Do you need to collect field data from remote sites into one centralized application, historian or ERP ?
Then the Talk2M DataMailbox will probably answer your needs.

The DataMailbox service of Talk2M is an online data buffer that allows the easy retrieval of your Ewon gateway's historical data

Application developers can easily retrieve historical data from multiple Ewon gateways using the DataMailbox and a simple API call.

The Ewon gateway pushes its historical data to the DataMailbox running on Talk2M servers. This historical data is temporarily stored and is then available through the DMWeb API.
This HTTPS based protocol allows third party applications to retrieve data from the DataMailbox in an easy way.

The following DMWeb API request can be used to retrieve new historical samples:

The DataMailbox acts as an online data buffer. A point can be stored for up to 10 days beginning when it was sent to the DataMailbox. 
There is also a limit to the number of points that can be stored each month. Capacity and pricing are linked to the type of Talk2M account you own.  More information is available on the Ewon website.

Detailed info about the SDK for the DMWeb API - embedding all usefull tools and documentation - can be found on the DMWeb programming page.

The DMWeb API requires a Talk2M Developer ID !