The AVReporter contains two different types of virtual meter calculation. 1st type: Realtime Device Manager Modul (Desktop Manager -> AVReporter Settings -> Manage Plugin modules –> Realtime Device Manager Module) You can add devices to the expression. After initialization the service collects all common quantities from the devices and calculates it. Example: Namespace: Test namespace Device name: Test Meter Nr.1 Quantities: Active Power, Active Energy Delivered, Reactive Power, Reactive Energy Delivered, Reactive Energy Received Namespace: Test namespace Device name: Test Meter Nr.2 Quantities: Active Power, Active Energy Received, Reactive Power, Reactive Energy Received, Namespace: Test namespace Virtual meter: Test VM Virtual meter expression: [Test namespace-> Test Meter Nr.1]+ [Test namespace-> Test Meter Nr.2] The calculated quantities are: - TestVM -> Active Power <= Test Meter Nr.1->Active Power + Test Meter Nr.2->Active Power - TestVM -> Reactive Power <= Test Meter Nr.1->Reactive Power + Test Meter Nr.2->Reactive Power - TestVM -> Reactive Energy Received <= TestMeter Nr.1->Reactive Energy Received + Test Meter Nr.2->Reactive Energy Received You CAN NOT calculate with different type of quantities in this virtual meter !!! 2nd type: Advanced Virtual Meter Manager (Desktop Manager -> AVReporter Settings -> Manage Plugin modules –> Advanced Virtual Meter Manager) You can add quantities to the expression. Example: Namespace: Test namespace Device name: Test Meter Nr.1 Quantities: Active Power, Active Energy Delivered, Reactive Power, Reactive Energy Delivered, Reactive Energy Received Namespace: Test namespace Device name: Test Meter Nr.2 Quantities: Active Power, Active Energy Received, Reactive Power, Reactive Energy Received, Namespace: Test namespace Virtual meter: Test VM Nr.1 -> Active Power Virtual meter expression: [Test namespace-> Test Meter Nr.1 -> Active Power ]+ [Test namespace-> Test Meter Nr.2 -> Active Power] The calculated quantity is: - TestVM -> Active Power <= Test Meter Nr.1->Active Power + Test Meter Nr.2->Active Power Namespace: Test namespace Virtual meter: Test VM Nr.2 -> Calculated Value Virtual meter expression: [Test namespace-> Test Meter Nr.1 -> Active Power ]+ [Test namespace-> Test Meter Nr.2 -> Reactive Power] The calculated quantity is: - TestVM Nr.2 -> Calculated Value <= Test Meter Nr.1->Active Power + Test Meter Nr.2-> Reactive Power You CAN calculate with different type of quantities in this virtual meter !!!