The HMI editor's zoom percentage changes only how large the project canvas is drawn on your PC monitor. The project's pixel dimensions are fixed by the operator panel selected in project setup, so a small canvas at 100% zoom on a 22-inch desktop monitor is correct. Change resolution only by changing the target panel in project setup, then rescale screens with the software's documented resize option.
At 100% zoom an HMI editor draws the project canvas at its true design size, and a panel-sized canvas is genuinely small on a desk monitor. That is correct behavior, not a setting to hunt for. Zoom changes the drawing on your workstation; the project's pixel dimensions are fixed by the operator panel selected in the project setup, and the panel on the machine renders exactly those pixels. No zoom value raises panel resolution. The only real resolution change happens in project setup, next to the target device selection, and the numbers below cover both cases.
What zoom changes and what it leaves alone
Zoom is a drawing multiplier. Set 170% and the editor repaints the canvas 1.7 times larger on the monitor; every object keeps its stored coordinates, so a button placed 40 px from the screen edge is still 40 px in the project file and still lands 40 px from the edge at runtime. The runtime panel never sees your zoom value.
One line of HMI documentation puts the principle plainly: "The screens in a project represent the physical size of the HMI device." The help page for changing a project's target HMI device carries that line, and every editor follows the same rule: the canvas is the panel. Your desk monitor is a second display with its own pixel grid, and the two share only the project file. The reverse arrangement, putting an operator panel on a desk as the monitor for a PC, has its own answer.
A second viewing aid stacks on top of zoom: the operating system's display scaling. Many workstations run 125% or 150% scaling, which enlarges every application window equally. Like zoom, it changes nothing inside the project.
Example: an 800 × 480 canvas on a 22-inch monitor
Take a project that targets a compact operator panel with an 800 × 480 canvas, a common small-panel format. The workstation is a 22-inch monitor at 1920 × 1080, with display scaling at 100%.
- Pixel density: √(1920² + 1080²) = 2203 px across the 22-inch diagonal, so 2203 ÷ 22 ≈ 100 px per physical inch.
- At 100% zoom, 1 project px is drawn as 1 monitor px. The canvas measures 800 ÷ 100 = 8.0 in wide by 480 ÷ 100 = 4.8 in tall.
- The monitor's working area is 1920 ÷ 100 = 19.2 in wide by 1080 ÷ 100 = 10.8 in tall. The canvas covers 8.0 ÷ 19.2 = 42% of the width and 4.8 ÷ 10.8 = 44% of the height. That is why 100% feels small: it is the honest size of the panel.
- At 170% zoom the drawing is 800 × 1.7 = 1360 px by 480 × 1.7 = 816 px, which is 13.6 in by 8.2 in. That fits the 19.2 in by 10.8 in desktop with room for tool panes, and the 8.2 in short edge sits close to the 8.5 in height of a landscape 8.5 × 11 in sheet, which is why 170% feels right on the desk.
Nothing in the project moved between those two cases. The panel still has 800 × 480 px to draw on at runtime; you changed the picture on the desk, and only that.
Where the resolution actually changes
The canvas size is a property of the target device, held in the project's configuration. One package keeps it on a Panel Manager screen that configures global settings for the project; others keep it in project or device properties. The name varies, the location is always project setup, and zoom is never part of that dialog.
When the hardware itself changes, the documented workflow is to change the target device first, then rescale the screens. Vendors document the pieces differently: some offer a Screen Scaling option at the moment you change the target device. One package resizes selected screens with a context-menu command named Resize to Display. For moving a project from a 15-inch device down to a 9-inch one, a documented route opens Options > Settings > Visualization > Resize screen and chooses Fit to screen. Some of these steps rescale object positions to the new canvas, others keep coordinates and clip, so read the prompt before accepting it and treat any conversion warning as an order to review the layout.
When to zoom and when to go back to 100%
Zoom up for drawing work: small text, tight row spacing, aligning objects a few pixels apart. On the monitor from the example, 170% is a comfortable working scale for an 800 × 480 canvas.
Return to 100%, or to a zoom where the canvas matches the panel's real physical size, when you judge how much content the operator can take in at the machine. A canvas that fills a desk monitor fills a fraction of the panel, and objects sized to look right at 170% on a 19.2-inch-wide desktop can be unreadable at the 4.8-inch-tall truth of the panel. If the real complaint is that text reads too small on the panel, that is a text size problem with its own cause and fix, separate from resolution. And when one layout has to live on two different panel sizes, the pixel math behind that is covered in why two HMI panel sizes can share one layout in pixels.
How to check either change
Zoom-only session: open the project setup, check the selected panel is unchanged, save, download to the panel. The runtime result is identical, pixel for pixel, because the project's pixels are identical.
Target-device change: work on a saved copy, change the device in project setup, run the software's resize or Screen Scaling step, then inspect every screen on the real panel before the machine returns to production: labels not clipped, edge objects visible, touch targets where the operator expects them, text legible at the operator's standing distance.
Recommendation: Treat zoom as a desk setting and resolution as a project setting. Keep the project at the panel selected in setup; an 800 × 480 canvas at 100% zoom is correct even when it covers under half of a 22-inch monitor, and about 170% zoom is the comfortable drawing scale for that canvas on that desk. Change resolution only through the target device in project setup, using the software's documented resize or Screen Scaling step, then verify every screen on the real panel before startup.
Questions
Does editing at 170% zoom make the screens sharper on the panel?
No. Zoom scales the editor's drawing on the workstation monitor only, and the downloaded project is the same pixel grid whatever zoom you used. Sharpness at the machine comes from the panel's pixel pitch and the operator's viewing distance, and no editor setting moves either. If text looks soft on the panel, look at text size in project pixels, not at zoom.
Why did the whole editor grow when a Windows setting changed?
That is the operating system's display scaling, commonly set to 125% or 150% on high-density monitors. It enlarges every application window equally to keep system text readable. Like editor zoom, it is a viewing aid: object coordinates, canvas pixels and the selected panel are untouched. Two independent multipliers sit between your project and the glass, and neither one is a resolution change.
Can I enter a custom canvas size that matches my desk monitor?
There is nothing to match. The canvas exists to equal the target panel's native pixel grid, and the panel's resolution is fixed by its hardware. The sizes the software offers are the ones the selected hardware supports, so a custom size would produce a project no panel can display. If the desk view is too small, change zoom; if the panel is wrong, change the target device.
Why do objects keep their exact pixel positions while I zoom?
The project stores each object's position in project pixels, and zoom multiplies the rendered drawing uniformly at view time. Positions, sizes and spacing stay proportional at any zoom, which is the point: what you lay out is what the panel shows, in panel pixels. A zoom that rearranged objects would make the desk view disagree with the runtime view, which is the fault this design prevents.
What canvas size should I plan a small panel project around?
The selected device's own canvas, read from the project setup screen. Small operator panels commonly run 800 × 480 or 1024 × 600, while larger ones reach 1024 × 768 or 1920 × 1080. Place objects inside the canvas the software shows for the device, and remember the panel can display only pixels it physically has. Design in project pixels and check the layout at the panel.
Planning information, not legal or engineering advice. Rules differ by place: check codes and permits with your local authority and your licensed trades.