Known limits
17 min readTroubleshooting
Known limitations for Live, communication and redundancy, remote monitoring and TV, script engines and installation. Each limitation states what to do.
What this topic contains
The following are behaviors that the product does not cover in this version, either deliberately or not yet. Each row has been verified against the code and the user interface. The limits of the communication drivers are in their own topics (Connection diagnostics).
Design and operation: summary by section
The limits below are described in detail in the relevant topics; this table collects them at a glance. The limits of the drivers themselves (such as unsupported data types) are in the driver topics (Drivers).
| Field | Limit | Details |
|---|---|---|
| Acquisition cycle | On change is not a separate read mode; Live converts a cycle with a duration of 0 to 1 s. For fast reading, select a cycle such as 100 ms. | Cycles |
| Connections | Two connections cannot be opened to the same device endpoint (same address, port and endpoint parameters); the same IP is allowed with a different driver, port or parameter. The second (backup) CPU address is entered only in S7 drivers. | Connections table |
| Tag errors | The tag error message of the driver is not shown in Live; only the connection state and the last error message of the connection are visible. | Connection diagnostics |
| Animations | For control objects (trend, alarm, recipe, report, camera, Screen window) Live applies only position, size and visibility; the Flashing, Opacity (%) and Angle bindings have no effect. | Animations |
| Events | The Release event runs if the mouse button is released over the object; it does not run if it is released outside. Jog bits of the form “1 on press, 0 on release” can remain at 1. | Events and functions |
| Controls | The Close button setting of the Screen window and the Users editable setting of the User view have no effect in Live. | Controls |
| Menus | An unauthorized menu item is drawn inactive and no warning appears; buttons that do not fit in the horizontal toolbar are cut off; hiding a screen from the Navigation menu does not block access to it. | Menu design, Navigation menu |
| Alarms | A Help text cannot be entered for an analog alarm (it exists only for discrete alarms). | Alarm definition |
| Reports | The Record time switch in Additional fields has no effect; every record always carries a time. | Report design |
| Users | The Level value of the group is not used in Live. A deleted authorization makes the object bound to that authorization open to everyone. | User administration, Applying authorizations |
| Tasks | If the On change cycle is selected in a cyclic task, the task is never scheduled. | Scheduled tasks |
| Panel design wizard | It does not produce circuit diagrams, cable lists or drilling / cutout drawings; its output is a 3D scene, a 2D view, a bill of materials and Excel. The heat calculation is a preliminary sizing based on typical losses. The terminal area, vertical ducts and the heater cannot be moved manually; the MCC drawer and the air circuit breaker can only be selected. The bill of materials contains no order numbers. | Panel design wizard |
| Siemens / ABB panel equipment | The objects are drawn to resemble the products but carry no logo, brand lettering or order number; some faces and dimensions are approximate. | Siemens and ABB panel equipment |
| Device configuration | Station name and Description are not used in Live; with a single station, Computer name only gives a warning and does not prevent Live from starting. | Device configuration |
Live
| Limit | What to do |
|---|---|
| Live runs only one project at a time. When the project is changed, monitoring, alarms and logging stop until the new project is opened. | Open the projects one after another (Change project…); you cannot run two at the same time. |
| A change made in Studio is not reflected immediately in a running Live. | Upload the project to Live and reopen the project in Live. |
| In local Live there is no theme switch in the system menu. The theme comes from the Default theme setting in the project: Light, Dark or Automatic (by time of day) (dark between 19:00 and 07:00). | Select the theme in Studio under Live settings. A user monitoring from a browser has their own theme button. |
| The on-screen keyboard is available only in the Turkish Q layout and works only in the local Live window. | If another layout is needed, use a physical keyboard. |
| The window, keyboard and additional application settings do not apply in browser monitoring or on the TV. | Consider these settings only for the Live computer. |
| The event log, the alarm records and the recipe transfer log are not deleted automatically. | Watch for the disk filling up; back up and delete old monthly files (Files and folders of Live). |
The passwords of connections that require a user name and password, and the PFX passwords of MQTT client certificates, are stored as plain text on the computer in the file baglanti_sifreleri.json. | Restrict access to the .veri folder to authorized Windows users. |
| The connecting state is not shown in the connection status; no connection is displayed until the connection is established. | Wait for the error message to appear (Connection problems). |
Communication and redundancy
Limitations of serial Modbus, MQTT 5, the S7 backup PLC and the redundant server pair. Other driver-specific limitations are described in the driver topics.
