VPIS means: Voltage Presence Indicating System in accordance with IEC61958.

It's purpose is to show if the cubicle is energized.

This is the standard SM6 indicator.

VDS means: Voltage Detector System in accordance with IEC61243-5.

The functionality of the VDS is to reliably test the voltage absence in the cubicle. The detector does not have integrated indication, but
only access to the information available on an electric connector block front panel.