Multi Device Control (MDC) is used to control multiple battery storage units within a single system. A central device coordinates all integrated components and ensures that all storage units operate in a coordinated manner.

System architecture and distribution of tasks 

An MDC network consists of one MDC host (PLENTICORE G3 inverter) and up to two MDC clients.

The MDC host acts as the central control unit and monitors and regulates all MDC-compatible devices within the home network. To operate more than one battery storage unit, the paid product extension ‘Battery Control with MDC’ is required on the host. Without this activation, only the battery connected directly to the host can be used.

The battery with the largest usable storage capacity must always be connected to the MDC host. The battery with the largest usable storage capacity must always be connected to the MDC host.

Charging behaviour and SoC synchronisation 

The system ensures that the states of charge (SoC) of all connected batteries are synchronised as evenly as possible. In the event of differing storage capacities or individually specified minimum states of charge, the host automatically adjusts the charging and discharging power to suit the respective conditions. The aim of this control mechanism is to achieve as uniform a distribution of the state of charge as possible across all battery storage units. Due to the nature of the system, there is an SoC offset of approximately 5% between the host and the clients. As a result, the battery connected to the host always reaches both the maximum charge (100% SoC) and the set minimum SoC last. For battery charging, the host automatically utilises the energy from all PV inverters available on the domestic grid and coordinates its distribution across the entire storage system.

Communication and data logging

Special considerations during operation

During day-to-day operation, there are a number of system-specific characteristics to bear in mind:

In the event of a mains power failure whilst in backup mode, only the battery on the MDC host is used to supply power. In this case, the MDC clients, including their connected battery storage units, are deactivated. Central settings for battery usage are configured directly on the MDC host’s web server and then apply to the entire MDC network. Only individual parameters, such as the minimum state of charge, are set on the client devices.

The fundamental difference between an MDC host and an MDC client lies in their function within the system: the MDC host is responsible for central control and coordination, whilst the MDC clients, as connected devices, follow the host’s instructions. Control and system monitoring: MDC host.

The host is the central control unit for the entire MDC network. It monitors and controls all connected MDC-enabled devices on the home network. Clients are detected, connected and managed via the integrated device manager. The complete power flow diagram for the system is available exclusively on the host.

MDC client

Clients are controlled entirely by the host. The web server or a client’s display merely shows the operating data for the respective device. Information on the entire system or the complete energy flow is not available there.

Connection of energy meters and control devices 

MDC Host

The energy meter (KEM or KSEM) is connected directly to the host via an RS485 interface. External control components, such as district heating control receivers or control boxes in accordance with Section 14a of the German Energy Act (EnWG), are connected exclusively to the host. The host processes the measurement and control signals and distributes the relevant information within the network.

MDC client

Clients have no direct connection to the energy meter or to external control devices. They receive all necessary measurement values and control parameters from the host via LAN communication.

Battery management and backup power operation

MDC Host

MDC client

System Configuration and Communication 

MDC Host

MDC client

The Modbus protocol is enabled by default to allow the host to access device data. The connection to the host must be made via a wired LAN; communication via Wi-Fi is not supported.

EEBus Communication

MDC Host

MDC client

The clients are integrated into the EEBus communication of the overall system and provide the necessary connections to the EEBus counterpart device in accordance with the system configuration.

Multi Device Control (MDC) significantly expands the possibilities for system control compared to the traditional control system via the KOSTAL Smart Energy Meter (KSEM). MDC offers numerous advantages, particularly in relation to battery storage systems, smart energy management and current regulatory requirements.

Support for multiple battery storage systems 

A key advantage of MDC is the ability to centrally manage multiple battery storage systems within a single system.

• With standard KSEM control, only one battery-powered device can be managed.
• With MDC, however, up to three inverters with connected battery storage systems can be operated as a single network.
• This requires the ‘Battery Control with MDC’ product extension to be activated on the MDC host.

Support for dynamic electricity tariffs

MDC was developed to meet the requirements of modern energy markets and supports functions for utilising dynamic electricity tariffs.

• This enables the storage system to respond flexibly to variable electricity prices.
• The KSEM-based control system does not offer this capability to the same extent.

Compliance with regulatory requirements

MDC supports compliance with legal and grid-related requirements, for example in accordance with Section 9 of the EEG and Section 14a of the EnWG.

• The MDC host receives signals from control units such as an FNN control box or a remote control receiver.
• The relevant settings are then automatically forwarded to all connected MDC clients.
  
• This ensures that the power limitation for the entire system is coordinated and implemented in accordance with standards.
  

Centralised system visualisation

MDC provides a centralised overview of the entire energy system.

• The complete power flow diagram is displayed directly on the web server and on the MDC host’s screen.
• Energy flows, storage statuses and power values for all connected devices can be viewed in one place.
  
• With a KSEM-based solution, inverters previously had to be managed and monitored individually.
  

Simplified commissioning and configuration

Setting up an MDC network is now significantly more straightforward.

• New inverters are automatically detected and integrated via the MDC host’s device manager.
• Manual configuration of individual devices in KSEM is largely no longer necessary.
  
• This reduces both the set-up effort and the likelihood of errors during commissioning.

Intelligent energy and battery management 

MDC enables a significantly more intelligent use of available energy sources.

• Surplus AC energy from all PV inverters in the domestic grid can be automatically used to charge the battery.
• The MDC host coordinates the charging and discharging processes for all connected storage units.
  
• In addition, the states of charge (SoC) of the individual batteries are automatically balanced to ensure that the storage system is utilised as evenly as possible.