This is an old thread, But I also have the Somfy ZRTSI and have the same behavior. No way to control shade position. Zero brightness is all the way down and anything else is all the way up. I have no idea if the ZRTSI even supports an intermediate position. Does anyone know?
z-wave base node:
Indigo Z-Wave Version: 2022.2.1
Node ID: 55
Model: Static Controller
Model ID: 5A525400
Manufacturer: Somfy
Manufacturer ID: 0047
Protocol Version: 3.42
Application Version: 1.08
Model Definition Version: 0
Library Type: 7
Class Name: Static Controller
Class Hierarchy: 02 : 02 : 00
Command Class Base: 00
Command Versions: 20v1 72v1 86v1
Encryption Status: Not Supported
Multi-Endpoint Types: - none -
Multi-Endpoint Classes: - none -
Multi-Instance Counts: - none -
Features: - none -
Neighbors: 1, 3, 5, 7, 8, 9, 10, 12, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23, 27, 29, 31, 33, 35, 36, 37, 38, 40, 41, 42, 43, 46, 50, 54
Associations: - none -
Config Values: - none -