ARM board evaluation

[zoneblue]

Hang on, architecture summary clalification time:

If we assume that  the BB is colocated in the "gear room" for maximum direct connections. Its ONLY link to other gear is ethernet. If you wanna hook one or more wifi bridges to the ethernet, fine, no problem. 

For links to RE devices direct connect IF they have ethernet.

What im calling the communications board is ethernet connected to the arm board, all it does is talk to as many sensor units as you have, either near or far, either wired or wireless.  Greg covers options for this well above. I wasnt meaning ethernet for the sensor links, various wireless serial, very low power consumption, ideal.

For RE gear bereft of ethernet, what then? Some sort of small modular serial/usb/bluetooth to ethernet adapter board?  Modbus direct rs485?

My comment about webcontroll being bus challenged is that 1 wire is it, not gona work for communications, right? Its forte is sensors, and only those in ethernet cable reach of BB.

In case none of this makes sense, heres a picture. Whats the alternative to ethernet for the main coms bus?

[Gregy]

Ross - thanks for the details - that's great news and puts to rest my concerns over the Ds18d20s ..
And of course 1wire suffers those distance/topology constraints natively regardless. 
of course now It just means I'm even more anxious for the newer model - as a combo of the
Current WC and the newer will fit very well in my "other" automation (home) project  (along with its "IO shield" fingers crossed)

Hey. Nice  pics and great units - I will have a look at your site to learn more of your commercial products

[Gregy]

ZB
i knew this moment was coming at us fast - hence my attempts to put some structure around the " sensing module" discussion
and draw out the myriad of "bus options" for us to confront

Your diagram helps capture the generic structure well ...

herewith my attempt at some definitions

"RE" = a device that forms part of renewable energy system
- that can provide external access to its status and data on its operation either directly of via an adaptor
(eg PV Charge controller, battery charger, inverter, generator)

"adapter"= device for protocol conversion and interfacing to open or proprietary RE device

"Local sensor board" = ethernet connected hw interface that provides GPIO/special interfaces for connection of various sensors
(note this could also be a remote sensor board ... by extending the ethernet to outside)
hmmm need to think about calling this "local"
should it be renamed "ethernet sensor board" ... and put a block in each of both local and remote (BBP will not know or even care if
its local or remote, nor how its connected)

IMHO
1) ethernet
as shown is one of the options - no question - it covers various readily available modules we have been discussing
examples (using my proposed  modified naming in diagram)
"ethernet Sensor board" =  Webcontrol
"comms board"= emonBASE (because it has wireless capability for remotes, and also potential to add other sensing nodes)

2) comms board ... more to come

[Gregy]

oh just realised
should the generic diagram constrain adapter be connected only via ethernet -  or direct also?

example
RE= midnite CC
(uses modbus over RTU TCP - so it fits your current diagram) - ok
but will there be cases where BBP might need to interface direct  via serial or similar adaptor?
perhaps for present best to limit it to only via an ethernet interface?
.. up to you

[zoneblue]

Well i dont know. How many devices (that we care about) do not have ethernet? Outback pre mate 3 is probably the main RE device that comes to mind. The possible downside is having to support usb/serial/usb-to-serial converters of various brands, direct to various unknown arm boards.  Hence my idea of an adapter board, that would reduce the variables. But this is all just thinking out loud, its not something i have enough ecperience to say teriibly cateogrically either way.

I think we ought to make a short list of "supported hardware" or lets say priority hardware at some point. Controllers, midnite, outback, schieder, morninstar. 2 and 3 require addons, the latter i think is serial only.


Sunny island, Conext, Outback, top three inverters. All three have their own ecosystem, and accessorys, that may duplicate or overlap BB functionality.  However the point of BBP is to integrate everything.

Then theres the sundry items, like serial enabled battery monitors etc.  Probably the path of least resistance is an unpowered usb hub off of the arm board, and usb-serial converter to rs232 only RE devices.

[Gregy]

yep
exactly why i threw it to you
... because it becomes a nightmare as to how many and how to support
I agree - limit it at present to the most popular ... and constrain to ethernet access
(so keep your diagram as drawn for the adapter )

.. any thoughts on my other comments on the diagram and definitions?

[Gregy]

just to link the two parallel discussions
have a look at the last couple of posts in my sensor thread
http://midniteforum.com/index.php?topic=1439.msg11950#msg11950
http://midniteforum.com/index.php?topic=1439.msg11951#msg11951

Im converging on a proposal for your consideration -  that at least one candidate for the "comms board"= emonBASE

It provides a ethernet "gateway" for
- emonTX (4 x AC power flow measurements)
- remote wireless nodes inc (so far):
emonTH (humidity and temperature)
low pwr sensor and Tx node (TBC) https://shop.wickeddevice.com/product/assembled-low-power-sensor-and-transmitter-node
Jeenodes?

[zoneblue]

Im still time constrained this week, should ease next week. In the weekend i want to combine your hardware research posts into a single wiki page, and hopefully in the process get to digest it.
Your comments on architure sound fair enough to me.

Something that occured to me is that the role of ethernet has more factors than ive listed so far:

- bear in mind im a coder, ethernet is what i know == bias.
- past 4/5 ports we max out all common wifi bridge hardware such as the venerable linksys setup like ross uses. Thats a pretty common setup. 4/5 port hubs ditto. As drawn you would need a 5 port wifi bridge plus a 5 port switch. Or an 8 port switch. These two devices will use more power than the rest of the hardware combined, maybe even twice as much. There are a couple of low power wifi routers on the market, but the adafruit wifi shield uses 1.5W active, so thats probably a baseline.
- with the exception of the client legs, none of the sensor stuff needs anywhere near 100Mb/s bandwidth, so the power use is wasted, as is isolation and other benefits, given that all that gear is running in the same facility and of the same earth bus.

So could a combination of ethernet and something else (i2c, or spi, modbus even) work? Limit ethernet for ethernet support RE gear, the arm board and the eth link to clients. Thats 3-5 ports. Incorperate into the coms  board one of the serial protocols listed above to communicate with the other baords

[Gregy]

ZB
ive been updating the module structure (post #1 in my sensing module thread)
so if you feel its useful - you can use it as a basis for the wiki to bring structure to
BBP both hw and sw modules for sensing ? (note it needs the commenting scraped away)

i will make an attempt and try to post it or Pm it to to you as a formatted text file - for you to
adapt as you see fit for wiki

[zoneblue]

Alas the weekend got absorbed rearranging our DC disconnect for the deltec and various (spring) garden projects.

But i did get round to tidying up our blackbox gear, from what was a untidy tangle of wires in  teh corner of my desk, to what is now a sort of slightly tidier bread board type setup.

Watt meter confirms that the ethernet switch is the biggest power user by far.

Cubie with 1 ethernet, 1.2W  (no ethernet plugged, 0.7W)
Switch with 3 ethernet 2.2W. (no ethernet plugged 0.6W)

Inclusive of the pair of dc converters(5V,9V), high 90s eff.  3W total so far, and two spare ethernet ports, webcontrol mounted at bottom for  testing, space for arduino/whatever coms link to outdoor sensor box bottom right.

Cubie had 80 days up on it when it was uncerimoniously unpowered to rewire it.