When a panel's static text object has no visibility tag, you cannot bind a bit to it. Write 0 to a lookup text object's assigned address to blank the text, or build one screen per machine mode and let the PLC load the screen number into the screen-selection register. The second path keeps 4x6 text and hides indicator lights too.
A static text object that has no visibility tag cannot be shown or hidden by a PLC bit: the field is absent from the object, and no amount of digging in its properties will produce it. The effect is still reachable from the PLC side, two ways. A lookup text object draws nothing while its assigned address holds 0, so the PLC hides a string by writing one value. Or you split the layout into one screen per machine mode and let the PLC load the screen number into the screen-selection register, which removes lights and graphics along with the text. The costs that decide between them are text size and PLC logic count. Both fixes, and the routing test that must pass before production, are below. For a status or notice board next to the machine, as distinct from the HMI itself, see shop-floor signage displays.
Can a PLC bit hide a static text object on an HMI panel?
No: on a panel whose static text object has no visibility field, there is no tag you can bind a bit to, so you emulate hiding from the PLC side, either by writing 0 to a lookup text object's address or by switching whole screens.
Stop hunting for the property; it is not buried two menus deep. The decision between the two fixes is what has to disappear. Text alone can move to a lookup text object and vanish on a value write. A block that includes indicator lights, or a layout built on the smallest text size the panel offers, needs one screen per mode with the PLC loading the screen number.
How do I check whether my HMI editor has a visibility option?
Open the object's properties in your installed editor and look for a visibility or show/hide entry, usually under an animations group; if the field exists, assign the tag there and none of the workarounds below is needed.
Editors place it in different spots, but every version works the same: the object tests one tag, and the tag decides whether the object draws. Set the bit in the PLC and the object follows. When two conditions must both be true before an object shows, do not fight a single-tag limit; build the combined result in one PLC tag and point the animation at it. That plumbing is covered in HMI object visibility with two conditions: use one PLC tag. Read the release notes for your editor version before building either workaround; feature sets move between releases.
How do I hide static text with a lookup text object?
A lookup text object draws the string its message database holds for the value at its assigned address, and when that address holds 0 it draws nothing, so the text is hidden until the PLC writes a nonzero message index.
What you need: the panel project, one spare PLC register for the assigned address, and the mode bit that used to drive the text.
- List every string the static text must show, and the state each string belongs to.
- Replace the static text with a lookup text object, and note its assigned address.
- Enter each string as a message in the object's message database, one entry per state.
- Allocate one PLC register for that address: write 0 to hide the text, write the message number to show it.
- Drive those writes from the same mode logic that used to drive the bit.
This path hides text and nothing else. An indicator light, a bitmap or a shape next to the string stays drawn, because the lookup object only ever controls its own string. If the thing that must disappear in Manual includes lights, build the per-mode screens instead.
What does the lookup text workaround cost?
The lookup path replaces your smallest static text with a bigger minimum: on this class of small panel, static descriptive text runs at 4x6 pixels while the smallest lookup text size is 6x6, and a single-bit show/hide becomes a value write that costs on the order of 20 PLC lines.
| What changes | What it does to the layout |
|---|---|
| Smallest lookup text size is 6x6 pixels against 4x6 static text | every replaced line grows 2 pixels taller; an eight-row stack grows 16 pixels |
| The address takes a value, not a bit | a one-bit show/hide becomes a message-number write per state |
| Text only | indicator lights and other graphics stay on screen |
On a roomy screen the size bump costs nothing. On a 3-inch panel already fitted with eight rows at the smallest static size, it is the whole layout. The logic cost lands in the PLC; the example below runs both numbers.
How do I build one screen per machine mode?
When the block to hide includes indicator lights or must keep 4x6 text, build one screen per machine mode: an Auto screen carrying the block and a Manual screen without it, and let the PLC change screens by writing the screen number to the screen-selection register.
What you need: a free screen number in the project, a request bit, the screen-selection register, and the mode bit.
- Copy the crowded screen, delete the block that must hide on the copy, and note both screen numbers.
- Point the panel's navigation at the PLC: configure the function key or on-screen button to write a request bit instead of performing a direct screen change.
- Allocate the screen-selection register the panel reads for screen changes.
- Write one rung per mode: with the request bit on and the machine in Auto, load the Auto screen number into the register; a second rung does the same for Manual.
