Access EHmiLevel status in PLC logic (PLCnext eHMI)

PLCnext Engineer
1

Hello,

I am using PLCnext Engineer with the integrated HMI Webserver (eHMI).

Setup:

  • I have configured HMI users with roles EHmiLevel1 … EHmiLevel10

  • One user has EHmiLevel = 5 (Service)

  • When this user is logged in, access to a protected HMI page works correctly
    (Access / Visibility via ANY user level(s) ≥ 5)

PLC logic: In the PLC program I have a BOOL variable: Is_Service

If Is_Service = TRUE, the plant switches from automatic mode to manual mode
(e.g. actuators are no longer allowed to move automatically).

Requirement: I want the HMI tag / PLC variable Is_Service to be TRUE as long as at least one user with EHmiLevel ≥ 5 is logged in, and FALSE otherwise.

This should work:

  • without user interaction (no button click)

  • in the background

  • independent of the HMI client

  • including logout from another client

  • including automatic logout after session timeout (e.g. 20 minutes)

What I found so far:

  • EHmiLevel (e.g. EHmiLevel5) is available for HMI access rules, but
    it does not exist as a tag or system variable that can be used in PLC code.

  • I can set Is_Service := TRUE when opening the protected page and reset it on logout, but this solution fails if:

    • another HMI client logs out

    • the user is logged out automatically by timeout

Question: Is there any recommended or supported way in PLCnext Engineer / eHMI to:

  • link the current HMI user level (EHmiLevel ≥ 5)

  • to a PLC variable like Is_Service

  • centrally and client-independent?

Any best practice or official workaround would be highly appreciated.

Thank you!