When ESS is configured to use a VM-3P75CT or VM-3P5A as the Grid Meter, what mechanisms exist to detect invalid measurements? For example, loss of communications, CT disconnection, CT wiring faults, or implausible readings. In each case, does ESS enter a safe mode that prevents uncontrolled export?
I currently have an ET112 which shuts down ESS if the RS485 is disconnected. I’ve also tried a long CT wire from the MPII which did not shut down ESS if the CT was disconnected.
So do the VM-3P75CT or VM-3P5A handle both LAN disconnect and CT disconnect?
In case of a typical parallel ESS (only AC in connected parallel to grid) the default fail safe would be the pass trough mode. (inverters and charging stops). So consumers will take power from the grid. But there are setup connection methods and or parameters like “Feed-in Excess” Setting or Essential load connections that completely change the behaviour. Please do read all relevant Victron documentation to perfectly predict the bahaviour for you specific case.
Thats likely due to “grid meter required” ticked to yes in the ESS settings, rather than the type of meter being used.
The same as with any other ESS grid meter including the MP2 own ACin measurments: None. The installer is responsible to check and make sure that, what is measured and displayed, is true.
With the above exception in the ESS settings (external meter required, and thus using internal metering or passthrough mode), theres no other system reaction to the grid meter disappearing/loosing communications. There might be secondary reactions, like AC-PV curtailment.
As for wiring faults, its a meter, how would it determine if whatever it measures can be true or not. Same for the ESS itself, if its getting fed wrong information then its going to act on that wrong information.
Probably no detection, since theres no such error on the error code list