on manual of Cerbo GX it is said you can use ET340 as gridmeter, second by second.
https://www.victronenergy.com/upload/documents/Energy_Meter_ET340/113406-Energy_Meters-pdf-en.pdf page 7
But what and how to do this when you want milliseconds (just to see the peaks during startup of a machine) ?
Did you check the datasheet for the energy meter? In there it tells you that the data refresh time is 1 second. It is not adjustable to 1000 times faster than that. These devices are not designed for the sort of thing you want.
If you need to gather information at such a high sampling rate then you need to use an energy analyser which is designed for the purpose.
