The Helvar interface is an extension which needs an extra license. This means if you want to use the Helvar interface you have to order the extension for license. The costs of the extension is fix fee.
The demo license includes the extension for testing purposes. So no special demo license is required if you want to test the Helvar interface.
Depending on the used Helvar routers, devices and groups, data points are subtracted from your license:
Routers:
1 data point for each used router
Groups:
2 data points for each used group
Devices:
Minimum 4 data points for each device
+ 1 data point if power consumption item is used (configurable)
+ 5 data point if emergency items are used (configurable)