The reev EMS enables dynamic load management, PV surplus charging, and grid-friendly control of charging infrastructures. Below you will find the key technical information regarding integration, compatibility, configuration, and operation.
1. Compatibility of Meters & Protocols
The reev EMS supports only energy meters that communicate via Modbus TCP/IP.
Meters such as the Carlo Gavazzi EM210, which operate via RS485/Modbus RTU, cannot be used directly.
A full list of compatible meters can be found here.
2. Topology & Integration
The reev EMS always reads measurement data via Modbus TCP/IP. A Teltonika router is used as the IoT gateway, which reads phase currents and active power values directly from the energy meter. The charging stations communicate separately with the reev backend via OCPP — no Modbus connection is established with the charging stations.
An IoT gateway is always required when using dynamic load management or PV surplus charging, even if the charging stations already connect to reev via built-in SIM cards. The only requirement is that the gateway is located in the same network as the meter; merging the network with the charging stations is not necessary.
Recommended hardware: Teltonika RUT241 or any comparable device with Modbus TCP & RMS support.
Note: When using a reev SIM card, no port forwarding is required; RMS should be enabled with default settings.
3. Import/Export & PV Surplus
The reev EMS supports automatic import/export detection at the grid connection point. The system uses the measured polarity of the power values to detect PV surplus and apply it for charging. The EMS always relies directly on the phase-accurate current and power values provided by the meter.
If loads are unevenly distributed across phases, a configurable imbalance protection may activate (default: up to 20 A difference allowed). This can be disabled if desired.
PV surplus charging can be enabled globally and reacts immediately to changes in PV output. Due to the fast control behavior, no hysteresis is applied. With highly fluctuating PV output, this may lead to more frequent charging interruptions. Group-based PV authorization is currently not possible; the setting always applies globally to the entire infrastructure.
A hysteresis function is expected to be implemented in 2026.
4. Configuration & Operation
The reev EMS allows flexible definition of grid structures — for example, a main distribution board with a defined total current limit and subordinate sub-distributions or charging groups. Current limits can be set at both group and charging point level. Priorities can also be assigned per charging point, user, or user group.
In case of an error — such as missing meter readings or interrupted communication — the TxDefaultProfile of the charging stations applies automatically. This profile is sent via the reev EMS system and determines whether charging continues with reduced current or is completely stopped. For AC charging, 6 A per charging point is set as the default. This value can be adjusted if needed.
Note: For optimal performance, we recommend keeping the firmware of the charging stations up to date.
5. Commissioning & Setup Effort
After installing the meter and the gateway, network connectivity is established and RMS is activated. Afterwards, the reev EMS can be activated in the reev portal and the system topology can be configured.
The final step is carried out by reev Support: We configure the gateway, activate dynamic load management, assign the energy meter within the system, and enable PV surplus functionality if requested.
6. Additional Information & Installation Guides
Further information about the reev EMS can be found in the reev Help Center. Installation guides for PV integration and dynamic load management are also available.