- Add a third rung that reloads the register whenever the mode bit changes while an operator is already on a screen. Skip it and the old screen stays up after the machine returns to the other mode.
- Download the PLC program and the panel project.
The write itself, tag type and addressing included, is covered in write a screen number from a PLC to the panel register. If the panel treats a write that repeats the screen already showing as no event, the retrigger fix is in PLC to panel screen switch register: retrigger the same screen. The price of this path is upkeep: two screens carry the same layout, so every later change is made twice.
How do I keep operators off the wrong screen?
Use a button that changes screens on the panel only for destinations that are safe in every machine state; for any destination that depends on mode, use a regular button that writes a PLC bit and let one rung per case load the screen number into the screen-selection register.
The split puts the destination decision where the mode lives. A button that changes screens on the panel cannot ask the PLC anything, so it belongs only on doors that are open in every state. A conditional destination goes through the PLC, and an operator pressing navigation buttons at random cannot land on a screen the mode forbids. The on-panel side, button types included, is covered in set up HMI screen navigation with change screen buttons.
Example: how do I hide eight motion-step labels on a 3-inch screen?
On a 3-inch panel showing eight motion steps as indicator lights with 4x6 labels, the lookup path grows the label stack from 32 to 48 pixels tall, so the fix is two screens: Auto keeps the block, Manual drops it, and the PLC routes.
The layout: eight motion steps listed on the main screen, each step an indicator light whose text and color change as the program walks the steps, descriptive labels at 4x6 pixels. In Manual, the whole block must disappear.
Try the lookup path first. Each label grows from 4 to 6 pixels tall, 2 pixels per row. Eight rows: 8 x 2 = 16 pixels added, so the stack goes from 8 x 4 = 32 pixels to 8 x 6 = 48 pixels tall, half again as high, and the fit that made the screen work is gone. The lights stay drawn too, because lookup text hides text only. And the conversion carries the PLC cost: about 20 added lines for this list.
Build the screens instead. The Auto screen keeps all eight lights and their labels. The Manual screen omits the block. The function key writes a request bit, two rungs load the Auto or Manual screen number by mode, and a third reloads the register on a mode change. That is 3 rungs of routing logic against the lookup path's added lines, with the original text size intact and the lights removed along with the text.
Recommendation: Use the lookup trick as the quick fix only when text is the only thing to hide and the bigger minimum size still fits the layout. When the block includes indicator lights, or the labels run at the smallest static size, build one screen per machine mode and route navigation through the PLC screen-selection register, with the mode-change reload rung in place before the machine runs again.
How do I test the screen routing before production?
Prove the routing with the machine down: set each mode, press the routing button, and watch the screen-selection register, which must hold the expected screen number after every press and must never hold a number for a screen that does not exist in the project.
- Set the machine to Auto and press the routing button: the Auto screen loads with all eight step indicators.
- Set Manual and press the same button: the Manual screen loads without them.
- Toggle the mode bit while sitting on each screen: the panel follows without another press.
- Press every other navigation button in both modes: recipe-button destinations always load, and conditional destinations land on the mode-correct screen.
- Watch the screen-selection register after each press: it holds the expected screen number and never a number with no screen behind it.
When all five come back clean, no combination of presses can put a mode-wrong screen in front of an operator. To lock navigation altogether while a mode or bypass tag is on, see lock HMI screen navigation while a bypass tag is on.
Questions
How many display strings can one lookup text object switch between?
A lookup text object draws the string stored for the value at its assigned address, and one object can be configured with up to 255 messages. An eight-step list needs eight entries plus the hidden state, nine in all, so capacity is never the constraint in a layout like this.
My editor does have visibility animations. Can more than one condition drive one object?
Yes. Give the visibility animation one integer tag and let the PLC build the conditions into that tag's bits, one bit per state, and have the object test a single bit. Folding the logic into one PLC tag sidesteps the editor's single-tag limit entirely, and the object still sees one ordinary value.
Can I hide static text by recoloring it to match the background?
It looks hidden, but the object is still alive in the touch layout. On a small panel an invisible object can catch a touch meant for a neighbor or overlap one, and any later color-scheme change brings the ghost text back. Use the lookup write or the per-mode screens instead.
Planning information, not legal or engineering advice. Rules differ by place: check codes and permits with your local authority and your licensed trades.