When Placeholder Mode is active, HELIO does not connect to data sources. Instead, it displays the Placeholders for Offline Editing (Data Variable Property) that you have defined for your HMI data. This makes it the perfect mode for working without access to the PLC. For more information on how to define placeholders, please refer to Placeholders for Offline Editing (Data Variable Property).

Also make sure to learn about its counterpart, PLC Mode.