Com'X510 Standalone Logging Time

[KuanKhoon]

Good Morning to all,

My inaugural post for 2016. Starting with a very simple question, what is the duration the Com'X 510 can log for given the following,

1) Number of devices logging

2) Number of parameters logged per device

3) Logging frequency (1 minute, 5 minute, etc.)

I understand from the previous webex training that the logging time can be very flexible and also very long dependent on the above. However to date we do not have a documented guaranteed deliverable to the customer with the exception of saying we have a 4GB SD card (and the customer comes back to say can they have more? 4GB? we are going to 32GB standard.).

This is unlike for the previous EGX300 where we know, for every device, it is allotted 171072 entries. The more parameters, and the higher the logging frequency, you scale down accordingly.

Does the Com'X 510 work the same way?

Best Regards,

Tan Kuan Khoon

Senior Product Specialist

Partner & Industry Business

[JamesJeanette · Accepted solution]

Hello KK,

There are varying factors to consider; however here is what we support:

The Com'X 510 can support 32 devices at 30 topics each at 5 minute intervals for 2 years of stored historical data. 

The calculation above can be adapted...adding more devices, and less topics plus longer intervals or some variation.

We do not make any differences on the size of the SD Card. 

Adding Robert Jennings (Clay) here in case you need further information.

James

[KuanKhoon]

Hi James,

Thanks for the insights. Was pretty tied up the previous 1.5 weeks hence omitted to reply you until now.

Thus, it would look like the Com'X 510 has a flexible "table assignment" that allows it to scale up or down the logging duration with respect to the number of topic logged, the number of devices logging and frequency of the individual logging.

If I were to do the following maths, (32 devices) x (30 topics) x (12 entries per hour) = 2 years

We derive a total of (32devices x 30topics/device x 12entries/hour x 24hour/day x 365day/year x 2years) = 201,830,400 entries (wow! 200 million entries ++)

Using the above base number, we should be able to freely determine the total logging time according to number of devices, topics, logging entries per hour, etc. Is this calculation reasonable?

Best Regards,

Kuan Khoon

[JamesJeanette]

Hello KK,

I have confirmed with the team.

"The math is correct.  We store 10 bytes per measurement sample; any memory used for managing the data is negligible.  So 201,830,400 measurements * 10 bytes is only  2GByte of our 4 Gbyte SD card capacity."

James

Robert Jennings

[KuanKhoon]

Hi James,

Good to know the maths is correct. Hence, we are using 2GB out of the 4GB memory on the SD card and the automatic wear leveling algorithm on the SD card controller will do the magic to ensure longevity of the card.

On the side note, typical SD card memory cells have a longevity of 10000 write cycles, and we are writing in such a leisurely pace, I would expect the SD card to pretty much last "forever".

Best Regards,

Kuan Khoon

[Erwin_Paal]

Hallo James,

I'm a little confused about the management of storage.

We are aware that Com'X 510 can manage max 64 physical devices (like EGX300). Is there no longer this limitation?

In the manual, I haven't found any limitation about maximal possible managed devices.

How are the 'virtual meters' considered? I meen devices defined in the custom library, based on I/O from physical devices.

How is the process for storage management in Com'X 510?

We thought it is similar to the EGX. Memory is divided into 64 parts.

Then each part is divided according to number of topics into 'n topics' parts.

Each topic part is managed dynamic according to the number of logging entries (depending of log interval):

I've found that when changing the logging parameters (whether topics number or interval), we have no data loss in ComX.

The primary question for me is about a description of storage management in Com'X.

Then maybe we can better understand, the impact of changes the logging parameters.

When is the risk that customers lose their data?

I can't confirm what Kuan Khoon TAN had write in this post: Com'X510 Loss Of Logging Data When Reconfiguring Logging Parameters

The problem with the publication is:

     - the first timestamp is always the last timestamp sent + 1 * Interval time.

     - in periodcal publication first timestamp is depending on the timezone set in Com'x (for UTC +1 it's 1:00, for UTC+4 it's 4:00)

       That is not what the customer expects, he wants to have his local time 00:00.

     - the last timestamp is depending of the selected publication frequency or the time when manual publication was selcted.

That means we have only one incremental export of data.

However if manual publication was chosen then missing data in the periodic publication.

It's very important for next FW to have the ability to export data for selected devices, periods, start time.

Best Regards

Erwin Paal

[DavidVicente]

Hi James,

Does the same limit apply to ComX210, or do we have to consider that it can go up to more data based on his thinner firmware?

Thanks