| Limit | What to do |
|---|---|
| Modbus RTU / ASCII has no flow control, and DTR / RTS are off; there is no setting for RS-485 converters whose direction is switched with RTS. Test connections does not test serial connections. There is no broadcast (device address 0). | Use a converter with automatic direction control; test the serial connection in Live (Modbus serial line). |
| Connections using the same COM port cannot have different serial settings; requests on the line are sent one after another. | Set all devices on the line to the same baud rate and parity; assign slowly changing values to a long cycle. |
| MQTT supports only clean sessions; the MQTT 5 AUTH packet, Will message, topic alias and shared subscription are not used. TLS 1.2 only. | Configure the server so that it works without these features (MQTT driver). |
| The backup PLC is available only in the S7 drivers. If the connection to the active CPU is lost, the connection briefly shows no connection and writes pending at that moment are rejected. Live writes only to the master CPU. | Keep the data of the backup CPU in sync on the PLC side (Automatic switchover to the backup PLC). |
| In a redundant server pair, the Windows Firewall rule for the redundancy port is not added automatically. | Add the inbound rule manually on both computers (Redundant server pair). |
| If the master Live is running but its PLC connections are lost, the master role does not pass over automatically; the switchover only takes place when the other Live does not respond. | Use Hand over master role… in the system menu. |
| If no connection has an arbiter address and the network between the two computers is lost, both Live instances become master and both write to the PLCs. | Define an arbiter address in at least two PLC connections. |
| On the standby server, event functions that run scripts, tasks, manual report records and recipe transfer by script do not work. Additional applications start on both computers. | Do these tasks on the master; choose additional applications accordingly. |
| When the role changes, the screen is reloaded in both Live instances: open windows close and the operator logs on again. When a browser viewer switches to the other server, it logs on again there. | Inform the operators about this behavior. |
| Event lines written on the standby while the master cannot be reached stay local and are not sent to the master later. The traffic between the two Live instances is unencrypted HTTP. | Set up the two servers on a trusted network with a reliable connection between them. |
Remote monitoring and TV
| Limit | What to do |
|---|---|
| Browser monitoring uses plain HTTP; there is no HTTPS. Passwords and data are not encrypted. TV addresses are password-free by default. | Do not expose it to the internet; use a VPN (Remote access over VPN). If it is not needed, turn off TVs watch without password. |
| The viewer is read-only by default: there is no control, alarm acknowledgment or setting changes. Remote control is available only to browser users with an authorization group; they cannot change settings or close the program either. | If needed, switch on remote control; do the other tasks on the Live computer. |
| In remote control, object, screen and function authorizations are applied in the browser; when accepting an action, Live checks only the session, the authorization group and that control is turned on. | Grant control authorization only to people you trust and to the group that needs it; use a VPN. |
| The same browser user can connect from only one computer (IP address) at a time; there is no setting to turn this off. Computers behind the same NAT / VPN gateway count as one computer. | Create a separate browser user for each person. |
| Tasks, simulators and drivers do not run in the browser or on the TV. Scripts do not run in a read-only viewer or on the TV; in a remote control session only the scripts of events started by the user run in the browser. | Put the logic in Live; the viewer sees the result. |
| The port must be in the range 1024 – 65535. If another program is using it, the server is opened on a random port bound to this computer only. | In Studio, change Remote monitoring › Port. |
| 5 failed logins from the same address lock that address for 60 seconds. | Wait, or correct the password. |
| A maximum of 8 TVs can be defined; the display sequence has at most 40 rows; the duration is 5 – 3600 seconds. Pop-up window and template (fixed area) screens and the fixed upper / lower areas are not shown on the TV. | Design full screens for the TV. |
| The second-display TV requires a display that is used neither by Live, nor by the multi-monitor setup, nor by the additional monitor pages; otherwise the TV window does not open. | Monitor the state in Live from the system menu › Remote monitoring… window (Multi-screen and TV). |
| Multi-screen (side by side, stacked, grid) is applied only in full screen. | Leave Open in full screen on. |
| The Separate page on each monitor layout has not been tested end to end on two real monitors. | During the first installation, test screen changes, log on / log off and writing a value on each monitor. |
| Remote control and the screen trail of browser users have not been tested end to end with a real Live and real browsers on the network. | Test on site on first use; check the event log. |
Project database
| Limit | What to do |
|---|---|
| In the SQL Server Express instance installed by the setup, only the Windows account that ran the setup is an administrator; the instance is closed to the network. | If Live runs under another account, grant that account permission in SQL Server; for a shared database, enable network access in SQL Server (Project database). |
| SQL Server 2025 Express is not installed on Windows 7 or on 32-bit Windows. | Live continues to write to the local file; use an SQL Server on another computer. |
| There is no separate window in Live that shows the database state. | Check the sistem records in the event log and the program log. |
| The project database has been tested in Live's own tests (LocalDB); it has not been tested end to end with a real installation. | On first use, check that rows arrive in the tables. |
OPC UA server, notifications, performance reports, AI
The limits of these features are in their own topics. Summary for planning:
| Limit | What to do |
|---|---|
These three features are separate license items (FV-OPC, FV-NTF, FV-PRF). Without the license, Live runs; only the feature does not work. | Option licenses |
| The OPC UA server, notifications and report plans work only while Live is running. If Live is closed, no notification is sent and no report is produced at the planned time. | Use them on a computer where Live stays open all the time (OPC UA server, Notification center, Report plans). |
| Performance report values are calculated from the archive: for a tag that is not archived, the report shows no data. | Add the tags you will bind to the report to a data archive. |
| The AI package (model and server programs) is not included in the setup and is downloaded separately; the assistant does not work until the package is installed. | AI Assistant |
Scripts
The script engines are the product's own engines and support a subset of the languages. The full scope is given in the language topics (VBScript, JavaScript, C, Python).
