There is a new addition to the Solar Monitor module family – SM2-BE (Bus Extension) module. Its purpose is to extend main unit’s possibilities even more, or rather the whole system’s. It is not one purpose module as it might seem from its name, but there are several functions added into it. Here is their overview.
There is often need to connect various devices, which are further from the unit than it is the normal range of a standard connection, to the Solar Monitor unit in a bigger PV plant or in a more complicated terrain. These are e.g. RTU units (HDO), temperature sensors, exposure sensors or wind speed sensors, switching relays, door contacts, etc. These devices are usually connected directly to the Solar Monitor unit, or better to say to one of the extension modules, which is closely connected to the unit via HBUS bus hidden in a DIN strip.
In case there is such a device in a bigger distance from the Solar Monitor unit, SM2-BE module reliably lengthens HBUS bus and enables to place the extension module up to 1200m distance from the main monitoring unit. One SM2-BE module is attached to the main unit and another SM2-BE module is attached to a remote extension module. Both SM2-BE modules then behave like the extension module is connected directly to the main Solar Monitor unit.
Various devices can be connected to the Solar Monitor unit via RS-485 (2x), RS-232 (1x) and Ethernet (1x) communication interfaces. Some devices communicating via RS-232 have a connector for a serial communication at their outputs, as we more likely know from older computers where it was used to connect e.g. a mouse. In order to easily connect these devices to the Solar Monitor unit we have provided the SM2-BE module with the same connector. Then you can use an ordinary serial cable to connect the device with the Solar Monitor unit, as it is visible in the following picture, where you can see a connection with an Xcom-232i communication module for Studer Innotec inverters.
Some of the PV plant parts are relatively often struck by lightning. The damages are often quite big and the monitoring system is damaged in many cases as well. Therefore we have used our new SM2-BE module and put a lightning protection in it. Devices communicating via RS-485 do not connect to the Solar Monitor unit, but just to the SM2-BE module, which has an interface for connecting RS-485 line.
The module provides overvoltage protection not only for supply voltage distribution, but for combined, rough and fine, overvoltage protection for RS-485 data line. Data line is protected from cross as well as from longitudinal overvoltage.
The monitoring system is reliably protected because SM2-BE module can intercept lightning strike as far as 1kA power. After the discharge ends the module functionality restores and the monitoring system continues working. The used lightning arrester can withstand up to 150 discharges according to IEC61643-21 norm.
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