Block the HMI system setup screen with a system tag

The two system tags that touch setup

The tag browser in the programming software lists system tags the panel firmware exposes. Two of them concern setup:

• SYS DISABLE USE F1+F5 SETUP is the lockout. Set it ON and pressing F1 and F5 together no longer opens the system setup screen.
• SYS GO TO SETUP MENU is navigation. A button wired to this tag commands the panel straight into setup, which is the opposite of a lockout. Keep it off operator screens.

Confirm the exact spelling in the software version your panel runs. Version 2.30.0.0 is the build these names shipped with. If you are not sure which build is installed, verify the installed HMI software version first.

Why a hidden button or a pop-up is not the fix

The usual workaround is a project screen that needs a 5-second hold to reach, plus a pop-up warning that says the screen is off limits. That works by secrecy. Anyone who learns the hold still gets in, and the panel's own F1 and F5 keys sit outside the project entirely, where no project button can reach them. The disable tag removes the entry path instead of hiding it: with the bit ON, F1+F5 does nothing at run mode.

If your setup entry is a hidden touch target that operators hit by accident or cannot open at all, that is project logic, covered separately in why taps never open the HMI hidden setup screen.

What you need

• The project file and the matching programming software, open on the maintenance PC.
• A saved copy of the working project, so the edit can be rolled back. Save first and edit second, the same discipline as backing up HMI recipe files before a project download.
• A maintenance-only screen in the project, or one spare pushbutton on an existing maintenance screen.
• The panel maker's hardware manual, open to the system setup screens chapter, so you can check behavior for your model.
• A download path you have already used once: cable, address, procedure. You will run it again with the lockout on.
• A maintenance window. Budget 30 minutes for the edit, download and both checks on the first panel.

Set the tag from a maintenance screen

1. Save a copy of the working project.
2. Open the tag browser and find SYS DISABLE USE F1+F5 SETUP, spelled exactly as printed here and in your manual.
3. Add a pushbutton object on the maintenance screen whose action sets that tag ON, and label it for maintenance use.
4. Search the project for any button wired to SYS GO TO SETUP MENU, and remove it or move it behind maintenance access.
5. Download the edited project with your normal procedure.
6. On the panel, press the maintenance button once, then try F1+F5 at run mode. Expected result: nothing opens.

Keep the maintenance screen out of the operator navigation. The lockout is only as strong as the reach control on the button that sets it.

Test a power cycle and a download before rollout

The manual documents the tag; it does not promise that the disable survives a power-up. Treat persistence as something to check on your own panel, in a stop of about 15 minutes, before anyone copies the project further:

1. With the lockout ON, cycle panel power once.
2. At run mode, press F1+F5 again. If nothing opens, the lockout held.
3. Run a planned project download from the maintenance PC, using the saved copy. Never test recovery by erasing user memory.
4. If your panel's service procedure normally passes through the system screens, run the whole procedure with the lockout ON and confirm every step still works.

If the panel will not take a download with the lockout on, restore the saved copy, leave the tag unset, and settle service access with the panel vendor before deploying. A panel you cannot service leaves the line interface down for every fault that needs setup, which costs more than an operator reaching a clock screen.

Rule out one related fault while you are here: a project that vanishes at power-up is a different problem from a lockout that clears, and it is covered in HMI panel loses its project after a power cycle.

Example: locking F1+F5 on a line panel running software 2.30.0.0

Inputs. A packaging-line panel with a complete PLC program, whose operators reach the system setup screen at run mode by pressing F1 and F5 together; that entry path is the panel's documented system screen access. Programming software version 2.30.0.0, the build these tag names shipped with. Two setup-related system tags in the tag browser: SYS DISABLE USE F1+F5 SETUP and SYS GO TO SETUP MENU. One maintenance screen to hold the lockout button. The test plan budgets one power cycle and one planned download inside a 30-minute maintenance window.

Rule in words. Setting SYS DISABLE USE F1+F5 SETUP ON removes the F1+F5 entry path at run mode. SYS GO TO SETUP MENU only commands entry into setup, so it never blocks anything. Persistence is checked with one power cycle; service access is checked with one planned download from a saved copy.

Arithmetic. The pre-rollout test is one of each check: 1 access test at run mode + 1 power cycle + 1 access test after power-up + 1 download test = 4 checks. The old 5-second-hold workaround leaves 1 known entry path open to anyone who has learned the hold; the tag leaves 0.

Result. F1+F5 opens nothing at run mode and again after the power cycle. The planned download lands from the saved copy with the lockout ON, and the ordinary screens still change and write to the PLC. All 4 checks fit inside the 30-minute window.

Decision. With all 4 checks passed, copy the project to every other panel on the line that runs the same build. If the after-power-cycle check fails on a panel, that build does not hold the lockout: reapply the tag from the maintenance screen at each restart, or get a documented persistence setting from the vendor, before any rollout. If the download check fails, restore the saved copy and leave the tag unset until service access is settled.

How to check it worked

Work down this list on the panel before you call the change done:

• F1+F5 at run mode opens nothing.
• After one power cycle, F1+F5 still opens nothing.
• The ordinary screens still change, and the panel still writes to the PLC. Check the writes with the bench test in operator panel PLC link setup: test writes before motion before anyone runs the machine.
• A planned download from the maintenance PC lands with the lockout ON.
• The maintenance screen with the lockout button stays out of operator navigation.

If F1 and F5 stop working entirely after a software upgrade, with no lockout set, that is a panel fault, not a project problem, covered in fixing an F1 F5 lockup after an upgrade.

The decision

Lock the machine HMI to maintenance and let it run untouched. If the line also needs a status board the whole crew can read, a separate shop-floor display carries that job without anyone touching the panel's project.

Recommendation: Set SYS DISABLE USE F1+F5 SETUP from a maintenance-only button, run one power cycle and one planned download on one panel, and copy the project to the rest of the line only after all 4 checks pass. Keep the maintenance screen out of operator navigation and a saved project copy on the maintenance PC. If the post-power-cycle check fails on your build, reapply the tag at each restart and ask the vendor for a documented persistence setting before any rollout.

Questions