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Increase eWon's memory storage - phongpham - 15-06-2016

Hi all,

I have a question regarding to the eWon Flexy's system storage. From the General Reference Guide, the maximum physical flash memory in the eWon is 128 MB and for recording data is 19MB. Our application is needing more recording data storage.
I was wondering if we can use the integrated SD as an additional storage?

Please let me know.
Thank you very much.

RE: Increase eWon's memory storage - simon - 16-06-2016

No, at the moment, it is not possible to use the SD card to extend the eWON memory.
The SD card is only used to configure the eWON : https://ewon.biz/support/content/aug-062-ewon-configured-sd-card

I am wondering why you need more than 1 000 000 records stored locally ?
Do you intend to push these data to a central server somehow ?

RE: Increase eWon's memory storage - phongpham - 16-06-2016

Hi Simon,

Our analytic system is collecting ~50 sensors at 1Hz and we need at least 3 days of historical data locally.
All the historical data are logged into the eSync server and MySQL on our cloud.
we're currently developing a web interface on eWon web server, and historical/ real time data trends are one of the most important features for us.
Can we write some php script to query the data from the cloud to the eWon's embedded web server for the web client's display?

RE: Increase eWon's memory storage - simon - 17-06-2016

Is "50 sensors at 1 Hz" mandatory ? You could maybe record the Tags on deadband (when the value changes) ?
Retrieving data from eSync is not possible as it is (there is no existing php script for that), neither a good idea to my point of view. It is better to create your Web Interface (Trends...) on the central side or use a third party software.

RE: Increase eWon's memory storage - Kevin - 17-06-2016

(16-06-2016, 09:39 PM)phongpham Wrote: Hi Simon,

Our analytic system is collecting ~50 sensors at 1Hz and we need at least 3 days of historical data locally.
All the historical data are logged into the eSync server and MySQL on our cloud.
we're currently developing a web interface on eWon web server, and historical/ real time data trends are one of the most important features for us.
Can we write some php script to query the data from the cloud to the eWon's embedded web server for the web client's display?

Hello phongpham,

This solution depends on your specific needs; but it may work so I'll toss it out there.
The general idea is to limit data to what will actually give you useful data points. For instance, if I have a graph like the following:
Code:
Time, Value
1s, 5
2s, 6
3s, 7
4s, 8
5s, 9
6s, 9
7s, 9
8s, 8
7s, 7
...

You could imagine this graph may repeat and I'll have regular peaks, troughs and generally uninteresting data inbetween.
The question I should ask myself is: What information do I ACTUALLY need to know.

So, in the case of sensors, there's several different rules you could use to limit the amount of data you are receiving.

1. Deadband
Simon already mentioned this.
In reference to my graph, I could set a dead band of 2 and cut the information in half. IE:
Code:
Time, Value
1s, 5
3s, 7
5s, 9
7s, 7
...


2. Min and Max
This greatly depends on the analysis of the information you are trying to achieve. 
For some, it might suffice to grab min and max values over time. IE:
Code:
Time, Min, Max:
1s, 5, 5
2s, 5, 6
3s, 5, 7
4s, 5, 8
6s, 5, 9
...



3. Grab Only Peaks
Again, depending on the general trend of information, this may or may not be useful.
If you can access the program that is monitoring the sensors, you could keep an array of the past 5-10 records and simply pick the peak/trough to get recorded.

Code:
Time, Value
1s, 5     <--- Picked as trough
6s, 9     <--- Picked as peak
7s, 7     <--- Picked as trough
...


Depending on the specific data you need, you could create your own set of rules to eliminate as much redundant data as possible and extract useful information.
The methods I mentioned are fast, easy to implement and very inexpensive. There are many, many other ways to analyze data and attempt to pick out valuable points.

RE: Increase eWon's memory storage - jhinsch - 28-06-2016

Hi,
it would be nice if you can make a calculator in the WEB interface/GUI.
So you easily can see how much storage you are using and how many hours / days there is storage for.
Br, Jacob

Historical how much storage & hours - Jean-Yves - 02-08-2016

Hi,
Here find an excel sheet to know how much storage you are using and how many hours 








RE: Increase eWon's memory storage - mibu - 24-03-2017

Hello,

according FW release notes, Version 12.0s0 supports "User partition space extension with the SD card (EXT3)".

I read this documentation, but there is no word about logging.
Since I have no Flexy around for a test, I wonder, if the maximum amount of records is still 1.000.000?

Due to occasional bad 3G coverage, it's for me as well important to store more than that (until eSync DataMailbox is available again).

Regards, Michael

RE: Increase eWon's memory storage - simon - 24-03-2017

Michael,

Yes, it is still 1.000.000 timestamp records max.
The Extended User Memory (SD card) is used for storing files/reports (CSV files, Camera images,... for example) and not for extending the historical memory.

So, you can export the historical data to the SD card in the form of files using scripting (https://techforum.ewon.biz/thread-216.html) but there is no way to "restore" these exported data to the internal historical data memory of Flexy so that these data can be exported to DataMailBox or eSync transparently.

Regards