| Limit | What to do |
|---|---|
| A VBS, C or Python call can compute for at most 30 seconds; waiting, database and window times are not counted. There is no limit in JavaScript: an infinite loop can lock up the interface. | Do the waiting with a scheduled task, not with a loop. |
| In VBS, C and Python, a call that arrives for the same trigger while the previous call is still running is skipped. JavaScript has no such check. | Lengthen the task cycle (Script and task problems). |
| There are no breakpoints or step-by-step execution. JavaScript has no reference panel either. | Print a trace (Trace, printf, print) and look at the event log. |
VBS: there is no Execute, ExecuteGlobal, Eval, GetObject, GetRef, On Error GoTo etiket or Resume; Class_Terminate is not called. | Use Err with On Error Resume Next. |
VBS and Python: there are no HMIRuntime.Alarms, AlarmLogs, DataLogs, Logging or MenuToolBarConfig; generating and acknowledging alarms and archive logs cannot be done from a script. | Generate the alarm with a definition bound to a tag; do the logging with an archive definition. |
C: bit fields, long long / __int64, K&R parameters, goto to a label in an inner block and named initializers produce a compile error; scanf, gets and getchar do not exist; a real DLL cannot be loaded. | Adapt the code to these rules. |
Python: async / await, eval, exec, threads, network access and third-party packages (numpy, pandas, requests …) are not available. | For database work, use ODBC with pyodbc. |
The database connection is stateless: there are no transactions and no temporary tables. WScript.Shell.Run starts the program but does not wait for it to finish. | See the topic Database access. |
| The database, program execution and file permissions are off by default. These functions do not exist at all in JavaScript. | Turn on Script permissions only in a project you trust; use VBS, C or Python for these functions. |
Convert (TIA Portal conversion)
| Limit | What to do |
|---|---|
| Classic panels and WinCC Unified are read only on a computer with TIA Portal V17 – V20 installed (V18 or later for Unified). On a computer without TIA, only compiled WinCC Professional stations are read from the project folder, and symbolic tag addresses are not resolved. | On a computer with TIA Portal, create a package with Also keep the export package; open the package on the computer without TIA Portal (Convert). |
| Tags in optimized data blocks have no absolute address; the S7 driver cannot read them. | Use the OPC UA mapping of Convert, or switch the data block to standard access and convert again (Optimized data blocks). |
| Alarm definitions are not transferred for classic panels; recipes, users and archives are not transferred for any family. In WinCC Professional, alarms are read from the WinCC SQL Server instance; if the instance cannot be reached, they are not transferred. Faceplates and custom controls become placeholders. | Define these in Studio; the list of items not transferred is in the conversion report. |
Installation
| Limit | What to do |
|---|---|
| The supported systems are Windows 10 and 11. The setup program also opens on Windows 7 SP1, 8 and 8.1, but the FabyaVision programs have not been tested on these systems. | Update the computer (Installation). |
Setup installs a missing .NET Framework 4.8 and WebView2 Runtime with the Microsoft installers included in its own files. On 32-bit Windows 10, or if Data\Prerequisites is missing, WebView2 requires an internet connection; if it cannot be installed, the programs do not open until the Runtime is installed. | Copy the complete Data folder, or copy the Evergreen Standalone Installer from another computer and install it. |
| Information that a full version license has been revoked or transferred is received only when the program goes online; the license on a computer that never goes online keeps working. | Details: Online license check. |
| The setup program is not signed; Windows SmartScreen may show a warning. | After making sure of the source of the file, select Start anyway. |
Uninstalling deletes the logs folders and the two settings files. | Before deleting, copy the logs needed for support (Log files). |