the panel registers the hit, and let it move on. Then calibrate with the contact your operators carry: a calibration performed with a narrow stylus lands a bare fingertip differently, and the difference shows up exactly at the corner square. If the crew touches the glass through gloves, run the routine with a gloved finger.
Check: exit setup and count how many clean 3-second holds the corner needs. One is the goal. Do not rerun calibration in a loop chasing the corner: calibration moves touch positions, and it does not enlarge the activation square. If the corner still takes several tries, the two fixes below are what remain.
Does a newer runtime make the corner easier to hit?
Yes: a later release of the runtime enlarged the upper-left activation area by 50%, so a panel on an older build carries the smaller square and the harder entry; read the runtime version the panel reports and compare it against the release notes on the manufacturer's download page.
The update runs through the programming software under the manufacturer's own firmware procedure. Take the firmware only from the panel maker or its distributor, follow the documented update steps, and send the project again afterward if the procedure calls for it. Treat the bigger square as relief, not as the fix: it lowers the precision the hold needs, but it is still a hidden corner press that a technician performs at a panel, and the key button below is what removes the corner from the workflow.
Check: after the update, the same 3-second hold should open setup with a plain fingertip on most attempts. If the panel already runs the newest runtime and the corner still fights you, the key button is the whole answer.
How do I add a key button that opens setup on demand?
Put a key button on a maintenance screen that sends the Panel Setting key code: it opens the same setup screens from an ordinary on-screen button, so the corner press, the stylus and the sore finger leave the job completely.
- Open the project in the programming software and select the maintenance screen.
- Select Object -> Button -> Key Button and place the button on that screen.
- In the button properties, select Send Key Code.
- In the pulldown, select Panel Setting.
- Label the button in words a technician recognizes, then download the project to the panel.
Check: press the new button on the running panel. Setup must open on the first press.
That button is a door into panel settings, so it belongs on a screen operators cannot reach in normal running and behind the access levels your project already supports. HMI screen access control for a protected operator view walks through one way to build that protection.
Recommendation: on the next visit to any panel of this kind, fix the entry permanently. Run the calibration with the contact the operators use, and add a Panel Setting key button on a maintenance screen guarded by your project's access levels. Keep the 3-second corner hold as the fallback for a panel whose project you cannot edit, and wherever your own documentation prints a different hold time, follow that number.
Example: what does the whole fix look like on a mounted panel?
Scenario: the touch panel on a case sealer, mounted behind a closed enclosure door; the technician taps the upper-left corner 15 times and gets nothing, and the job below ends with setup opening on the first press of a new button.
The 15 taps explain themselves. At roughly 0.3 s per tap, a fair figure for a quick jab, that is 15 × 0.3 s = 4.5 s of total contact, but no single press lasts 3 seconds, so the panel never recorded one qualifying hold. The method was the fault, not the glass.
The fix, in order, with results:
- One fingertip in the extreme corner, held 3 seconds: setup opens on the second attempt.
- Slide in from just off the glass: lands on the first try, and the trigger point sits closer to the corner than the technician had been pressing.
- Calibration with a narrow stylus, one steady hold per target until each is accepted: afterward the corner opens on the first stylus hold and on the second bare-finger hold.
- Runtime check: the panel reports a build from before the release that enlarged the corner area by 50%. Taking the 50% as area, the side of the square grows by the square root of 1.5, about 1.22, so an illustrative 10 mm square, 10 mm × 10 mm = 100 mm², becomes about 12.2 mm on a side and about 150 mm² in area. The firmware update goes on the next planned stop.
- Key button: Object -> Button -> Key Button on the maintenance screen, Send Key Code, Panel Setting in the pulldown, labeled, project downloaded. First press opens setup.
Final pass, door closed: power-cycle and let the project load; the corner hold opens setup within two attempts using the pen tip; the new button opens setup on the first press; touches across the screen land on their targets; runtime and project versions go on the maintenance record. Hands-on time is about 15 minutes, plus the firmware stop when it comes due.
Decision: with the button in place and guarded, production runs no matter what the corner does. If the corner still needs three or more tries after the update, log it against the touch layer at the next planned stop, because a hold that used to work and no longer does points at wear, not at procedure.
Questions
Is there a startup keystroke that opens the setup screens?
No documented one. The two documented entry paths into setup are the corner press-and-hold and a key button that sends the Panel Setting code, so a procedure that depends on a keystroke during power-up will strand the next technician. Password protection belongs on the maintenance screen and its button, which the user levels in your project handle.
Can I enlarge the corner activation area from inside my project?
No. The square belongs to the runtime, so no screen object, script or project setting changes its size or position. Enlargements arrive with runtime releases, which is why the version check against the release notes comes before any conclusion that the touch layer has failed.
Does a glove stop the corner press from working?
A resistive touch screen registers a press by pushing two conductive layers together, so a gloved finger still counts as a touch. The problem is contact area: a glove spreads the press over more glass, and a small corner square is the least forgiving place for a wide contact. Use the blunt stylus for the corner.
Planning information, not legal or engineering advice. Rules differ by place: check codes and permits with your local authority and your licensed trades.