Initial situation

A system house for the construction of industrial solar systems required a flexible internet connection to the proprietary portal system for maintenance, service, remote monitoring and for the provision of customer data via the portal.

Conditions

The solar systems were each equipped with a different number of inverters from different manufacturers. The inverter is connected via an RS485 interface on the one hand with a proprietary and on the other hand with a Modbus protocol. The coupling to the proprietary protocol was carried out by Axotec in cooperation with the system house.

Due to legal regulations, the tariff status information had to be read in at the same time as the energy data. This is achieved with four correspondingly designed digital inputs.

Due to the local conditions, no LAN connection for internet connection was available. The internet connection is therefore exclusively via a 4G connection with fallback to 3G / 2G. The network availability and quality is naturally very different from installation to installation. A basic requirement for cloud connections of this kind is to ensure 24/7 operation for years without user intervention. Particular attention should be paid to the automatic restoration of the cellular connection in the event of a connection being broken due to critical network coverage.

It was in this application a special requirement that the offline times were to bring to the absolute minimum possible. A permanent check of the connection as well as the development of a specially optimized restoration of the connection were necessary for this.