Its More Than a Big Grey Box – Hardware Basics

Last time we discussed the holistic collection of data, both the must-have information
and the data points that seem to be small and inconsequential. But as we saw, all
data is important, its what we do with it that’s makes the difference.
So, data must be collected and managed. From this point on, it’s not about the why of
data, or what data needs to be collected, but then how this process is undertaken
and completed. Here is where we start talking about those big grey boxes.
To start with, let me include a very basic drawing of a very normal DAS or SCADA
system to refer to as we begin our discussions,

Let’s start by providing a general overview of each of the items shown in the above
drawing.

• Main communications enclosure – This enclosure houses the “brains” behind
  the DAS or SCADA system…the data logger. Plus, a power supply, optional UPS,
  Ethernet switch, cellular modem, terminals, circuit breaker and fuses.
• Network Enclosures – The field installed enclosure that houses the Ethernet
  switch, power supply, optional UPS, Modbus/TCP adapter if needed, terminal,
  circuit breaker and fuses.
• Weather Station – A series of outdoor mounted sensors that measure
  irradiance, ambient temperature, back of module temperature, wind speed
  and direction and a host of other meteorological information.
• Fiber Splicing Enclosure – (Not shown on the drawing) – A dedicated enclosure that provides a splice tray and related items to fusion splice the optical fiber independently of its associated communications enclosure.

We plan on creating several articles devoted to the art of fiber routing, splicing and connections.

Specialty Items (Usually provided by others)

• Inverters – Central or string
• Singke axis trackers
• Metering
• Protection Relays
• Transformers
• Plus, others

This is not intended to be an exhaustive list, but it’s a place to start beginning to
understand how DAS and SCADA communicate with the many different types of
devices that comprise a solar PV site. We will dig more into the particulars of these
enclosures and systems in future articles.
One closing note…one of the most important aspects of building and delivering top-
quality communications enclosures, is to build them to an approved set of standards
and have them tested by a recognized listing agency such as UL, CSA or ETL. At REIG,
we have earned the right to place the well-recognized UL sticker on our listed
enclosures, which lets the installer, owner, and inspector that this enclosure has met
the stringent standards required for safety, operation, and reliability. Yes, it costs us
more than some of the other agencies would, but we believe strongly that we build
some of the best systems possible, and the UP approval makes that belief real.
Until next time…